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gerrit-public.fairphone.software / toolchain / llvm-project / cdfe20b97f55f4f493ebd6f15932780ae0789fe4 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Daniel Dunbar46d611a2012-04-19 20:20:34 +0000[diff] [blame]10 <link rel="stylesheet" href="_static/llvm.css" type="text/css">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling34bc34e2012-08-17 18:33:14 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr_auto_hide">'<tt>linkonce_odr_auto_hide</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Dan Gohmane36188f2012-09-21 18:21:48 +0000[diff] [blame]106 <li><a href="#tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a></li>
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]107 <li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]108 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]111 </ol>
112 </li>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]113 <li><a href="#module_flags">Module Flags Metadata</a>
114 <ol>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]115 <li><a href="#objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a></li>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]118 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
119 <ol>
120 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]121 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
122 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]123 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
124 Global Variable</a></li>
125 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
126 Global Variable</a></li>
127 </ol>
128 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#instref">Instruction Reference</a>
130 <ol>
131 <li><a href="#terminators">Terminator Instructions</a>
132 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
134 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]135 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]136 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]137 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]138 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]139 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 </ol>
141 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 <li><a href="#binaryops">Binary Operations</a>
143 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]144 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]145 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]147 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]149 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]150 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
151 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
152 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]153 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
154 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
155 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]156 </ol>
157 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
159 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]160 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
161 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
162 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]163 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]164 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]165 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]166 </ol>
167 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]168 <li><a href="#vectorops">Vector Operations</a>
169 <ol>
170 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
171 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
172 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]173 </ol>
174 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]175 <li><a href="#aggregateops">Aggregate Operations</a>
176 <ol>
177 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
178 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
179 </ol>
180 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]181 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]182 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]183 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
184 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
185 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
186 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
187 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
188 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]189 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]192 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]193 <ol>
194 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
195 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
198 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]199 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
200 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
201 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
202 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]203 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
204 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]205 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]206 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]207 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]208 <li><a href="#otherops">Other Operations</a>
209 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]210 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
211 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]213 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]214 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]215 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]216 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]217 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]218 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]219 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]220 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]221 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]222 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]223 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
224 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]225 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
226 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
227 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]230 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
231 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
233 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
234 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]237 <li><a href="#int_codegen">Code Generator Intrinsics</a>
238 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
240 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
241 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
242 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
243 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
244 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]245 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]246 </ol>
247 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]248 <li><a href="#int_libc">Standard C Library Intrinsics</a>
249 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]250 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
254 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]255 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
257 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]258 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
259 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]260 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Peter Collingbourne2165cf62012-07-03 12:25:40 +0000[diff] [blame]261 <li><a href="#int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a></li>
Dan Gohman0b3d7822012-07-26 17:43:27 +0000[diff] [blame]262 <li><a href="#int_floor">'<tt>llvm.floor.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]263 </ol>
264 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]265 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]266 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]267 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]268 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
269 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
270 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]273 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
274 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]275 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
276 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
277 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
278 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
279 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]280 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]281 </ol>
282 </li>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]283 <li><a href="#spec_arithmetic">Specialised Arithmetic Intrinsics</a>
284 <ol>
285 <li><a href="#fmuladd">'<tt>llvm.fmuladd</tt> Intrinsic</a></li>
286 </ol>
287 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]288 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
289 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]290 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
291 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]292 </ol>
293 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]294 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]295 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]296 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]297 <ol>
298 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]299 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]300 </ol>
301 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]302 <li><a href="#int_memorymarkers">Memory Use Markers</a>
303 <ol>
Jakub Staszak5fd147f2011-12-04 20:44:25 +0000[diff] [blame]304 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
305 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
306 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
307 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]308 </ol>
309 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]310 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]311 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]312 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]313 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]314 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]315 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]316 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]317 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]318 <li><a href="#int_debugtrap">
319 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]320 <li><a href="#int_stackprotector">
321 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Nuno Lopes4d6c8322012-07-05 17:37:07 +0000[diff] [blame]322 <li><a href="#int_objectsize">
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]323 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Nuno Lopes4d6c8322012-07-05 17:37:07 +0000[diff] [blame]324 <li><a href="#int_expect">
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]325 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Nuno Lopes4d6c8322012-07-05 17:37:07 +0000[diff] [blame]326 <li><a href="#int_donothing">
327 '<tt>llvm.donothing</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]328 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]329 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]330 </ol>
331 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]332</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]333
334<div class="doc_author">
335 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
336 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]337</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]338
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]339<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]340<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]341<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]343<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]344
345<p>This document is a reference manual for the LLVM assembly language. LLVM is
346 a Static Single Assignment (SSA) based representation that provides type
347 safety, low-level operations, flexibility, and the capability of representing
348 'all' high-level languages cleanly. It is the common code representation
349 used throughout all phases of the LLVM compilation strategy.</p>
350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]351</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]353<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]354<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]355<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]356
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]357<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]358
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359<p>The LLVM code representation is designed to be used in three different forms:
360 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
361 for fast loading by a Just-In-Time compiler), and as a human readable
362 assembly language representation. This allows LLVM to provide a powerful
363 intermediate representation for efficient compiler transformations and
364 analysis, while providing a natural means to debug and visualize the
365 transformations. The three different forms of LLVM are all equivalent. This
366 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]368<p>The LLVM representation aims to be light-weight and low-level while being
369 expressive, typed, and extensible at the same time. It aims to be a
370 "universal IR" of sorts, by being at a low enough level that high-level ideas
371 may be cleanly mapped to it (similar to how microprocessors are "universal
372 IR's", allowing many source languages to be mapped to them). By providing
373 type information, LLVM can be used as the target of optimizations: for
374 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]375 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]376 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]378<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]379<h4>
380 <a name="wellformed">Well-Formedness</a>
381</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]382
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]383<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]384
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]385<p>It is important to note that this document describes 'well formed' LLVM
386 assembly language. There is a difference between what the parser accepts and
387 what is considered 'well formed'. For example, the following instruction is
388 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]389
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]390<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]391%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392</pre>
393
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]394<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
395 LLVM infrastructure provides a verification pass that may be used to verify
396 that an LLVM module is well formed. This pass is automatically run by the
397 parser after parsing input assembly and by the optimizer before it outputs
398 bitcode. The violations pointed out by the verifier pass indicate bugs in
399 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]400
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]401</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]402
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]403</div>
404
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]405<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]406
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]407<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]408<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]409<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]410
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]411<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]412
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]413<p>LLVM identifiers come in two basic types: global and local. Global
414 identifiers (functions, global variables) begin with the <tt>'@'</tt>
415 character. Local identifiers (register names, types) begin with
416 the <tt>'%'</tt> character. Additionally, there are three different formats
417 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]419<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]420 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]421 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
422 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
423 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
424 other characters in their names can be surrounded with quotes. Special
425 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
426 ASCII code for the character in hexadecimal. In this way, any character
427 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]429 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]430 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]431
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]432 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]433 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]434</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]435
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]436<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]437 don't need to worry about name clashes with reserved words, and the set of
438 reserved words may be expanded in the future without penalty. Additionally,
439 unnamed identifiers allow a compiler to quickly come up with a temporary
440 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]442<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]443 languages. There are keywords for different opcodes
444 ('<tt><a href="#i_add">add</a></tt>',
445 '<tt><a href="#i_bitcast">bitcast</a></tt>',
446 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
447 ('<tt><a href="#t_void">void</a></tt>',
448 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
449 reserved words cannot conflict with variable names, because none of them
450 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
452<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]453 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]455<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]457<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]458%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459</pre>
460
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]461<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]463<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]464%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465</pre>
466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]467<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]469<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]470%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
471%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]472%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473</pre>
474
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]475<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
476 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]478<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]479 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]480 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]481
482 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]483 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]484
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]485 <li>Unnamed temporaries are numbered sequentially</li>
486</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]487
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]488<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]489 demonstrating instructions, we will follow an instruction with a comment that
490 defines the type and name of value produced. Comments are shown in italic
491 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]492
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]493</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]494
495<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]496<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]498<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]500<h3>
501 <a name="modulestructure">Module Structure</a>
502</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]503
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]504<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]506<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
507 translation unit of the input programs. Each module consists of functions,
508 global variables, and symbol table entries. Modules may be combined together
509 with the LLVM linker, which merges function (and global variable)
510 definitions, resolves forward declarations, and merges symbol table
511 entries. Here is an example of the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]512
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]513<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]514<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]515<a href="#identifiers">@.str</a> = <a href="#linkage_private">private</a>&nbsp;<a href="#globalvars">unnamed_addr</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00"&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]516
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]517<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]518<a href="#functionstructure">declare</a> i32 @puts(i8* <a href="#nocapture">nocapture</a>) <a href="#fnattrs">nounwind</a>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]519
520<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]521define i32 @main() { <i>; i32()* </i>&nbsp;
522 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]523 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.str, i64 0, i64 0
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]524
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]525 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]526 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]527 <a href="#i_ret">ret</a> i32 0&nbsp;
528}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]529
530<i>; Named metadata</i>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]531!1 = metadata !{i32 42}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]532!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]533</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]534
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]535<p>This example is made up of a <a href="#globalvars">global variable</a> named
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]536 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]538 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]539 "<tt>foo</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]540
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]541<p>In general, a module is made up of a list of global values (where both
542 functions and global variables are global values). Global values are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]543 represented by a pointer to a memory location (in this case, a pointer to an
544 array of char, and a pointer to a function), and have one of the
545 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]546
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]547</div>
548
549<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]550<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]551 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]552</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]553
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]554<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]555
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]556<p>All Global Variables and Functions have one of the following types of
557 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]558
559<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]561 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
562 by objects in the current module. In particular, linking code into a
563 module with an private global value may cause the private to be renamed as
564 necessary to avoid collisions. Because the symbol is private to the
565 module, all references can be updated. This doesn't show up in any symbol
566 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]567
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]568 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]569 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
570 assembler and evaluated by the linker. Unlike normal strong symbols, they
571 are removed by the linker from the final linked image (executable or
572 dynamic library).</dd>
573
574 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
575 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
576 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
577 linker. The symbols are removed by the linker from the final linked image
578 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]579
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]580 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]581 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]582 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
583 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]584
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]586 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]587 into the object file corresponding to the LLVM module. They exist to
588 allow inlining and other optimizations to take place given knowledge of
589 the definition of the global, which is known to be somewhere outside the
590 module. Globals with <tt>available_externally</tt> linkage are allowed to
591 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
592 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]593
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]595 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]596 the same name when linkage occurs. This can be used to implement
597 some forms of inline functions, templates, or other code which must be
598 generated in each translation unit that uses it, but where the body may
599 be overridden with a more definitive definition later. Unreferenced
600 <tt>linkonce</tt> globals are allowed to be discarded. Note that
601 <tt>linkonce</tt> linkage does not actually allow the optimizer to
602 inline the body of this function into callers because it doesn't know if
603 this definition of the function is the definitive definition within the
604 program or whether it will be overridden by a stronger definition.
605 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
606 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]607
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]608 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]609 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
610 <tt>linkonce</tt> linkage, except that unreferenced globals with
611 <tt>weak</tt> linkage may not be discarded. This is used for globals that
612 are declared "weak" in C source code.</dd>
613
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]615 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
616 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
617 global scope.
618 Symbols with "<tt>common</tt>" linkage are merged in the same way as
619 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]620 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]621 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]622 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
623 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]624
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]625
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]626 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]627 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]628 pointer to array type. When two global variables with appending linkage
629 are linked together, the two global arrays are appended together. This is
630 the LLVM, typesafe, equivalent of having the system linker append together
631 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]632
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]633 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 <dd>The semantics of this linkage follow the ELF object file model: the symbol
635 is weak until linked, if not linked, the symbol becomes null instead of
636 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]637
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
639 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 <dd>Some languages allow differing globals to be merged, such as two functions
641 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]642 that only equivalent globals are ever merged (the "one definition rule"
643 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644 and <tt>weak_odr</tt> linkage types to indicate that the global will only
645 be merged with equivalent globals. These linkage types are otherwise the
646 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]647
Bill Wendling34bc34e2012-08-17 18:33:14 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_linkonce_odr_auto_hide">linkonce_odr_auto_hide</a></b></tt></dt>
649 <dd>Similar to "<tt>linkonce_odr</tt>", but nothing in the translation unit
650 takes the address of this definition. For instance, functions that had an
651 inline definition, but the compiler decided not to inline it.
652 <tt>linkonce_odr_auto_hide</tt> may have only <tt>default</tt> visibility.
653 The symbols are removed by the linker from the final linked image
654 (executable or dynamic library).</dd>
655
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]657 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 visible, meaning that it participates in linkage and can be used to
659 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]660</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]661
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]662<p>The next two types of linkage are targeted for Microsoft Windows platform
663 only. They are designed to support importing (exporting) symbols from (to)
664 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]665
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]666<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]667 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]668 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]669 or variable via a global pointer to a pointer that is set up by the DLL
670 exporting the symbol. On Microsoft Windows targets, the pointer name is
671 formed by combining <code>__imp_</code> and the function or variable
672 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]673
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]674 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]675 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]676 pointer to a pointer in a DLL, so that it can be referenced with the
677 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
678 name is formed by combining <code>__imp_</code> and the function or
679 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]680</dl>
681
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]682<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
683 another module defined a "<tt>.LC0</tt>" variable and was linked with this
684 one, one of the two would be renamed, preventing a collision. Since
685 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
686 declarations), they are accessible outside of the current module.</p>
687
688<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]689 other than <tt>external</tt>, <tt>dllimport</tt>
690 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]691
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]692<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]693 or <tt>weak_odr</tt> linkages.</p>
694
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]695</div>
696
697<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]698<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]700</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]701
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]702<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]703
704<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]705 and <a href="#i_invoke">invokes</a> can all have an optional calling
706 convention specified for the call. The calling convention of any pair of
707 dynamic caller/callee must match, or the behavior of the program is
708 undefined. The following calling conventions are supported by LLVM, and more
709 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 specified) matches the target C calling conventions. This calling
715 convention supports varargs function calls and tolerates some mismatch in
716 the declared prototype and implemented declaration of the function (as
717 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]718
719 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]720 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]721 (e.g. by passing things in registers). This calling convention allows the
722 target to use whatever tricks it wants to produce fast code for the
723 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]724 (Application Binary Interface).
725 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]726 when this or the GHC convention is used.</a> This calling convention
727 does not support varargs and requires the prototype of all callees to
728 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]729
730 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]731 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]732 as possible under the assumption that the call is not commonly executed.
733 As such, these calls often preserve all registers so that the call does
734 not break any live ranges in the caller side. This calling convention
735 does not support varargs and requires the prototype of all callees to
736 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]737
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]738 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
739 <dd>This calling convention has been implemented specifically for use by the
740 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
741 It passes everything in registers, going to extremes to achieve this by
742 disabling callee save registers. This calling convention should not be
743 used lightly but only for specific situations such as an alternative to
744 the <em>register pinning</em> performance technique often used when
745 implementing functional programming languages.At the moment only X86
746 supports this convention and it has the following limitations:
747 <ul>
748 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
749 floating point types are supported.</li>
750 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
751 6 floating point parameters.</li>
752 </ul>
753 This calling convention supports
754 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
755 requires both the caller and callee are using it.
756 </dd>
757
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]758 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]759 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]760 target-specific calling conventions to be used. Target specific calling
761 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]762</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]763
764<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 support Pascal conventions or any other well-known target-independent
766 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]767
768</div>
769
770<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]771<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]772 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]773</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]774
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]775<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]777<p>All Global Variables and Functions have one of the following visibility
778 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]779
780<dl>
781 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]782 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]783 that the declaration is visible to other modules and, in shared libraries,
784 means that the declared entity may be overridden. On Darwin, default
785 visibility means that the declaration is visible to other modules. Default
786 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]787
788 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]789 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]790 object if they are in the same shared object. Usually, hidden visibility
791 indicates that the symbol will not be placed into the dynamic symbol
792 table, so no other module (executable or shared library) can reference it
793 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]794
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]795 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]796 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]797 the dynamic symbol table, but that references within the defining module
798 will bind to the local symbol. That is, the symbol cannot be overridden by
799 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]800</dl>
801
802</div>
803
804<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]805<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]806 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]807</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]808
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]809<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810
811<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]812 it easier to read the IR and make the IR more condensed (particularly when
813 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]815<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]816%mytype = type { %mytype*, i32 }
817</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]818
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]819<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]820 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]821 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]822
823<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]824 and that you can therefore specify multiple names for the same type. This
825 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
826 uses structural typing, the name is not part of the type. When printing out
827 LLVM IR, the printer will pick <em>one name</em> to render all types of a
828 particular shape. This means that if you have code where two different
829 source types end up having the same LLVM type, that the dumper will sometimes
830 print the "wrong" or unexpected type. This is an important design point and
831 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]832
833</div>
834
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]835<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]836<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]837 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]838</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]839
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]840<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]841
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]842<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843 instead of run-time. Global variables may optionally be initialized, may
844 have an explicit section to be placed in, and may have an optional explicit
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]845 alignment specified.</p>
846
847<p>A variable may be defined as <tt>thread_local</tt>, which
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]848 means that it will not be shared by threads (each thread will have a
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]849 separated copy of the variable). Not all targets support thread-local
850 variables. Optionally, a TLS model may be specified:</p>
851
852<dl>
853 <dt><b><tt>localdynamic</tt></b>:</dt>
854 <dd>For variables that are only used within the current shared library.</dd>
855
856 <dt><b><tt>initialexec</tt></b>:</dt>
857 <dd>For variables in modules that will not be loaded dynamically.</dd>
858
859 <dt><b><tt>localexec</tt></b>:</dt>
860 <dd>For variables defined in the executable and only used within it.</dd>
861</dl>
862
863<p>The models correspond to the ELF TLS models; see
864 <a href="http://people.redhat.com/drepper/tls.pdf">ELF
865 Handling For Thread-Local Storage</a> for more information on under which
866 circumstances the different models may be used. The target may choose a
867 different TLS model if the specified model is not supported, or if a better
868 choice of model can be made.</p>
869
870<p>A variable may be defined as a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]871 "constant," which indicates that the contents of the variable
872 will <b>never</b> be modified (enabling better optimization, allowing the
873 global data to be placed in the read-only section of an executable, etc).
874 Note that variables that need runtime initialization cannot be marked
875 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]876
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]877<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
878 constant, even if the final definition of the global is not. This capability
879 can be used to enable slightly better optimization of the program, but
880 requires the language definition to guarantee that optimizations based on the
881 'constantness' are valid for the translation units that do not include the
882 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]883
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]884<p>As SSA values, global variables define pointer values that are in scope
885 (i.e. they dominate) all basic blocks in the program. Global variables
886 always define a pointer to their "content" type because they describe a
887 region of memory, and all memory objects in LLVM are accessed through
888 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]889
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]890<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
891 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]892 like this can be merged with other constants if they have the same
893 initializer. Note that a constant with significant address <em>can</em>
894 be merged with a <tt>unnamed_addr</tt> constant, the result being a
895 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]896
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897<p>A global variable may be declared to reside in a target-specific numbered
898 address space. For targets that support them, address spaces may affect how
899 optimizations are performed and/or what target instructions are used to
900 access the variable. The default address space is zero. The address space
901 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]902
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]903<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]905
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]906<p>An explicit alignment may be specified for a global, which must be a power
907 of 2. If not present, or if the alignment is set to zero, the alignment of
908 the global is set by the target to whatever it feels convenient. If an
909 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]910 alignment. Targets and optimizers are not allowed to over-align the global
911 if the global has an assigned section. In this case, the extra alignment
912 could be observable: for example, code could assume that the globals are
913 densely packed in their section and try to iterate over them as an array,
914 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]916<p>For example, the following defines a global in a numbered address space with
917 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]918
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]919<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]920@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]921</pre>
922
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]923<p>The following example defines a thread-local global with
924 the <tt>initialexec</tt> TLS model:</p>
925
926<pre class="doc_code">
927@G = thread_local(initialexec) global i32 0, align 4
928</pre>
929
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]930</div>
931
932
933<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]934<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]935 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]936</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]937
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]938<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]939
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]940<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941 optional <a href="#linkage">linkage type</a>, an optional
942 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]943 <a href="#callingconv">calling convention</a>,
944 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]945 <a href="#paramattrs">parameter attribute</a> for the return type, a function
946 name, a (possibly empty) argument list (each with optional
947 <a href="#paramattrs">parameter attributes</a>), optional
948 <a href="#fnattrs">function attributes</a>, an optional section, an optional
949 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
950 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]951
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
953 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]954 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]955 <a href="#callingconv">calling convention</a>,
956 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]957 <a href="#paramattrs">parameter attribute</a> for the return type, a function
958 name, a possibly empty list of arguments, an optional alignment, and an
959 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]960
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]961<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]962 (Control Flow Graph) for the function. Each basic block may optionally start
963 with a label (giving the basic block a symbol table entry), contains a list
964 of instructions, and ends with a <a href="#terminators">terminator</a>
965 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]966
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]967<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]968 executed on entrance to the function, and it is not allowed to have
969 predecessor basic blocks (i.e. there can not be any branches to the entry
970 block of a function). Because the block can have no predecessors, it also
971 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]972
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]973<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]974 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]975
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]976<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]977 the alignment is set to zero, the alignment of the function is set by the
978 target to whatever it feels convenient. If an explicit alignment is
979 specified, the function is forced to have at least that much alignment. All
980 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]981
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]982<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]983 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]984
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]985<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]986<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]987define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]988 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
989 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
990 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
991 [<a href="#gc">gc</a>] { ... }
992</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]993
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]994</div>
995
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]996<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]997<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]998 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]999</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1001<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1002
1003<p>Aliases act as "second name" for the aliasee value (which can be either
1004 function, global variable, another alias or bitcast of global value). Aliases
1005 may have an optional <a href="#linkage">linkage type</a>, and an
1006 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]1007
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1008<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1009<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]1010@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]1011</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]1012
1013</div>
1014
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1015<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1016<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1017 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1018</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1019
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1020<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1021
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]1022<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1023 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]1024 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1025
1026<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1027<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1028; Some unnamed metadata nodes, which are referenced by the named metadata.
1029!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1030!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1031!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]1032; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1033!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1034</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1035
1036</div>
1037
1038<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1039<h3>
1040 <a name="paramattrs">Parameter Attributes</a>
1041</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1042
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1043<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1044
1045<p>The return type and each parameter of a function type may have a set of
1046 <i>parameter attributes</i> associated with them. Parameter attributes are
1047 used to communicate additional information about the result or parameters of
1048 a function. Parameter attributes are considered to be part of the function,
1049 not of the function type, so functions with different parameter attributes
1050 can have the same function type.</p>
1051
1052<p>Parameter attributes are simple keywords that follow the type specified. If
1053 multiple parameter attributes are needed, they are space separated. For
1054 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1055
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1056<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1057declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1058declare i32 @atoi(i8 zeroext)
1059declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1060</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1061
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1062<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1063 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1064
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1065<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1066
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1067<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1068 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1070 should be zero-extended to the extent required by the target's ABI (which
1071 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1072 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1073
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1074 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1075 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1076 should be sign-extended to the extent required by the target's ABI (which
1077 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1078 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1079
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1080 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1081 <dd>This indicates that this parameter or return value should be treated in a
1082 special target-dependent fashion during while emitting code for a function
1083 call or return (usually, by putting it in a register as opposed to memory,
1084 though some targets use it to distinguish between two different kinds of
1085 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1086
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1087 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1088 <dd><p>This indicates that the pointer parameter should really be passed by
1089 value to the function. The attribute implies that a hidden copy of the
1090 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1091 is made between the caller and the callee, so the callee is unable to
Chris Lattner747482c2012-05-30 00:40:23 +0000[diff] [blame]1092 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093 pointer arguments. It is generally used to pass structs and arrays by
1094 value, but is also valid on pointers to scalars. The copy is considered
1095 to belong to the caller not the callee (for example,
1096 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1097 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1098 values.</p>
1099
1100 <p>The byval attribute also supports specifying an alignment with
1101 the align attribute. It indicates the alignment of the stack slot to
1102 form and the known alignment of the pointer specified to the call site. If
1103 the alignment is not specified, then the code generator makes a
1104 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1105
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1106 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This indicates that the pointer parameter specifies the address of a
1108 structure that is the return value of the function in the source program.
1109 This pointer must be guaranteed by the caller to be valid: loads and
Duncan Sands271ea6c2012-10-04 13:36:31 +0000[diff] [blame]1110 stores to the structure may be assumed by the callee to not to trap and
1111 to be properly aligned. This may only be applied to the first parameter.
1112 This is not a valid attribute for return values. </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1114 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1115 <dd>This indicates that pointer values
1116 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1117 value do not alias pointer values which are not <i>based</i> on it,
1118 ignoring certain "irrelevant" dependencies.
1119 For a call to the parent function, dependencies between memory
1120 references from before or after the call and from those during the call
1121 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1122 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1123 The caller shares the responsibility with the callee for ensuring that
1124 these requirements are met.
1125 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1126 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1127<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1128 Note that this definition of <tt>noalias</tt> is intentionally
1129 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1130 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1131<br>
1132 For function return values, C99's <tt>restrict</tt> is not meaningful,
1133 while LLVM's <tt>noalias</tt> is.
1134 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1135
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1136 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1137 <dd>This indicates that the callee does not make any copies of the pointer
1138 that outlive the callee itself. This is not a valid attribute for return
1139 values.</dd>
1140
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1141 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1142 <dd>This indicates that the pointer parameter can be excised using the
1143 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1144 attribute for return values.</dd>
1145</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1146
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1147</div>
1148
1149<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1150<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1151 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1152</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1153
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1154<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1155
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1156<p>Each function may specify a garbage collector name, which is simply a
1157 string:</p>
1158
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1159<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1160define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1162
1163<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1164 collector which will cause the compiler to alter its output in order to
1165 support the named garbage collection algorithm.</p>
1166
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1167</div>
1168
1169<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1170<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1171 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1172</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1173
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1174<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1175
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1176<p>Function attributes are set to communicate additional information about a
1177 function. Function attributes are considered to be part of the function, not
1178 of the function type, so functions with different parameter attributes can
1179 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1180
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181<p>Function attributes are simple keywords that follow the type specified. If
1182 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1183
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1184<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1185define void @f() noinline { ... }
1186define void @f() alwaysinline { ... }
1187define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1188define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1189</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1190
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1191<dl>
Kostya Serebryanya5054ad2012-01-20 17:56:17 +0000[diff] [blame]1192 <dt><tt><b>address_safety</b></tt></dt>
1193 <dd>This attribute indicates that the address safety analysis
1194 is enabled for this function. </dd>
1195
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1196 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1197 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1198 the backend should forcibly align the stack pointer. Specify the
1199 desired alignment, which must be a power of two, in parentheses.
1200
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1201 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1202 <dd>This attribute indicates that the inliner should attempt to inline this
1203 function into callers whenever possible, ignoring any active inlining size
1204 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1205
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1206 <dt><tt><b>nonlazybind</b></tt></dt>
1207 <dd>This attribute suppresses lazy symbol binding for the function. This
1208 may make calls to the function faster, at the cost of extra program
1209 startup time if the function is not called during program startup.</dd>
1210
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1211 <dt><tt><b>inlinehint</b></tt></dt>
1212 <dd>This attribute indicates that the source code contained a hint that inlining
1213 this function is desirable (such as the "inline" keyword in C/C++). It
1214 is just a hint; it imposes no requirements on the inliner.</dd>
1215
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1216 <dt><tt><b>naked</b></tt></dt>
1217 <dd>This attribute disables prologue / epilogue emission for the function.
1218 This can have very system-specific consequences.</dd>
1219
1220 <dt><tt><b>noimplicitfloat</b></tt></dt>
1221 <dd>This attributes disables implicit floating point instructions.</dd>
1222
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1223 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1224 <dd>This attribute indicates that the inliner should never inline this
1225 function in any situation. This attribute may not be used together with
1226 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1227
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1228 <dt><tt><b>noredzone</b></tt></dt>
1229 <dd>This attribute indicates that the code generator should not use a red
1230 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1231
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1232 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1233 <dd>This function attribute indicates that the function never returns
1234 normally. This produces undefined behavior at runtime if the function
1235 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1236
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1237 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1238 <dd>This function attribute indicates that the function never returns with an
1239 unwind or exceptional control flow. If the function does unwind, its
1240 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1241
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1242 <dt><tt><b>optsize</b></tt></dt>
1243 <dd>This attribute suggests that optimization passes and code generator passes
1244 make choices that keep the code size of this function low, and otherwise
1245 do optimizations specifically to reduce code size.</dd>
1246
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1247 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1248 <dd>This attribute indicates that the function computes its result (or decides
1249 to unwind an exception) based strictly on its arguments, without
1250 dereferencing any pointer arguments or otherwise accessing any mutable
1251 state (e.g. memory, control registers, etc) visible to caller functions.
1252 It does not write through any pointer arguments
1253 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1254 changes any state visible to callers. This means that it cannot unwind
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1255 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1256
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1257 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1258 <dd>This attribute indicates that the function does not write through any
1259 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1260 arguments) or otherwise modify any state (e.g. memory, control registers,
1261 etc) visible to caller functions. It may dereference pointer arguments
1262 and read state that may be set in the caller. A readonly function always
1263 returns the same value (or unwinds an exception identically) when called
1264 with the same set of arguments and global state. It cannot unwind an
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1265 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1266
Bill Wendlingb437ab82011-12-05 21:27:54 +0000[diff] [blame]1267 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1268 <dd>This attribute indicates that this function can return twice. The
1269 C <code>setjmp</code> is an example of such a function. The compiler
1270 disables some optimizations (like tail calls) in the caller of these
1271 functions.</dd>
1272
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1273 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 <dd>This attribute indicates that the function should emit a stack smashing
1275 protector. It is in the form of a "canary"&mdash;a random value placed on
1276 the stack before the local variables that's checked upon return from the
1277 function to see if it has been overwritten. A heuristic is used to
1278 determine if a function needs stack protectors or not.<br>
1279<br>
1280 If a function that has an <tt>ssp</tt> attribute is inlined into a
1281 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1282 function will have an <tt>ssp</tt> attribute.</dd>
1283
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1284 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1285 <dd>This attribute indicates that the function should <em>always</em> emit a
1286 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1287 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1288<br>
1289 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1290 function that doesn't have an <tt>sspreq</tt> attribute or which has
1291 an <tt>ssp</tt> attribute, then the resulting function will have
1292 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1293
1294 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1295 <dd>This attribute indicates that the ABI being targeted requires that
1296 an unwind table entry be produce for this function even if we can
1297 show that no exceptions passes by it. This is normally the case for
1298 the ELF x86-64 abi, but it can be disabled for some compilation
1299 units.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1300</dl>
1301
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1302</div>
1303
1304<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1305<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1306 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1307</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1308
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1309<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1310
1311<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1312 the GCC "file scope inline asm" blocks. These blocks are internally
1313 concatenated by LLVM and treated as a single unit, but may be separated in
1314 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1315
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1316<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1317module asm "inline asm code goes here"
1318module asm "more can go here"
1319</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1320
1321<p>The strings can contain any character by escaping non-printable characters.
1322 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1323 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1324
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1325<p>The inline asm code is simply printed to the machine code .s file when
1326 assembly code is generated.</p>
1327
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1328</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1329
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1331<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1332 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1333</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1335<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1336
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1337<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1338 data is to be laid out in memory. The syntax for the data layout is
1339 simply:</p>
1340
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1341<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1342target datalayout = "<i>layout specification</i>"
1343</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1344
1345<p>The <i>layout specification</i> consists of a list of specifications
1346 separated by the minus sign character ('-'). Each specification starts with
1347 a letter and may include other information after the letter to define some
1348 aspect of the data layout. The specifications accepted are as follows:</p>
1349
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1350<dl>
1351 <dt><tt>E</tt></dt>
1352 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1353 bits with the most significance have the lowest address location.</dd>
1354
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1355 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1356 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1357 the bits with the least significance have the lowest address
1358 location.</dd>
1359
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1360 <dt><tt>S<i>size</i></tt></dt>
1361 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1362 of stack variables is limited to the natural stack alignment to avoid
1363 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1364 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1365 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1366
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1367 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1368 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1369 <i>preferred</i> alignments. All sizes are in bits. Specifying
1370 the <i>pref</i> alignment is optional. If omitted, the
1371 preceding <tt>:</tt> should be omitted too.</dd>
1372
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1373 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1374 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1375 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1376
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1377 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1378 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1379 <i>size</i>.</dd>
1380
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1381 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1382 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1383 <i>size</i>. Only values of <i>size</i> that are supported by the target
1384 will work. 32 (float) and 64 (double) are supported on all targets;
1385 80 or 128 (different flavors of long double) are also supported on some
1386 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1387
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1388 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1389 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1390 <i>size</i>.</dd>
1391
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1392 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1393 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1394 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1395
1396 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1397 <dd>This specifies a set of native integer widths for the target CPU
1398 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1399 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1400 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1401 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1402</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1403
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1404<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1405 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1406 specifications in the <tt>datalayout</tt> keyword. The default specifications
1407 are given in this list:</p>
1408
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1409<ul>
1410 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1411 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1412 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1413 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1414 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1415 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1416 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1417 alignment of 64-bits</li>
1418 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1419 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1420 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1421 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1422 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1423 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1424</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1425
1426<p>When LLVM is determining the alignment for a given type, it uses the
1427 following rules:</p>
1428
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1429<ol>
1430 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1431 specification is used.</li>
1432
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1433 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1434 smallest integer type that is larger than the bitwidth of the sought type
1435 is used. If none of the specifications are larger than the bitwidth then
Sylvestre Ledru35521e22012-07-23 08:51:15 +0000[diff] [blame]1436 the largest integer type is used. For example, given the default
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1437 specifications above, the i7 type will use the alignment of i8 (next
1438 largest) while both i65 and i256 will use the alignment of i64 (largest
1439 specified).</li>
1440
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1441 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1442 largest vector type that is smaller than the sought vector type will be
1443 used as a fall back. This happens because &lt;128 x double&gt; can be
1444 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1445</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1446
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1447<p>The function of the data layout string may not be what you expect. Notably,
1448 this is not a specification from the frontend of what alignment the code
1449 generator should use.</p>
1450
1451<p>Instead, if specified, the target data layout is required to match what the
1452 ultimate <em>code generator</em> expects. This string is used by the
1453 mid-level optimizers to
1454 improve code, and this only works if it matches what the ultimate code
1455 generator uses. If you would like to generate IR that does not embed this
1456 target-specific detail into the IR, then you don't have to specify the
1457 string. This will disable some optimizations that require precise layout
1458 information, but this also prevents those optimizations from introducing
1459 target specificity into the IR.</p>
1460
1461
1462
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1463</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1464
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1465<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1466<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1467 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1468</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1469
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1470<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1471
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1472<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1473with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1474is undefined. Pointer values are associated with address ranges
1475according to the following rules:</p>
1476
1477<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1478 <li>A pointer value is associated with the addresses associated with
1479 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1480 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1481 range of the variable's storage.</li>
1482 <li>The result value of an allocation instruction is associated with
1483 the address range of the allocated storage.</li>
1484 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1485 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1486 <li>An integer constant other than zero or a pointer value returned
1487 from a function not defined within LLVM may be associated with address
1488 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1489 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1490 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1491</ul>
1492
1493<p>A pointer value is <i>based</i> on another pointer value according
1494 to the following rules:</p>
1495
1496<ul>
1497 <li>A pointer value formed from a
1498 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1499 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1500 <li>The result value of a
1501 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1502 of the <tt>bitcast</tt>.</li>
1503 <li>A pointer value formed by an
1504 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1505 pointer values that contribute (directly or indirectly) to the
1506 computation of the pointer's value.</li>
1507 <li>The "<i>based</i> on" relationship is transitive.</li>
1508</ul>
1509
1510<p>Note that this definition of <i>"based"</i> is intentionally
1511 similar to the definition of <i>"based"</i> in C99, though it is
1512 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1513
1514<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1515<tt><a href="#i_load">load</a></tt> merely indicates the size and
1516alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1517interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1518<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1519and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1520
1521<p>Consequently, type-based alias analysis, aka TBAA, aka
1522<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1523LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1524additional information which specialized optimization passes may use
1525to implement type-based alias analysis.</p>
1526
1527</div>
1528
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1529<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1530<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1531 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1532</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1533
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1534<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1535
1536<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1537href="#i_store"><tt>store</tt></a>s, and <a
1538href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1539The optimizers must not change the number of volatile operations or change their
1540order of execution relative to other volatile operations. The optimizers
1541<i>may</i> change the order of volatile operations relative to non-volatile
1542operations. This is not Java's "volatile" and has no cross-thread
1543synchronization behavior.</p>
1544
1545</div>
1546
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1547<!-- ======================================================================= -->
1548<h3>
1549 <a name="memmodel">Memory Model for Concurrent Operations</a>
1550</h3>
1551
1552<div>
1553
1554<p>The LLVM IR does not define any way to start parallel threads of execution
1555or to register signal handlers. Nonetheless, there are platform-specific
1556ways to create them, and we define LLVM IR's behavior in their presence. This
1557model is inspired by the C++0x memory model.</p>
1558
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1559<p>For a more informal introduction to this model, see the
1560<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1561
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1562<p>We define a <i>happens-before</i> partial order as the least partial order
1563that</p>
1564<ul>
1565 <li>Is a superset of single-thread program order, and</li>
1566 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1567 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1568 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1569 creation, thread joining, etc., and by atomic instructions.
1570 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1571 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1572</ul>
1573
1574<p>Note that program order does not introduce <i>happens-before</i> edges
1575between a thread and signals executing inside that thread.</p>
1576
1577<p>Every (defined) read operation (load instructions, memcpy, atomic
1578loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1579(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1580stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1581initialized globals are considered to have a write of the initializer which is
1582atomic and happens before any other read or write of the memory in question.
1583For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1584any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1585
1586<ul>
1587 <li>If <var>write<sub>1</sub></var> happens before
1588 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1589 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1590 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1591 <li>If <var>R<sub>byte</sub></var> happens before
1592 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1593 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1594</ul>
1595
1596<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1597<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1598 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1599 is supposed to give guarantees which can support
1600 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1601 addresses which do not behave like normal memory. It does not generally
1602 provide cross-thread synchronization.)
1603 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1604 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1605 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1606 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1607 <var>R<sub>byte</sub></var> returns the value written by that
1608 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1609 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1610 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1611 values written. See the <a href="#ordering">Atomic Memory Ordering
1612 Constraints</a> section for additional constraints on how the choice
1613 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1614 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1615</ul>
1616
1617<p><var>R</var> returns the value composed of the series of bytes it read.
1618This implies that some bytes within the value may be <tt>undef</tt>
1619<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1620defines the semantics of the operation; it doesn't mean that targets will
1621emit more than one instruction to read the series of bytes.</p>
1622
1623<p>Note that in cases where none of the atomic intrinsics are used, this model
1624places only one restriction on IR transformations on top of what is required
1625for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1626otherwise be stored is not allowed in general. (Specifically, in the case
1627where another thread might write to and read from an address, introducing a
1628store can change a load that may see exactly one write into a load that may
1629see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1630
1631<!-- FIXME: This model assumes all targets where concurrency is relevant have
1632a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1633none of the backends currently in the tree fall into this category; however,
1634there might be targets which care. If there are, we want a paragraph
1635like the following:
1636
1637Targets may specify that stores narrower than a certain width are not
1638available; on such a target, for the purposes of this model, treat any
1639non-atomic write with an alignment or width less than the minimum width
1640as if it writes to the relevant surrounding bytes.
1641-->
1642
1643</div>
1644
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1645<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1646<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1647 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1648</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1649
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1650<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1651
1652<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1653<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1654<a href="#i_fence"><code>fence</code></a>,
1655<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1656<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1657that determines which other atomic instructions on the same address they
1658<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1659but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1660check those specs (see spec references in the
Nick Lewycky75499f52012-01-23 08:47:21 +0000[diff] [blame]1661<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1662<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1663treat these orderings somewhat differently since they don't take an address.
1664See that instruction's documentation for details.</p>
1665
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1666<p>For a simpler introduction to the ordering constraints, see the
1667<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1668
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1669<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1670<dt><code>unordered</code></dt>
1671<dd>The set of values that can be read is governed by the happens-before
1672partial order. A value cannot be read unless some operation wrote it.
1673This is intended to provide a guarantee strong enough to model Java's
1674non-volatile shared variables. This ordering cannot be specified for
1675read-modify-write operations; it is not strong enough to make them atomic
1676in any interesting way.</dd>
1677<dt><code>monotonic</code></dt>
1678<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1679total order for modifications by <code>monotonic</code> operations on each
1680address. All modification orders must be compatible with the happens-before
1681order. There is no guarantee that the modification orders can be combined to
1682a global total order for the whole program (and this often will not be
1683possible). The read in an atomic read-modify-write operation
1684(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1685<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1686reads the value in the modification order immediately before the value it
1687writes. If one atomic read happens before another atomic read of the same
1688address, the later read must see the same value or a later value in the
1689address's modification order. This disallows reordering of
1690<code>monotonic</code> (or stronger) operations on the same address. If an
1691address is written <code>monotonic</code>ally by one thread, and other threads
1692<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1693eventually see the write. This corresponds to the C++0x/C1x
1694<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1695<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1696<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1697a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1698operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1699<dt><code>release</code></dt>
1700<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1701writes a value which is subsequently read by an <code>acquire</code> operation,
1702it <i>synchronizes-with</i> that operation. (This isn't a complete
1703description; see the C++0x definition of a release sequence.) This corresponds
1704to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1705<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1706<code>acquire</code> and <code>release</code> operation on its address.
1707This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1708<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1709<dd>In addition to the guarantees of <code>acq_rel</code>
1710(<code>acquire</code> for an operation which only reads, <code>release</code>
1711for an operation which only writes), there is a global total order on all
1712sequentially-consistent operations on all addresses, which is consistent with
1713the <i>happens-before</i> partial order and with the modification orders of
1714all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1715preceding write to the same address in this global order. This corresponds
1716to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1717</dl>
1718
1719<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1720it only <i>synchronizes with</i> or participates in modification and seq_cst
1721total orderings with other operations running in the same thread (for example,
1722in signal handlers).</p>
1723
1724</div>
1725
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1726</div>
1727
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1728<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1729<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1730<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1731
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1732<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1733
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1734<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1735 intermediate representation. Being typed enables a number of optimizations
1736 to be performed on the intermediate representation directly, without having
1737 to do extra analyses on the side before the transformation. A strong type
1738 system makes it easier to read the generated code and enables novel analyses
1739 and transformations that are not feasible to perform on normal three address
1740 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1741
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1742<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1743<h3>
1744 <a name="t_classifications">Type Classifications</a>
1745</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1746
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1747<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1748
1749<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1750
1751<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1752 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1753 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1754 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1755 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1756 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1757 </tr>
1758 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1759 <td><a href="#t_floating">floating point</a></td>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1760 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1761 </tr>
1762 <tr>
1763 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1764 <td><a href="#t_integer">integer</a>,
1765 <a href="#t_floating">floating point</a>,
1766 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1767 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1768 <a href="#t_struct">structure</a>,
1769 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1770 <a href="#t_label">label</a>,
1771 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1772 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1773 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1774 <tr>
1775 <td><a href="#t_primitive">primitive</a></td>
1776 <td><a href="#t_label">label</a>,
1777 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1778 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1779 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1780 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1781 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1782 </tr>
1783 <tr>
1784 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1785 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1786 <a href="#t_function">function</a>,
1787 <a href="#t_pointer">pointer</a>,
1788 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1789 <a href="#t_vector">vector</a>,
1790 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1791 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1792 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1793 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1794</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1795
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1796<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1797 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1798 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1799
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1800</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1801
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1802<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1803<h3>
1804 <a name="t_primitive">Primitive Types</a>
1805</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1806
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1808
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1809<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1810 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1811
1812<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1813<h4>
1814 <a name="t_integer">Integer Type</a>
1815</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1816
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1817<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1818
1819<h5>Overview:</h5>
1820<p>The integer type is a very simple type that simply specifies an arbitrary
1821 bit width for the integer type desired. Any bit width from 1 bit to
1822 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1823
1824<h5>Syntax:</h5>
1825<pre>
1826 iN
1827</pre>
1828
1829<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1830 value.</p>
1831
1832<h5>Examples:</h5>
1833<table class="layout">
1834 <tr class="layout">
1835 <td class="left"><tt>i1</tt></td>
1836 <td class="left">a single-bit integer.</td>
1837 </tr>
1838 <tr class="layout">
1839 <td class="left"><tt>i32</tt></td>
1840 <td class="left">a 32-bit integer.</td>
1841 </tr>
1842 <tr class="layout">
1843 <td class="left"><tt>i1942652</tt></td>
1844 <td class="left">a really big integer of over 1 million bits.</td>
1845 </tr>
1846</table>
1847
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1848</div>
1849
1850<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1851<h4>
1852 <a name="t_floating">Floating Point Types</a>
1853</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1854
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1855<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1856
1857<table>
1858 <tbody>
1859 <tr><th>Type</th><th>Description</th></tr>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1860 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1861 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1862 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1863 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1864 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1865 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1866 </tbody>
1867</table>
1868
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_x86mmx">X86mmx Type</a>
1874</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1875
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1877
1878<h5>Overview:</h5>
1879<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1880
1881<h5>Syntax:</h5>
1882<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1883 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1884</pre>
1885
1886</div>
1887
1888<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1889<h4>
1890 <a name="t_void">Void Type</a>
1891</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1892
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1893<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1894
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1895<h5>Overview:</h5>
1896<p>The void type does not represent any value and has no size.</p>
1897
1898<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1899<pre>
1900 void
1901</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1902
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1903</div>
1904
1905<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1906<h4>
1907 <a name="t_label">Label Type</a>
1908</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1909
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1910<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1911
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1912<h5>Overview:</h5>
1913<p>The label type represents code labels.</p>
1914
1915<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1916<pre>
1917 label
1918</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1919
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1920</div>
1921
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_metadata">Metadata Type</a>
1925</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1926
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1928
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1929<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1930<p>The metadata type represents embedded metadata. No derived types may be
1931 created from metadata except for <a href="#t_function">function</a>
1932 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1933
1934<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1935<pre>
1936 metadata
1937</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1938
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1939</div>
1940
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1941</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1942
1943<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1944<h3>
1945 <a name="t_derived">Derived Types</a>
1946</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1947
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1948<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1949
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1950<p>The real power in LLVM comes from the derived types in the system. This is
1951 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1952 useful types. Each of these types contain one or more element types which
1953 may be a primitive type, or another derived type. For example, it is
1954 possible to have a two dimensional array, using an array as the element type
1955 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1956
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1957<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1958<h4>
1959 <a name="t_aggregate">Aggregate Types</a>
1960</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1961
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1962<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1963
1964<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands9aaec152011-12-14 15:44:20 +0000[diff] [blame]1965 member types. <a href="#t_array">Arrays</a> and
1966 <a href="#t_struct">structs</a> are aggregate types.
1967 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1968
1969</div>
1970
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1971<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1972<h4>
1973 <a name="t_array">Array Type</a>
1974</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1975
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1976<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1979<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1980 sequentially in memory. The array type requires a size (number of elements)
1981 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1982
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1983<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1984<pre>
1985 [&lt;# elements&gt; x &lt;elementtype&gt;]
1986</pre>
1987
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1989 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1990
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1991<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1992<table class="layout">
1993 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1994 <td class="left"><tt>[40 x i32]</tt></td>
1995 <td class="left">Array of 40 32-bit integer values.</td>
1996 </tr>
1997 <tr class="layout">
1998 <td class="left"><tt>[41 x i32]</tt></td>
1999 <td class="left">Array of 41 32-bit integer values.</td>
2000 </tr>
2001 <tr class="layout">
2002 <td class="left"><tt>[4 x i8]</tt></td>
2003 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2004 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2005</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2006<p>Here are some examples of multidimensional arrays:</p>
2007<table class="layout">
2008 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2009 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
2010 <td class="left">3x4 array of 32-bit integer values.</td>
2011 </tr>
2012 <tr class="layout">
2013 <td class="left"><tt>[12 x [10 x float]]</tt></td>
2014 <td class="left">12x10 array of single precision floating point values.</td>
2015 </tr>
2016 <tr class="layout">
2017 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
2018 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2019 </tr>
2020</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2021
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]2022<p>There is no restriction on indexing beyond the end of the array implied by
2023 a static type (though there are restrictions on indexing beyond the bounds
2024 of an allocated object in some cases). This means that single-dimension
2025 'variable sized array' addressing can be implemented in LLVM with a zero
2026 length array type. An implementation of 'pascal style arrays' in LLVM could
2027 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2028
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2029</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2030
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2031<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2032<h4>
2033 <a name="t_function">Function Type</a>
2034</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2035
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2036<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2037
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2038<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2039<p>The function type can be thought of as a function signature. It consists of
2040 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]2041 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]2042
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2043<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2044<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2045 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2046</pre>
2047
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2048<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2049 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2050 which indicates that the function takes a variable number of arguments.
2051 Variable argument functions can access their arguments with
2052 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2053 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2054 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2055
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2056<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2057<table class="layout">
2058 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2059 <td class="left"><tt>i32 (i32)</tt></td>
2060 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2061 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2062 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2063 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2064 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2065 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2066 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2067 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2068 </td>
2069 </tr><tr class="layout">
2070 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2071 <td class="left">A vararg function that takes at least one
2072 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2073 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2074 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2075 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2076 </tr><tr class="layout">
2077 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2078 <td class="left">A function taking an <tt>i32</tt>, returning a
2079 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2080 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2081 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2082</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2083
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2084</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2085
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2086<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2087<h4>
2088 <a name="t_struct">Structure Type</a>
2089</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2090
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2091<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2092
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2093<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2094<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2095 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2097<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2098 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2099 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2100 Structures in registers are accessed using the
2101 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2102 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2103
2104<p>Structures may optionally be "packed" structures, which indicate that the
2105 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2106 the elements. In non-packed structs, padding between field types is inserted
2107 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2108 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2109
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2110<p>Structures can either be "literal" or "identified". A literal structure is
2111 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2112 types are always defined at the top level with a name. Literal types are
2113 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2114 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2115 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2116</p>
2117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2118<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2119<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2120 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2121 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2122</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2123
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2125<table class="layout">
2126 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2127 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2128 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2129 </tr>
2130 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2131 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2132 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2133 second element is a <a href="#t_pointer">pointer</a> to a
2134 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2135 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2136 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2137 <tr class="layout">
2138 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2139 <td class="left">A packed struct known to be 5 bytes in size.</td>
2140 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2141</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2142
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2143</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2144
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2145<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2146<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2147 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2148</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2149
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2150<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2151
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2152<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2153<p>Opaque structure types are used to represent named structure types that do
2154 not have a body specified. This corresponds (for example) to the C notion of
2155 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2156
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2157<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2158<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2159 %X = type opaque
2160 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2162
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2163<h5>Examples:</h5>
2164<table class="layout">
2165 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2166 <td class="left"><tt>opaque</tt></td>
2167 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2168 </tr>
2169</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2170
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2171</div>
2172
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2173
2174
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2175<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2176<h4>
2177 <a name="t_pointer">Pointer Type</a>
2178</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2179
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2180<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2181
2182<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2183<p>The pointer type is used to specify memory locations.
2184 Pointers are commonly used to reference objects in memory.</p>
2185
2186<p>Pointer types may have an optional address space attribute defining the
2187 numbered address space where the pointed-to object resides. The default
2188 address space is number zero. The semantics of non-zero address
2189 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2190
2191<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2192 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2193
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2194<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2195<pre>
2196 &lt;type&gt; *
2197</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2198
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2199<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2200<table class="layout">
2201 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2202 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2203 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2204 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2205 </tr>
2206 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2207 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2208 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2209 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2210 <tt>i32</tt>.</td>
2211 </tr>
2212 <tr class="layout">
2213 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2214 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2215 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2216 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2217</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2218
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2219</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2220
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2221<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2222<h4>
2223 <a name="t_vector">Vector Type</a>
2224</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2225
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2226<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2227
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2228<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2229<p>A vector type is a simple derived type that represents a vector of elements.
2230 Vector types are used when multiple primitive data are operated in parallel
2231 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2232 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2233 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2234
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2235<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2236<pre>
2237 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2238</pre>
2239
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2240<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2241 may be any integer or floating point type, or a pointer to these types.
2242 Vectors of size zero are not allowed. </p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2243
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2244<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2245<table class="layout">
2246 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2247 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2248 <td class="left">Vector of 4 32-bit integer values.</td>
2249 </tr>
2250 <tr class="layout">
2251 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2252 <td class="left">Vector of 8 32-bit floating-point values.</td>
2253 </tr>
2254 <tr class="layout">
2255 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2256 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2257 </tr>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2258 <tr class="layout">
2259 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2260 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2261 </tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2262</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2263
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2264</div>
2265
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2266</div>
2267
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2268</div>
2269
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2270<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2271<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2272<!-- *********************************************************************** -->
2273
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2274<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2275
2276<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2277 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2278
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2279<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2280<h3>
2281 <a name="simpleconstants">Simple Constants</a>
2282</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2283
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2284<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2285
2286<dl>
2287 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2288 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2289 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2290
2291 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2292 <dd>Standard integers (such as '4') are constants of
2293 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2294 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2295
2296 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2297 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2298 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2299 notation (see below). The assembler requires the exact decimal value of a
2300 floating-point constant. For example, the assembler accepts 1.25 but
2301 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2302 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2303
2304 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2305 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2306 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2307</dl>
2308
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2309<p>The one non-intuitive notation for constants is the hexadecimal form of
2310 floating point constants. For example, the form '<tt>double
2311 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2312 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2313 constants are required (and the only time that they are generated by the
2314 disassembler) is when a floating point constant must be emitted but it cannot
2315 be represented as a decimal floating point number in a reasonable number of
2316 digits. For example, NaN's, infinities, and other special values are
2317 represented in their IEEE hexadecimal format so that assembly and disassembly
2318 do not cause any bits to change in the constants.</p>
2319
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2320<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2321 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2322 representation for double); half and float values must, however, be exactly
2323 representable as IEE754 half and single precision, respectively.
2324 Hexadecimal format is always used
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2325 for long double, and there are three forms of long double. The 80-bit format
2326 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2327 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2328 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2329 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2330 currently supported target uses this format. Long doubles will only work if
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]2331 they match the long double format on your target. The IEEE 16-bit format
2332 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2333 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2334
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2335<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2336</div>
2337
2338<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2339<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2340<a name="aggregateconstants"></a> <!-- old anchor -->
2341<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2342</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2343
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2344<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2345
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2346<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2347 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2348
2349<dl>
2350 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2351 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2352 type definitions (a comma separated list of elements, surrounded by braces
2353 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2354 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2355 Structure constants must have <a href="#t_struct">structure type</a>, and
2356 the number and types of elements must match those specified by the
2357 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2358
2359 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2360 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2361 definitions (a comma separated list of elements, surrounded by square
2362 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2363 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2364 the number and types of elements must match those specified by the
2365 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2366
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2367 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2368 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2369 definitions (a comma separated list of elements, surrounded by
2370 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2371 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2372 have <a href="#t_vector">vector type</a>, and the number and types of
2373 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2374
2375 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2376 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2377 value to zero of <em>any</em> type, including scalar and
2378 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2379 This is often used to avoid having to print large zero initializers
2380 (e.g. for large arrays) and is always exactly equivalent to using explicit
2381 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2382
2383 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2384 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2385 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2386 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2387 be interpreted as part of the instruction stream, metadata is a place to
2388 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2389</dl>
2390
2391</div>
2392
2393<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2394<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2395 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2396</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2397
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2398<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2399
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2400<p>The addresses of <a href="#globalvars">global variables</a>
2401 and <a href="#functionstructure">functions</a> are always implicitly valid
2402 (link-time) constants. These constants are explicitly referenced when
2403 the <a href="#identifiers">identifier for the global</a> is used and always
2404 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2405 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2406
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2407<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2408@X = global i32 17
2409@Y = global i32 42
2410@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2411</pre>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2416<h3>
2417 <a name="undefvalues">Undefined Values</a>
2418</h3>
2419
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2420<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2421
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2422<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2423 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2424 Undefined values may be of any type (other than '<tt>label</tt>'
2425 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2426
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2427<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2428 program is well defined no matter what value is used. This gives the
2429 compiler more freedom to optimize. Here are some examples of (potentially
2430 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2431
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = add %X, undef
2435 %B = sub %X, undef
2436 %C = xor %X, undef
2437Safe:
2438 %A = undef
2439 %B = undef
2440 %C = undef
2441</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2442
2443<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2444 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2445
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2446<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2447 %A = or %X, undef
2448 %B = and %X, undef
2449Safe:
2450 %A = -1
2451 %B = 0
2452Unsafe:
2453 %A = undef
2454 %B = undef
2455</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2456
2457<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2458 For example, if <tt>%X</tt> has a zero bit, then the output of the
2459 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2460 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2461 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2462 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2463 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2464 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2465 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2466
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2467<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2468 %A = select undef, %X, %Y
2469 %B = select undef, 42, %Y
2470 %C = select %X, %Y, undef
2471Safe:
2472 %A = %X (or %Y)
2473 %B = 42 (or %Y)
2474 %C = %Y
2475Unsafe:
2476 %A = undef
2477 %B = undef
2478 %C = undef
2479</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2480
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2481<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2482 branch) conditions can go <em>either way</em>, but they have to come from one
2483 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2484 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2485 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2486 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2487 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2488 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2489
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2490<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2491 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2492
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2493 %B = undef
2494 %C = xor %B, %B
2495
2496 %D = undef
2497 %E = icmp lt %D, 4
2498 %F = icmp gte %D, 4
2499
2500Safe:
2501 %A = undef
2502 %B = undef
2503 %C = undef
2504 %D = undef
2505 %E = undef
2506 %F = undef
2507</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2508
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2509<p>This example points out that two '<tt>undef</tt>' operands are not
2510 necessarily the same. This can be surprising to people (and also matches C
2511 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2512 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2513 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2514 its value over its "live range". This is true because the variable doesn't
2515 actually <em>have a live range</em>. Instead, the value is logically read
2516 from arbitrary registers that happen to be around when needed, so the value
2517 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2518 need to have the same semantics or the core LLVM "replace all uses with"
2519 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2520
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2521<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2522 %A = fdiv undef, %X
2523 %B = fdiv %X, undef
2524Safe:
2525 %A = undef
2526b: unreachable
2527</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2528
2529<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2530 value</em> and <em>undefined behavior</em>. An undefined value (like
2531 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2532 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2533 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2534 defined on SNaN's. However, in the second example, we can make a more
2535 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2536 arbitrary value, we are allowed to assume that it could be zero. Since a
2537 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2538 the operation does not execute at all. This allows us to delete the divide and
2539 all code after it. Because the undefined operation "can't happen", the
2540 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2541
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2542<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2543a: store undef -> %X
2544b: store %X -> undef
2545Safe:
2546a: &lt;deleted&gt;
2547b: unreachable
2548</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2549
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2550<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2551 undefined value can be assumed to not have any effect; we can assume that the
2552 value is overwritten with bits that happen to match what was already there.
2553 However, a store <em>to</em> an undefined location could clobber arbitrary
2554 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2555
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2556</div>
2557
2558<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2559<h3>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2560 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2561</h3>
2562
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2563<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2564
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2565<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2566 they also represent the fact that an instruction or constant expression which
2567 cannot evoke side effects has nevertheless detected a condition which results
2568 in undefined behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2569
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2570<p>There is currently no way of representing a poison value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2571 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2572 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2573
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2574<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2575
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2576<ul>
2577<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2578 their operands.</li>
2579
2580<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2581 to their dynamic predecessor basic block.</li>
2582
2583<li>Function arguments depend on the corresponding actual argument values in
2584 the dynamic callers of their functions.</li>
2585
2586<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2587 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2588 control back to them.</li>
2589
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2590<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]2591 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_resume"><tt>resume</tt></a>,
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2592 or exception-throwing call instructions that dynamically transfer control
2593 back to them.</li>
2594
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2595<li>Non-volatile loads and stores depend on the most recent stores to all of the
2596 referenced memory addresses, following the order in the IR
2597 (including loads and stores implied by intrinsics such as
2598 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2599
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2600<!-- TODO: In the case of multiple threads, this only applies if the store
2601 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2602
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2603<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2604
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2605<li>An instruction with externally visible side effects depends on the most
2606 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2607 the order in the IR. (This includes
2608 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2609
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2610<li>An instruction <i>control-depends</i> on a
2611 <a href="#terminators">terminator instruction</a>
2612 if the terminator instruction has multiple successors and the instruction
2613 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2614 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2615
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2616<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2617 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2618 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2619 successor.</li>
2620
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2621<li>Dependence is transitive.</li>
2622
2623</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2624
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2625<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2626 with the additional affect that any instruction which has a <i>dependence</i>
2627 on a poison value has undefined behavior.</p>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2628
2629<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2630
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2631<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2632entry:
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2633 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2634 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2635 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2636 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2637
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2638 store i32 %poison, i32* @g ; Poison value stored to memory.
2639 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2640
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2641 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2642
2643 %narrowaddr = bitcast i32* @g to i16*
2644 %wideaddr = bitcast i32* @g to i64*
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2645 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2646 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2647
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2648 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2649 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2650
2651true:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2652 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2653 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2654 br label %end
2655
2656end:
2657 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2658 ; Both edges into this PHI are
2659 ; control-dependent on %cmp, so this
2660 ; always results in a poison value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2661
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2662 store volatile i32 0, i32* @g ; This would depend on the store in %true
2663 ; if %cmp is true, or the store in %entry
2664 ; otherwise, so this is undefined behavior.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2665
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2666 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2667 ; The same branch again, but this time the
2668 ; true block doesn't have side effects.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2669
2670second_true:
2671 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2672 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2673
2674second_end:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2675 store volatile i32 0, i32* @g ; This time, the instruction always depends
2676 ; on the store in %end. Also, it is
2677 ; control-equivalent to %end, so this is
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2678 ; well-defined (ignoring earlier undefined
2679 ; behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2680</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2681
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2682</div>
2683
2684<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2685<h3>
2686 <a name="blockaddress">Addresses of Basic Blocks</a>
2687</h3>
2688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2689<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2690
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2691<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2692
2693<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2694 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2695 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2696
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2697<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2698 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2699 comparisons against null. Pointer equality tests between labels addresses
2700 results in undefined behavior &mdash; though, again, comparison against null
2701 is ok, and no label is equal to the null pointer. This may be passed around
2702 as an opaque pointer sized value as long as the bits are not inspected. This
2703 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2704 long as the original value is reconstituted before the <tt>indirectbr</tt>
2705 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2706
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2707<p>Finally, some targets may provide defined semantics when using the value as
2708 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2709
2710</div>
2711
2712
2713<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2714<h3>
2715 <a name="constantexprs">Constant Expressions</a>
2716</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2718<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2719
2720<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2721 to be used as constants. Constant expressions may be of
2722 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2723 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2724 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2725
2726<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2727 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2728 <dd>Truncate a constant to another type. The bit size of CST must be larger
2729 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2730
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2731 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2732 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2733 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2734
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2736 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2737 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2738
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Truncate a floating point constant to another floating point type. The
2741 size of CST must be larger than the size of TYPE. Both types must be
2742 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2743
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2744 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2745 <dd>Floating point extend a constant to another type. The size of CST must be
2746 smaller or equal to the size of TYPE. Both types must be floating
2747 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2748
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2750 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2751 constant. TYPE must be a scalar or vector integer type. CST must be of
2752 scalar or vector floating point type. Both CST and TYPE must be scalars,
2753 or vectors of the same number of elements. If the value won't fit in the
2754 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2755
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2756 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2757 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2758 constant. TYPE must be a scalar or vector integer type. CST must be of
2759 scalar or vector floating point type. Both CST and TYPE must be scalars,
2760 or vectors of the same number of elements. If the value won't fit in the
2761 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2762
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2764 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2765 constant. TYPE must be a scalar or vector floating point type. CST must be
2766 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2767 vectors of the same number of elements. If the value won't fit in the
2768 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2769
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2771 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2772 constant. TYPE must be a scalar or vector floating point type. CST must be
2773 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2774 vectors of the same number of elements. If the value won't fit in the
2775 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2776
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2777 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2778 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2779 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2780 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2781 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2782
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2783 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Sylvestre Ledru4fb32b12012-07-25 22:01:31 +0000[diff] [blame]2784 <dd>Convert an integer constant to a pointer constant. TYPE must be a pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2785 type. CST must be of integer type. The CST value is zero extended,
2786 truncated, or unchanged to make it fit in a pointer size. This one is
2787 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2788
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2789 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2790 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2791 are the same as those for the <a href="#i_bitcast">bitcast
2792 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2793
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2794 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2795 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2796 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2797 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2798 instruction, the index list may have zero or more indexes, which are
2799 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2800
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2801 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2802 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2803
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2804 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2805 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2806
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2807 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2808 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2809
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2810 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2811 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2812 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2813
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2814 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2815 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2816 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2817
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2818 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2819 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2820 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2821
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2822 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2823 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2824 constants. The index list is interpreted in a similar manner as indices in
2825 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2826 index value must be specified.</dd>
2827
2828 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2829 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2830 constants. The index list is interpreted in a similar manner as indices in
2831 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2832 index value must be specified.</dd>
2833
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2834 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2835 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2836 be any of the <a href="#binaryops">binary</a>
2837 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2838 on operands are the same as those for the corresponding instruction
2839 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2840</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2841
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2842</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2843
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2844</div>
2845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2846<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2847<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2848<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2849<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2850<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2851<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2852<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2853</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2854
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2855<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2856
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2857<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2858 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2859 a special value. This value represents the inline assembler as a string
2860 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2861 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2862 expression has side effects, and a flag indicating whether the function
2863 containing the asm needs to align its stack conservatively. An example
2864 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2865
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2866<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2867i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2868</pre>
2869
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2870<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
Nuno Lopesacd85352012-07-17 23:51:33 +0000[diff] [blame]2871 a <a href="#i_call"><tt>call</tt></a> or an
2872 <a href="#i_invoke"><tt>invoke</tt></a> instruction.
2873 Thus, typically we have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2874
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2875<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2876%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2877</pre>
2878
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2879<p>Inline asms with side effects not visible in the constraint list must be
2880 marked as having side effects. This is done through the use of the
2881 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2882
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2883<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2884call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2885</pre>
2886
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2887<p>In some cases inline asms will contain code that will not work unless the
2888 stack is aligned in some way, such as calls or SSE instructions on x86,
2889 yet will not contain code that does that alignment within the asm.
2890 The compiler should make conservative assumptions about what the asm might
2891 contain and should generate its usual stack alignment code in the prologue
2892 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2893
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2894<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2895call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2896</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2897
Chad Rosierd8c76102012-09-05 19:00:49 +0000[diff] [blame]2898<p>Inline asms also support using non-standard assembly dialects. The assumed
2899 dialect is ATT. When the '<tt>inteldialect</tt>' keyword is present, the
2900 inline asm is using the Intel dialect. Currently, ATT and Intel are the
2901 only supported dialects. An example is:</p>
Chad Rosierf42fad62012-09-05 00:08:17 +0000[diff] [blame]2902
2903<pre class="doc_code">
Chad Rosierd8c76102012-09-05 19:00:49 +0000[diff] [blame]2904call void asm inteldialect "eieio", ""()
Chad Rosierf42fad62012-09-05 00:08:17 +0000[diff] [blame]2905</pre>
2906
2907<p>If multiple keywords appear the '<tt>sideeffect</tt>' keyword must come
2908 first, the '<tt>alignstack</tt>' keyword second and the
Chad Rosierd8c76102012-09-05 19:00:49 +0000[diff] [blame]2909 '<tt>inteldialect</tt>' keyword last.</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2910
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2911<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2912<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913 documented here. Constraints on what can be done (e.g. duplication, moving,
2914 etc need to be documented). This is probably best done by reference to
2915 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2916 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2917
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2918<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2919<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2920 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2921</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2922
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2923<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2924
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2925<p>The call instructions that wrap inline asm nodes may have a
2926 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2927 integers. If present, the code generator will use the integer as the
2928 location cookie value when report errors through the <tt>LLVMContext</tt>
2929 error reporting mechanisms. This allows a front-end to correlate backend
2930 errors that occur with inline asm back to the source code that produced it.
2931 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2932
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2933<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2934call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2935...
2936!42 = !{ i32 1234567 }
2937</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2938
2939<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2940 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2941 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2942
2943</div>
2944
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2945</div>
2946
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2947<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2948<h3>
2949 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2950</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2951
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2952<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2953
2954<p>LLVM IR allows metadata to be attached to instructions in the program that
2955 can convey extra information about the code to the optimizers and code
2956 generator. One example application of metadata is source-level debug
2957 information. There are two metadata primitives: strings and nodes. All
2958 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2959 preceding exclamation point ('<tt>!</tt>').</p>
2960
2961<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2962 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2963 "<tt>xx</tt>" is the two digit hex code. For example:
2964 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2965
2966<p>Metadata nodes are represented with notation similar to structure constants
2967 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2968 exclamation point). Metadata nodes can have any values as their operand. For
2969 example:</p>
2970
2971<div class="doc_code">
2972<pre>
2973!{ metadata !"test\00", i32 10}
2974</pre>
2975</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2976
2977<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2978 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2979 example:</p>
2980
2981<div class="doc_code">
2982<pre>
2983!foo = metadata !{!4, !3}
2984</pre>
2985</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2986
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2987<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2988 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2989
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2990<div class="doc_code">
2991<pre>
2992call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2993</pre>
2994</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2995
2996<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2997 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2998 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2999
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]3000<div class="doc_code">
3001<pre>
3002%indvar.next = add i64 %indvar, 1, !dbg !21
3003</pre>
3004</div>
3005
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]3006<p>More information about specific metadata nodes recognized by the optimizers
3007 and code generator is found below.</p>
3008
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]3009<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]3010<h4>
3011 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
3012</h4>
3013
3014<div>
3015
3016<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
3017 suitable for doing TBAA. Instead, metadata is added to the IR to describe
3018 a type system of a higher level language. This can be used to implement
3019 typical C/C++ TBAA, but it can also be used to implement custom alias
3020 analysis behavior for other languages.</p>
3021
3022<p>The current metadata format is very simple. TBAA metadata nodes have up to
3023 three fields, e.g.:</p>
3024
3025<div class="doc_code">
3026<pre>
3027!0 = metadata !{ metadata !"an example type tree" }
3028!1 = metadata !{ metadata !"int", metadata !0 }
3029!2 = metadata !{ metadata !"float", metadata !0 }
3030!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
3031</pre>
3032</div>
3033
3034<p>The first field is an identity field. It can be any value, usually
3035 a metadata string, which uniquely identifies the type. The most important
3036 name in the tree is the name of the root node. Two trees with
3037 different root node names are entirely disjoint, even if they
3038 have leaves with common names.</p>
3039
3040<p>The second field identifies the type's parent node in the tree, or
3041 is null or omitted for a root node. A type is considered to alias
3042 all of its descendants and all of its ancestors in the tree. Also,
3043 a type is considered to alias all types in other trees, so that
3044 bitcode produced from multiple front-ends is handled conservatively.</p>
3045
3046<p>If the third field is present, it's an integer which if equal to 1
3047 indicates that the type is "constant" (meaning
3048 <tt>pointsToConstantMemory</tt> should return true; see
3049 <a href="AliasAnalysis.html#OtherItfs">other useful
3050 <tt>AliasAnalysis</tt> methods</a>).</p>
3051
3052</div>
3053
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]3054<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3055<h4>
Dan Gohmane36188f2012-09-21 18:21:48 +0000[diff] [blame]3056 <a name="tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a>
3057</h4>
3058
3059<div>
3060
3061<p>The <a href="#int_memcpy"><tt>llvm.memcpy</tt></a> is often used to implement
3062aggregate assignment operations in C and similar languages, however it is
3063defined to copy a contiguous region of memory, which is more than strictly
3064necessary for aggregate types which contain holes due to padding. Also, it
3065doesn't contain any TBAA information about the fields of the aggregate.</p>
3066
3067<p><tt>!tbaa.struct</tt> metadata can describe which memory subregions in a memcpy
3068are padding and what the TBAA tags of the struct are.</p>
3069
3070<p>The current metadata format is very simple. <tt>!tbaa.struct</tt> metadata nodes
3071 are a list of operands which are in conceptual groups of three. For each
Dan Gohman3397bb22012-09-21 18:41:30 +0000[diff] [blame]3072 group of three, the first operand gives the byte offset of a field in bytes,
3073 the second gives its size in bytes, and the third gives its
Dan Gohmane36188f2012-09-21 18:21:48 +0000[diff] [blame]3074 tbaa tag. e.g.:</p>
3075
3076<div class="doc_code">
3077<pre>
3078!4 = metadata !{ i64 0, i64 4, metadata !1, i64 8, i64 4, metadata !2 }
3079</pre>
3080</div>
3081
Dan Gohman3397bb22012-09-21 18:41:30 +0000[diff] [blame]3082<p>This describes a struct with two fields. The first is at offset 0 bytes
3083 with size 4 bytes, and has tbaa tag !1. The second is at offset 8 bytes
3084 and has size 4 bytes and has tbaa tag !2.</p>
Dan Gohmane36188f2012-09-21 18:21:48 +0000[diff] [blame]3085
3086<p>Note that the fields need not be contiguous. In this example, there is a
3087 4 byte gap between the two fields. This gap represents padding which
3088 does not carry useful data and need not be preserved.</p>
3089
3090</div>
3091
3092<!-- _______________________________________________________________________ -->
3093<h4>
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3094 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3095</h4>
3096
3097<div>
3098
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3099<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3100 type. It can be used to express the maximum acceptable error in the result of
3101 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3102 more efficient but less accurate method of computing it. ULP is defined as
3103 follows:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3104
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]3105<blockquote>
3106
3107<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3108 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3109 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3110 distance between the two non-equal finite floating-point numbers nearest
3111 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3112
3113</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3114
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3115<p>The metadata node shall consist of a single positive floating point number
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3116 representing the maximum relative error, for example:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3117
3118<div class="doc_code">
3119<pre>
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3120!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3121</pre>
3122</div>
3123
NAKAMURA Takumic9d9b922012-03-27 11:25:16 +0000[diff] [blame]3124</div>
3125
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3126<!-- _______________________________________________________________________ -->
3127<h4>
3128 <a name="range">'<tt>range</tt>' Metadata</a>
3129</h4>
3130
3131<div>
3132<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3133 expresses the possible ranges the loaded value is in. The ranges are
3134 represented with a flattened list of integers. The loaded value is known to
3135 be in the union of the ranges defined by each consecutive pair. Each pair
3136 has the following properties:</p>
3137<ul>
3138 <li>The type must match the type loaded by the instruction.</li>
3139 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3140 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3141 <li>The range is allowed to wrap.</li>
3142 <li>The range should not represent the full or empty set. That is,
3143 <tt>a!=b</tt>. </li>
3144</ul>
Rafael Espindolae3c5f3e2012-05-31 16:04:26 +0000[diff] [blame]3145<p> In addition, the pairs must be in signed order of the lower bound and
3146 they must be non-contiguous.</p>
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3147
3148<p>Examples:</p>
3149<div class="doc_code">
3150<pre>
3151 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3152 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3153 %c = load i8* %z, align 1, !range !2 ; Can only be 0, 1, 3, 4 or 5
Rafael Espindola97d77872012-05-31 13:45:46 +0000[diff] [blame]3154 %d = load i8* %z, align 1, !range !3 ; Can only be -2, -1, 3, 4 or 5
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3155...
3156!0 = metadata !{ i8 0, i8 2 }
3157!1 = metadata !{ i8 255, i8 2 }
3158!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindola97d77872012-05-31 13:45:46 +0000[diff] [blame]3159!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3160</pre>
3161</div>
3162</div>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3163</div>
3164
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3165</div>
3166
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3167<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3168<h2>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3169 <a name="module_flags">Module Flags Metadata</a>
3170</h2>
3171<!-- *********************************************************************** -->
3172
3173<div>
3174
3175<p>Information about the module as a whole is difficult to convey to LLVM's
3176 subsystems. The LLVM IR isn't sufficient to transmit this
3177 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3178 facilitate this. These flags are in the form of key / value pairs &mdash;
3179 much like a dictionary &mdash; making it easy for any subsystem who cares
3180 about a flag to look it up.</p>
3181
3182<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3183 triplets. Each triplet has the following form:</p>
3184
3185<ul>
3186 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3187 when two (or more) modules are merged together, and it encounters two (or
3188 more) metadata with the same ID. The supported behaviors are described
3189 below.</li>
3190
3191 <li>The second element is a metadata string that is a unique ID for the
3192 metadata. How each ID is interpreted is documented below.</li>
3193
3194 <li>The third element is the value of the flag.</li>
3195</ul>
3196
3197<p>When two (or more) modules are merged together, the resulting
3198 <tt>llvm.module.flags</tt> metadata is the union of the
3199 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3200 with the <i>Override</i> behavior, which may override another flag's value
3201 (see below).</p>
3202
3203<p>The following behaviors are supported:</p>
3204
3205<table border="1" cellspacing="0" cellpadding="4">
3206 <tbody>
3207 <tr>
3208 <th>Value</th>
3209 <th>Behavior</th>
3210 </tr>
3211 <tr>
3212 <td>1</td>
3213 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3214 <dl>
3215 <dt><b>Error</b></dt>
3216 <dd>Emits an error if two values disagree. It is an error to have an ID
3217 with both an Error and a Warning behavior.</dd>
3218 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3219 </td>
3220 </tr>
3221 <tr>
3222 <td>2</td>
3223 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3224 <dl>
3225 <dt><b>Warning</b></dt>
3226 <dd>Emits a warning if two values disagree.</dd>
3227 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3228 </td>
3229 </tr>
3230 <tr>
3231 <td>3</td>
3232 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3233 <dl>
3234 <dt><b>Require</b></dt>
3235 <dd>Emits an error when the specified value is not present or doesn't
3236 have the specified value. It is an error for two (or more)
3237 <tt>llvm.module.flags</tt> with the same ID to have the Require
3238 behavior but different values. There may be multiple Require flags
3239 per ID.</dd>
3240 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3241 </td>
3242 </tr>
3243 <tr>
3244 <td>4</td>
3245 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3246 <dl>
3247 <dt><b>Override</b></dt>
3248 <dd>Uses the specified value if the two values disagree. It is an
3249 error for two (or more) <tt>llvm.module.flags</tt> with the same
3250 ID to have the Override behavior but different values.</dd>
3251 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3252 </td>
3253 </tr>
3254 </tbody>
3255</table>
3256
3257<p>An example of module flags:</p>
3258
3259<pre class="doc_code">
3260!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3261!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3262!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3263!3 = metadata !{ i32 3, metadata !"qux",
3264 metadata !{
3265 metadata !"foo", i32 1
3266 }
3267}
3268!llvm.module.flags = !{ !0, !1, !2, !3 }
3269</pre>
3270
3271<ul>
3272 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3273 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3274 error if their values are not equal.</p></li>
3275
3276 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3277 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3278 value '37' if their values are not equal.</p></li>
3279
3280 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3281 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3282 warning if their values are not equal.</p></li>
3283
3284 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3285
3286<pre class="doc_code">
3287metadata !{ metadata !"foo", i32 1 }
3288</pre>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3289
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3290 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3291 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3292 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3293 the same value or an error will be issued.</p></li>
3294</ul>
3295
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3296
3297<!-- ======================================================================= -->
3298<h3>
3299<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3300</h3>
3301
3302<div>
3303
3304<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3305 in a special section called "image info". The metadata consists of a version
3306 number and a bitmask specifying what types of garbage collection are
3307 supported (if any) by the file. If two or more modules are linked together
3308 their garbage collection metadata needs to be merged rather than appended
3309 together.</p>
3310
3311<p>The Objective-C garbage collection module flags metadata consists of the
3312 following key-value pairs:</p>
3313
3314<table border="1" cellspacing="0" cellpadding="4">
Bill Wendling4fa13cc2012-03-06 09:23:25 +0000[diff] [blame]3315 <col width="30%">
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3316 <tbody>
3317 <tr>
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3318 <th>Key</th>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3319 <th>Value</th>
3320 </tr>
3321 <tr>
3322 <td><tt>Objective-C&nbsp;Version</tt></td>
3323 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3324 version. Valid values are 1 and 2.</td>
3325 </tr>
3326 <tr>
3327 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3328 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3329 section. Currently always 0.</td>
3330 </tr>
3331 <tr>
3332 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3333 <td align="left"><b>[Required]</b> &mdash; The section to place the
3334 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3335 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3336 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3337 </tr>
3338 <tr>
3339 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3340 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3341 collection is supported or not. Valid values are 0, for no garbage
3342 collection, and 2, for garbage collection supported.</td>
3343 </tr>
3344 <tr>
3345 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3346 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3347 collection is supported. If present, its value must be 6. This flag
3348 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3349 value 2.</td>
3350 </tr>
3351 </tbody>
3352</table>
3353
3354<p>Some important flag interactions:</p>
3355
3356<ul>
3357 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3358 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3359 2, then the resulting module has the <tt>Objective-C Garbage
3360 Collection</tt> flag set to 0.</li>
3361
3362 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3363 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3364</ul>
3365
3366</div>
3367
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3368</div>
3369
3370<!-- *********************************************************************** -->
3371<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3372 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3373</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3374<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3375<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3376<p>LLVM has a number of "magic" global variables that contain data that affect
3377code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3378of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3379section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3380by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3381
3382<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3383<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3384<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3385</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3386
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3387<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3388
3389<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3390href="#linkage_appending">appending linkage</a>. This array contains a list of
3391pointers to global variables and functions which may optionally have a pointer
3392cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3393
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3394<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3395<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3396@X = global i8 4
3397@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3398
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3399@llvm.used = appending global [2 x i8*] [
3400 i8* @X,
3401 i8* bitcast (i32* @Y to i8*)
3402], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3403</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3404</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3405
3406<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3407 compiler, assembler, and linker are required to treat the symbol as if there
3408 is a reference to the global that it cannot see. For example, if a variable
3409 has internal linkage and no references other than that from
3410 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3411 represent references from inline asms and other things the compiler cannot
3412 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3413
3414<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3415 object file to prevent the assembler and linker from molesting the
3416 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3417
3418</div>
3419
3420<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3421<h3>
3422 <a name="intg_compiler_used">
3423 The '<tt>llvm.compiler.used</tt>' Global Variable
3424 </a>
3425</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3426
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3427<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3428
3429<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3430 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3431 touching the symbol. On targets that support it, this allows an intelligent
3432 linker to optimize references to the symbol without being impeded as it would
3433 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3434
3435<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3436 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3437
3438</div>
3439
3440<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3441<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3442<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3443</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3444
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3445<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3446
3447<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3448<pre>
3449%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3450@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3451</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3452</div>
3453
3454<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3455 functions and associated priorities. The functions referenced by this array
3456 will be called in ascending order of priority (i.e. lowest first) when the
3457 module is loaded. The order of functions with the same priority is not
3458 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3459
3460</div>
3461
3462<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3463<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3464<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3465</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3466
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3467<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3468
3469<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3470<pre>
3471%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3472@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3473</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3474</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3475
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3476<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3477 and associated priorities. The functions referenced by this array will be
3478 called in descending order of priority (i.e. highest first) when the module
3479 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3480
3481</div>
3482
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3483</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3484
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3485<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3486<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3487<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3488
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3489<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3490
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491<p>The LLVM instruction set consists of several different classifications of
3492 instructions: <a href="#terminators">terminator
3493 instructions</a>, <a href="#binaryops">binary instructions</a>,
3494 <a href="#bitwiseops">bitwise binary instructions</a>,
3495 <a href="#memoryops">memory instructions</a>, and
3496 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3498<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3499<h3>
3500 <a name="terminators">Terminator Instructions</a>
3501</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3502
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3503<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3504
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3505<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3506 in a program ends with a "Terminator" instruction, which indicates which
3507 block should be executed after the current block is finished. These
3508 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3509 control flow, not values (the one exception being the
3510 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3511
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3512<p>The terminator instructions are:
3513 '<a href="#i_ret"><tt>ret</tt></a>',
3514 '<a href="#i_br"><tt>br</tt></a>',
3515 '<a href="#i_switch"><tt>switch</tt></a>',
3516 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3517 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3518 '<a href="#i_resume"><tt>resume</tt></a>', and
3519 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3520
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3521<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3522<h4>
3523 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3524</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3526<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3528<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3529<pre>
3530 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3531 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3532</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3533
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3534<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3535<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3536 a value) from a function back to the caller.</p>
3537
3538<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3539 value and then causes control flow, and one that just causes control flow to
3540 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3541
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3542<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3543<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3544 return value. The type of the return value must be a
3545 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3546
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3547<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3548 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3549 value or a return value with a type that does not match its type, or if it
3550 has a void return type and contains a '<tt>ret</tt>' instruction with a
3551 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3552
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3554<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3555 the calling function's context. If the caller is a
3556 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3557 instruction after the call. If the caller was an
3558 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3559 the beginning of the "normal" destination block. If the instruction returns
3560 a value, that value shall set the call or invoke instruction's return
3561 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3563<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3564<pre>
3565 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3566 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3567 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3568</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3569
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3570</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3571<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3572<h4>
3573 <a name="i_br">'<tt>br</tt>' Instruction</a>
3574</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3575
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3576<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3578<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3579<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3580 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3581 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3582</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3584<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3586 different basic block in the current function. There are two forms of this
3587 instruction, corresponding to a conditional branch and an unconditional
3588 branch.</p>
3589
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3590<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3591<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3592 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3593 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3594 target.</p>
3595
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3597<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3598 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3599 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3600 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3601
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3602<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3603<pre>
3604Test:
3605 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3606 br i1 %cond, label %IfEqual, label %IfUnequal
3607IfEqual:
3608 <a href="#i_ret">ret</a> i32 1
3609IfUnequal:
3610 <a href="#i_ret">ret</a> i32 0
3611</pre>
3612
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3613</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3614
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3615<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3616<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3617 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3618</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3619
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3620<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3621
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3622<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3623<pre>
3624 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3625</pre>
3626
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3627<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3628<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629 several different places. It is a generalization of the '<tt>br</tt>'
3630 instruction, allowing a branch to occur to one of many possible
3631 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3632
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3634<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3636 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3637 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3638
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3639<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3640<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3641 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3642 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3643 transferred to the corresponding destination; otherwise, control flow is
3644 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3645
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3646<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3647<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3648 <tt>switch</tt> instruction, this instruction may be code generated in
3649 different ways. For example, it could be generated as a series of chained
3650 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3651
3652<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3653<pre>
3654 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3655 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3656 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3657
3658 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3659 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3660
3661 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3662 switch i32 %val, label %otherwise [ i32 0, label %onzero
3663 i32 1, label %onone
3664 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3665</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3666
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3667</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3668
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3669
3670<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3671<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3672 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3673</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3674
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3675<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3676
3677<h5>Syntax:</h5>
3678<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3679 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3680</pre>
3681
3682<h5>Overview:</h5>
3683
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3684<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3685 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3686 "<tt>address</tt>". Address must be derived from a <a
3687 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3688
3689<h5>Arguments:</h5>
3690
3691<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3692 rest of the arguments indicate the full set of possible destinations that the
3693 address may point to. Blocks are allowed to occur multiple times in the
3694 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3695
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3696<p>This destination list is required so that dataflow analysis has an accurate
3697 understanding of the CFG.</p>
3698
3699<h5>Semantics:</h5>
3700
3701<p>Control transfers to the block specified in the address argument. All
3702 possible destination blocks must be listed in the label list, otherwise this
3703 instruction has undefined behavior. This implies that jumps to labels
3704 defined in other functions have undefined behavior as well.</p>
3705
3706<h5>Implementation:</h5>
3707
3708<p>This is typically implemented with a jump through a register.</p>
3709
3710<h5>Example:</h5>
3711<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3712 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3713</pre>
3714
3715</div>
3716
3717
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3719<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3720 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3721</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3722
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3723<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3725<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3726<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3727 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3728 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3729</pre>
3730
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3731<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3732<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3733 function, with the possibility of control flow transfer to either the
3734 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3735 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3736 control flow will return to the "normal" label. If the callee (or any
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3737 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3738 instruction or other exception handling mechanism, control is interrupted and
3739 continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3740
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3741<p>The '<tt>exception</tt>' label is a
3742 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3743 exception. As such, '<tt>exception</tt>' label is required to have the
3744 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosierc28f3e92011-12-09 02:00:44 +0000[diff] [blame]3745 the information about the behavior of the program after unwinding
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3746 happens, as its first non-PHI instruction. The restrictions on the
3747 "<tt>landingpad</tt>" instruction's tightly couples it to the
3748 "<tt>invoke</tt>" instruction, so that the important information contained
3749 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3750 code motion.</p>
3751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3752<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3753<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3755<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3756 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3757 convention</a> the call should use. If none is specified, the call
3758 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3759
3760 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3761 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3762 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3763
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3764 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3765 function value being invoked. In most cases, this is a direct function
3766 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3767 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3768
3769 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3770 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3771
3772 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3773 signature argument types and parameter attributes. All arguments must be
3774 of <a href="#t_firstclass">first class</a> type. If the function
3775 signature indicates the function accepts a variable number of arguments,
3776 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3777
3778 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3779 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3780
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3781 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3782 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3783 handling mechanism.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3784
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3785 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3787 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3788</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3789
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3790<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3791<p>This instruction is designed to operate as a standard
3792 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3793 primary difference is that it establishes an association with a label, which
3794 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3795
3796<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3798 exception. Additionally, this is important for implementation of
3799 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3801<p>For the purposes of the SSA form, the definition of the value returned by the
3802 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3803 block to the "normal" label. If the callee unwinds then no return value is
3804 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3806<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3807<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3808 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3809 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3810 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3811 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3812</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3813
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3814</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3815
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3816 <!-- _______________________________________________________________________ -->
3817
3818<h4>
3819 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3820</h4>
3821
3822<div>
3823
3824<h5>Syntax:</h5>
3825<pre>
3826 resume &lt;type&gt; &lt;value&gt;
3827</pre>
3828
3829<h5>Overview:</h5>
3830<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3831 successors.</p>
3832
3833<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3834<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3835 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3836 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3837
3838<h5>Semantics:</h5>
3839<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3840 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3841 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3842
3843<h5>Example:</h5>
3844<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3845 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3846</pre>
3847
3848</div>
3849
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3850<!-- _______________________________________________________________________ -->
3851
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3852<h4>
3853 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3854</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3855
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3856<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3857
3858<h5>Syntax:</h5>
3859<pre>
3860 unreachable
3861</pre>
3862
3863<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3864<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3865 instruction is used to inform the optimizer that a particular portion of the
3866 code is not reachable. This can be used to indicate that the code after a
3867 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3868
3869<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3870<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3871
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3872</div>
3873
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3874</div>
3875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3876<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3877<h3>
3878 <a name="binaryops">Binary Operations</a>
3879</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3880
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3881<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3882
3883<p>Binary operators are used to do most of the computation in a program. They
3884 require two operands of the same type, execute an operation on them, and
3885 produce a single value. The operands might represent multiple data, as is
3886 the case with the <a href="#t_vector">vector</a> data type. The result value
3887 has the same type as its operands.</p>
3888
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3889<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3890
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3892<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3893 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3894</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3895
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3896<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3897
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3899<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3900 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3901 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3902 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3903 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3904</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3905
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3907<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3910<p>The two arguments to the '<tt>add</tt>' instruction must
3911 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3912 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3915<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3916
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3917<p>If the sum has unsigned overflow, the result returned is the mathematical
3918 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3919
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920<p>Because LLVM integers use a two's complement representation, this instruction
3921 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3922
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3923<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3924 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3925 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3926 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3927 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3930<pre>
3931 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3932</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3933
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3934</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3935
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3936<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3937<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3938 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3939</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3940
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3941<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3942
3943<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3944<pre>
3945 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3946</pre>
3947
3948<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3949<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3950
3951<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3952<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3953 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3954 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3955
3956<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3957<p>The value produced is the floating point sum of the two operands.</p>
3958
3959<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3960<pre>
3961 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3963
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3964</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3966<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3967<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3968 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3969</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3970
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3971<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3974<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3975 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3976 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3977 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3978 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3979</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3980
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3981<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3982<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3983 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3984
3985<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3986 '<tt>neg</tt>' instruction present in most other intermediate
3987 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3989<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3990<p>The two arguments to the '<tt>sub</tt>' instruction must
3991 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3992 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3993
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3994<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3995<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3996
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3997<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3999 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4000
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4001<p>Because LLVM integers use a two's complement representation, this instruction
4002 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4003
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4004<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4005 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4006 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4007 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]4008 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4009
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4010<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]4011<pre>
4012 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4013 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4014</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4015
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4016</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4017
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4018<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4019<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4020 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4021</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4022
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4023<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4024
4025<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4026<pre>
4027 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4028</pre>
4029
4030<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4031<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4032 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4033
4034<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4035 '<tt>fneg</tt>' instruction present in most other intermediate
4036 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4037
4038<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]4039<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4041 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4042
4043<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4044<p>The value produced is the floating point difference of the two operands.</p>
4045
4046<h5>Example:</h5>
4047<pre>
4048 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
4049 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
4050</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4052</div>
4053
4054<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4055<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4056 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4057</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4058
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4059<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4060
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4061<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4062<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4063 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]4064 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4065 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4066 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4067</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4069<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4070<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4072<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4073<p>The two arguments to the '<tt>mul</tt>' instruction must
4074 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4075 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4076
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4077<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4078<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4079
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4080<p>If the result of the multiplication has unsigned overflow, the result
4081 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
4082 width of the result.</p>
4083
4084<p>Because LLVM integers use a two's complement representation, and the result
4085 is the same width as the operands, this instruction returns the correct
4086 result for both signed and unsigned integers. If a full product
4087 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4088 be sign-extended or zero-extended as appropriate to the width of the full
4089 product.</p>
4090
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4091<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4092 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4093 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4094 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]4095 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4096
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4097<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4098<pre>
4099 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4100</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4101
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4102</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4103
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4104<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4105<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4106 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4107</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4108
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4109<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4110
4111<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4112<pre>
4113 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4114</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4115
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4116<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4118
4119<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4120<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4121 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4122 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4123
4124<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4125<p>The value produced is the floating point product of the two operands.</p>
4126
4127<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4128<pre>
4129 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4130</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4132</div>
4133
4134<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4135<h4>
4136 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4137</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4138
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4139<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4140
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4141<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4142<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4143 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4144 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4145</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4146
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4147<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4148<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4149
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4150<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4151<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4152 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4153 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4154
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4155<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4156<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4157
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4158<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4159 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4160
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4161<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4163<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4164 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4165 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4166
4167
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4168<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4169<pre>
4170 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4171</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4172
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4173</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4174
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4175<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4176<h4>
4177 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4178</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4179
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4180<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4181
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4182<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4183<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4184 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]4185 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4186</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4187
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4188<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4189<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4190
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4191<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4192<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4193 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4194 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4195
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4196<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4197<p>The value produced is the signed integer quotient of the two operands rounded
4198 towards zero.</p>
4199
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4200<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4201 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4202
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4203<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4204 undefined behavior; this is a rare case, but can occur, for example, by doing
4205 a 32-bit division of -2147483648 by -1.</p>
4206
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]4207<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4208 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]4209 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4210
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4211<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212<pre>
4213 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4214</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4215
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4216</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4217
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4218<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4219<h4>
4220 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4221</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4223<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4224
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4225<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4226<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4227 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4228</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4229
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4230<h5>Overview:</h5>
4231<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4232
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4233<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4234<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4235 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4236 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4237
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4238<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4239<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4241<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4242<pre>
4243 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4244</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4245
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4246</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4247
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4248<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4249<h4>
4250 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4251</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4252
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4253<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4254
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4255<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4256<pre>
4257 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4258</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4259
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4260<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4261<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4262 division of its two arguments.</p>
4263
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4264<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4265<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4266 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4267 values. Both arguments must have identical types.</p>
4268
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4269<h5>Semantics:</h5>
4270<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4271 This instruction always performs an unsigned division to get the
4272 remainder.</p>
4273
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4274<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4275 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4276
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4277<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4279<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280<pre>
4281 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4282</pre>
4283
4284</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4287<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4288 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4289</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4290
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4291<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4292
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4293<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4294<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4295 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4296</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4297
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4298<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4300 division of its two operands. This instruction can also take
4301 <a href="#t_vector">vector</a> versions of the values in which case the
4302 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]4303
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4304<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4305<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4306 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4307 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4308
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4309<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4310<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4311 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4312 <i>modulo</i> operator (where the result is either zero or has the same sign
4313 as the divisor, <tt>op2</tt>) of a value.
4314 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4315 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4316 Math Forum</a>. For a table of how this is implemented in various languages,
4317 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4318 Wikipedia: modulo operation</a>.</p>
4319
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4320<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4321 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4322
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4323<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4324 Overflow also leads to undefined behavior; this is a rare case, but can
4325 occur, for example, by taking the remainder of a 32-bit division of
4326 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4327 lets srem be implemented using instructions that return both the result of
4328 the division and the remainder.)</p>
4329
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4330<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4331<pre>
4332 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4333</pre>
4334
4335</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4337<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4338<h4>
4339 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4340</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4341
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4342<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4343
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4344<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4345<pre>
4346 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4347</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4348
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4349<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4350<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4351 its two operands.</p>
4352
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4353<h5>Arguments:</h5>
4354<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4356 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4357
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4358<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4359<p>This instruction returns the <i>remainder</i> of a division. The remainder
4360 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4361
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4362<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4363<pre>
4364 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4365</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4366
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4367</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4368
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4369</div>
4370
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4371<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4372<h3>
4373 <a name="bitwiseops">Bitwise Binary Operations</a>
4374</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4376<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4377
4378<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4379 program. They are generally very efficient instructions and can commonly be
4380 strength reduced from other instructions. They require two operands of the
4381 same type, execute an operation on them, and produce a single value. The
4382 resulting value is the same type as its operands.</p>
4383
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4384<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4385<h4>
4386 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4387</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4389<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4390
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4391<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4392<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4393 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4394 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4395 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4396 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4397</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4398
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4399<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4401 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4402
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4403<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4404<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4405 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4406 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4407
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4408<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4409<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4410 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4411 is (statically or dynamically) negative or equal to or larger than the number
4412 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4413 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4414 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4415
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4416<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4417 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattnerf10dfdc2011-02-09 16:44:44 +0000[diff] [blame]4418 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4419 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4420 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4421 they would if the shift were expressed as a mul instruction with the same
4422 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4423
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4424<h5>Example:</h5>
4425<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4426 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4427 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4428 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4429 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4430 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4431</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4432
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4433</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4434
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4435<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4436<h4>
4437 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4438</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4439
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4440<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4441
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4442<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4443<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4444 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4445 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4446</pre>
4447
4448<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4449<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4450 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4451
4452<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4453<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4455 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4456
4457<h5>Semantics:</h5>
4458<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4459 significant bits of the result will be filled with zero bits after the shift.
4460 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4461 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4462 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4463 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4464
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4465<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4466 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4467 shifted out are non-zero.</p>
4468
4469
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4470<h5>Example:</h5>
4471<pre>
4472 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4473 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4474 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4475 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4476 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4477 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4478</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4479
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4480</div>
4481
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4482<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4483<h4>
4484 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4485</h4>
4486
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4487<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4488
4489<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4491 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4492 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4493</pre>
4494
4495<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4496<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4497 operand shifted to the right a specified number of bits with sign
4498 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4499
4500<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4501<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4502 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4503 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4504
4505<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4506<p>This instruction always performs an arithmetic shift right operation, The
4507 most significant bits of the result will be filled with the sign bit
4508 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4509 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4510 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4511 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4512
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4513<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4514 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4515 shifted out are non-zero.</p>
4516
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4517<h5>Example:</h5>
4518<pre>
4519 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4520 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4521 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4522 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4523 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4524 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4525</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4526
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4527</div>
4528
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4529<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4530<h4>
4531 <a name="i_and">'<tt>and</tt>' Instruction</a>
4532</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4533
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4534<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4535
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4536<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4537<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4538 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4539</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4540
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4541<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4543 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4544
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4545<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4546<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4547 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4548 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4550<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4551<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4552
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4553<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4554 <tbody>
4555 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4556 <th>In0</th>
4557 <th>In1</th>
4558 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4559 </tr>
4560 <tr>
4561 <td>0</td>
4562 <td>0</td>
4563 <td>0</td>
4564 </tr>
4565 <tr>
4566 <td>0</td>
4567 <td>1</td>
4568 <td>0</td>
4569 </tr>
4570 <tr>
4571 <td>1</td>
4572 <td>0</td>
4573 <td>0</td>
4574 </tr>
4575 <tr>
4576 <td>1</td>
4577 <td>1</td>
4578 <td>1</td>
4579 </tr>
4580 </tbody>
4581</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4582
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4583<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4584<pre>
4585 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4586 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4587 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4588</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4589</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4590<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4591<h4>
4592 <a name="i_or">'<tt>or</tt>' Instruction</a>
4593</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4594
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4595<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4596
4597<h5>Syntax:</h5>
4598<pre>
4599 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4600</pre>
4601
4602<h5>Overview:</h5>
4603<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4604 two operands.</p>
4605
4606<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4607<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4608 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4609 values. Both arguments must have identical types.</p>
4610
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4611<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4612<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4613
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4614<table border="1" cellspacing="0" cellpadding="4">
4615 <tbody>
4616 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4617 <th>In0</th>
4618 <th>In1</th>
4619 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4620 </tr>
4621 <tr>
4622 <td>0</td>
4623 <td>0</td>
4624 <td>0</td>
4625 </tr>
4626 <tr>
4627 <td>0</td>
4628 <td>1</td>
4629 <td>1</td>
4630 </tr>
4631 <tr>
4632 <td>1</td>
4633 <td>0</td>
4634 <td>1</td>
4635 </tr>
4636 <tr>
4637 <td>1</td>
4638 <td>1</td>
4639 <td>1</td>
4640 </tr>
4641 </tbody>
4642</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4643
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4644<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4645<pre>
4646 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4647 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4648 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4649</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4650
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4651</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4653<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4654<h4>
4655 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4656</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4657
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4658<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4660<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4661<pre>
4662 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4663</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4664
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4665<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4666<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4667 its two operands. The <tt>xor</tt> is used to implement the "one's
4668 complement" operation, which is the "~" operator in C.</p>
4669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4670<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4671<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4673 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4675<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4676<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4678<table border="1" cellspacing="0" cellpadding="4">
4679 <tbody>
4680 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4681 <th>In0</th>
4682 <th>In1</th>
4683 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4684 </tr>
4685 <tr>
4686 <td>0</td>
4687 <td>0</td>
4688 <td>0</td>
4689 </tr>
4690 <tr>
4691 <td>0</td>
4692 <td>1</td>
4693 <td>1</td>
4694 </tr>
4695 <tr>
4696 <td>1</td>
4697 <td>0</td>
4698 <td>1</td>
4699 </tr>
4700 <tr>
4701 <td>1</td>
4702 <td>1</td>
4703 <td>0</td>
4704 </tr>
4705 </tbody>
4706</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4707
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4708<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709<pre>
4710 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4711 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4712 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4713 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4714</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4716</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4718</div>
4719
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4720<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4721<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4722 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4723</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4724
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4725<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4726
4727<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4728 target-independent manner. These instructions cover the element-access and
4729 vector-specific operations needed to process vectors effectively. While LLVM
4730 does directly support these vector operations, many sophisticated algorithms
4731 will want to use target-specific intrinsics to take full advantage of a
4732 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4733
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4734<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4735<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4736 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4737</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4738
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4739<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4740
4741<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4742<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4743 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4744</pre>
4745
4746<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4747<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4748 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4749
4750
4751<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4752<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4753 of <a href="#t_vector">vector</a> type. The second operand is an index
4754 indicating the position from which to extract the element. The index may be
4755 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4756
4757<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4758<p>The result is a scalar of the same type as the element type of
4759 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4760 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4761 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4762
4763<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4764<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4765 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4766</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4767
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4768</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4769
4770<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4771<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4772 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4773</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4774
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4775<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4776
4777<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4778<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4779 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4780</pre>
4781
4782<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4784 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4785
4786<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4787<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4788 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4789 whose type must equal the element type of the first operand. The third
4790 operand is an index indicating the position at which to insert the value.
4791 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4792
4793<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4794<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4795 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4796 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4797 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4798
4799<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4800<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4801 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4802</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4803
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4804</div>
4805
4806<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4807<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4808 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4809</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4811<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4812
4813<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4814<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4815 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4816</pre>
4817
4818<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4819<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4820 from two input vectors, returning a vector with the same element type as the
4821 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4822
4823<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4824<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsbe3d3a62012-06-14 14:58:28 +0000[diff] [blame]4825 with the same type. The third argument is a shuffle mask whose
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4826 element type is always 'i32'. The result of the instruction is a vector
4827 whose length is the same as the shuffle mask and whose element type is the
4828 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4829
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4830<p>The shuffle mask operand is required to be a constant vector with either
4831 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4832
4833<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4834<p>The elements of the two input vectors are numbered from left to right across
4835 both of the vectors. The shuffle mask operand specifies, for each element of
4836 the result vector, which element of the two input vectors the result element
4837 gets. The element selector may be undef (meaning "don't care") and the
4838 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4839
4840<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4841<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4842 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4843 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4844 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4845 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4846 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4847 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4848 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4849 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4850</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4851
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4852</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4853
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4854</div>
4855
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4856<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4857<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4858 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4859</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4860
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4861<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4862
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4863<p>LLVM supports several instructions for working with
4864 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4865
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4866<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4867<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4868 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4869</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4870
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4871<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4872
4873<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4874<pre>
4875 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4876</pre>
4877
4878<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4879<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4880 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4881
4882<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4884 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4885 <a href="#t_array">array</a> type. The operands are constant indices to
4886 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4887 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4888 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4889 <ul>
4890 <li>Since the value being indexed is not a pointer, the first index is
4891 omitted and assumed to be zero.</li>
4892 <li>At least one index must be specified.</li>
4893 <li>Not only struct indices but also array indices must be in
4894 bounds.</li>
4895 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4896
4897<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4898<p>The result is the value at the position in the aggregate specified by the
4899 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4900
4901<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4902<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4903 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4904</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4905
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4906</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4907
4908<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4909<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4910 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4911</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4912
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4913<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4914
4915<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4916<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4917 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt;{, &lt;idx&gt;}* <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4918</pre>
4919
4920<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4921<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4922 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4923
4924<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4925<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4926 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4927 <a href="#t_array">array</a> type. The second operand is a first-class
4928 value to insert. The following operands are constant indices indicating
4929 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4930 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4931 value to insert must have the same type as the value identified by the
4932 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4933
4934<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4935<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4936 that of <tt>val</tt> except that the value at the position specified by the
4937 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4938
4939<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4940<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4941 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4942 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4943 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4945
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4946</div>
4947
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4948</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4949
4950<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4951<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4952 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4953</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4954
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4955<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4956
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4957<p>A key design point of an SSA-based representation is how it represents
4958 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4959 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4960 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4961
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4962<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4963<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4964 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4965</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4966
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4967<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4968
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4969<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4970<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4971 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4972</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4973
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4974<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4975<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4976 currently executing function, to be automatically released when this function
4977 returns to its caller. The object is always allocated in the generic address
4978 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4981<p>The '<tt>alloca</tt>' instruction
4982 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4983 runtime stack, returning a pointer of the appropriate type to the program.
4984 If "NumElements" is specified, it is the number of elements allocated,
4985 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4986 specified, the value result of the allocation is guaranteed to be aligned to
4987 at least that boundary. If not specified, or if zero, the target can choose
4988 to align the allocation on any convenient boundary compatible with the
4989 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4990
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4991<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4992
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4993<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4994<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4996 memory is automatically released when the function returns. The
4997 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4998 variables that must have an address available. When the function returns
4999 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]5000 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]5001 reclaimed. Allocating zero bytes is legal, but the result is undefined.
5002 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewyckyf70a2bd2012-03-18 09:35:50 +0000[diff] [blame]5003 not specified.</p>
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]5004
5005<p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]5006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5007<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]5008<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]5009 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
5010 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
5011 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
5012 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5013</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5015</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]5016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5017<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5018<h4>
5019 <a name="i_load">'<tt>load</tt>' Instruction</a>
5020</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5021
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5022<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5023
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5024<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025<pre>
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]5026 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;][, !invariant.load !&lt;index&gt;]
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]5027 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5028 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5029</pre>
5030
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5031<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5032<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5033
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5034<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5035<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
5036 from which to load. The pointer must point to
5037 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
5038 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]5039 number or order of execution of this <tt>load</tt> with other <a
5040 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5041
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]5042<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
5043 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5044 argument. The <code>release</code> and <code>acq_rel</code> orderings are
5045 not valid on <code>load</code> instructions. Atomic loads produce <a
5046 href="#memorymodel">defined</a> results when they may see multiple atomic
5047 stores. The type of the pointee must be an integer type whose bit width
5048 is a power of two greater than or equal to eight and less than or equal
5049 to a target-specific size limit. <code>align</code> must be explicitly
5050 specified on atomic loads, and the load has undefined behavior if the
5051 alignment is not set to a value which is at least the size in bytes of
5052 the pointee. <code>!nontemporal</code> does not have any defined semantics
5053 for atomic loads.</p>
5054
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5055<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5056 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5057 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5058 alignment for the target. It is the responsibility of the code emitter to
5059 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5060 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5061 produce less efficient code. An alignment of 1 is always safe.</p>
5062
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5063<p>The optional <tt>!nontemporal</tt> metadata must reference a single
5064 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5065 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5066 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
5067 and code generator that this load is not expected to be reused in the cache.
5068 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5069 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5070
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]5071<p>The optional <tt>!invariant.load</tt> metadata must reference a single
5072 metatadata name &lt;index&gt; corresponding to a metadata node with no
5073 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
5074 instruction tells the optimizer and code generator that this load address
5075 points to memory which does not change value during program execution.
5076 The optimizer may then move this load around, for example, by hoisting it
5077 out of loops using loop invariant code motion.</p>
5078
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5079<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080<p>The location of memory pointed to is loaded. If the value being loaded is of
5081 scalar type then the number of bytes read does not exceed the minimum number
5082 of bytes needed to hold all bits of the type. For example, loading an
5083 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5084 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5085 is undefined if the value was not originally written using a store of the
5086 same type.</p>
5087
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5088<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089<pre>
5090 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5091 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5092 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5093</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5094
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5095</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5097<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5098<h4>
5099 <a name="i_store">'<tt>store</tt>' Instruction</a>
5100</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5102<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5103
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5104<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5105<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5106 store [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
5107 store atomic [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5108</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5109
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5110<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5111<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5112
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5113<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5114<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5115 and an address at which to store it. The type of the
5116 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5117 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]5118 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5119 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5120 order of execution of this <tt>store</tt> with other <a
5121 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5122
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]5123<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5124 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5125 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5126 valid on <code>store</code> instructions. Atomic loads produce <a
5127 href="#memorymodel">defined</a> results when they may see multiple atomic
5128 stores. The type of the pointee must be an integer type whose bit width
5129 is a power of two greater than or equal to eight and less than or equal
5130 to a target-specific size limit. <code>align</code> must be explicitly
5131 specified on atomic stores, and the store has undefined behavior if the
5132 alignment is not set to a value which is at least the size in bytes of
5133 the pointee. <code>!nontemporal</code> does not have any defined semantics
5134 for atomic stores.</p>
5135
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5136<p>The optional constant "align" argument specifies the alignment of the
5137 operation (that is, the alignment of the memory address). A value of 0 or an
5138 omitted "align" argument means that the operation has the preferential
5139 alignment for the target. It is the responsibility of the code emitter to
5140 ensure that the alignment information is correct. Overestimating the
5141 alignment results in an undefined behavior. Underestimating the alignment may
5142 produce less efficient code. An alignment of 1 is always safe.</p>
5143
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5144<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5145 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5146 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5147 instruction tells the optimizer and code generator that this load is
5148 not expected to be reused in the cache. The code generator may
5149 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5150 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5151
5152
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5153<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5154<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5155 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5156 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5157 does not exceed the minimum number of bytes needed to hold all bits of the
5158 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5159 writing a value of a type like <tt>i20</tt> with a size that is not an
5160 integral number of bytes, it is unspecified what happens to the extra bits
5161 that do not belong to the type, but they will typically be overwritten.</p>
5162
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5163<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5164<pre>
5165 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]5166 store i32 3, i32* %ptr <i>; yields {void}</i>
5167 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5168</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5170</div>
5171
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5173<h4>
5174<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5175</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5176
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5177<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5178
5179<h5>Syntax:</h5>
5180<pre>
5181 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5182</pre>
5183
5184<h5>Overview:</h5>
5185<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5186between operations.</p>
5187
5188<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5189href="#ordering">ordering</a> argument which defines what
5190<i>synchronizes-with</i> edges they add. They can only be given
5191<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5192<code>seq_cst</code> orderings.</p>
5193
5194<h5>Semantics:</h5>
5195<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5196semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5197<code>acquire</code> ordering semantics if and only if there exist atomic
5198operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5199<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5200<var>X</var> modifies <var>M</var> (either directly or through some side effect
5201of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5202<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5203<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5204than an explicit <code>fence</code>, one (but not both) of the atomic operations
5205<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5206<code>acquire</code> (resp.) ordering constraint and still
5207<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5208<i>happens-before</i> edge.</p>
5209
5210<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5211having both <code>acquire</code> and <code>release</code> semantics specified
5212above, participates in the global program order of other <code>seq_cst</code>
5213operations and/or fences.</p>
5214
5215<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5216specifies that the fence only synchronizes with other fences in the same
5217thread. (This is useful for interacting with signal handlers.)</p>
5218
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5219<h5>Example:</h5>
5220<pre>
5221 fence acquire <i>; yields {void}</i>
5222 fence singlethread seq_cst <i>; yields {void}</i>
5223</pre>
5224
5225</div>
5226
5227<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5228<h4>
5229<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5230</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5231
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5232<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5233
5234<h5>Syntax:</h5>
5235<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5236 cmpxchg [volatile] &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;cmp&gt;, &lt;ty&gt; &lt;new&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5237</pre>
5238
5239<h5>Overview:</h5>
5240<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5241It loads a value in memory and compares it to a given value. If they are
5242equal, it stores a new value into the memory.</p>
5243
5244<h5>Arguments:</h5>
5245<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5246address to operate on, a value to compare to the value currently be at that
5247address, and a new value to place at that address if the compared values are
5248equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5249bit width is a power of two greater than or equal to eight and less than
5250or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5251'<var>&lt;new&gt;</var>' must have the same type, and the type of
5252'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5253<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5254optimizer is not allowed to modify the number or order of execution
5255of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5256operations</a>.</p>
5257
5258<!-- FIXME: Extend allowed types. -->
5259
5260<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5261<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5262
5263<p>The optional "<code>singlethread</code>" argument declares that the
5264<code>cmpxchg</code> is only atomic with respect to code (usually signal
5265handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5266cmpxchg is atomic with respect to all other code in the system.</p>
5267
5268<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5269the size in memory of the operand.
5270
5271<h5>Semantics:</h5>
5272<p>The contents of memory at the location specified by the
5273'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5274'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5275'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5276is returned.
5277
5278<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5279purpose of identifying <a href="#release_sequence">release sequences</a>. A
5280failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5281parameter determined by dropping any <code>release</code> part of the
5282<code>cmpxchg</code>'s ordering.</p>
5283
5284<!--
5285FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5286optimization work on ARM.)
5287
5288FIXME: Is a weaker ordering constraint on failure helpful in practice?
5289-->
5290
5291<h5>Example:</h5>
5292<pre>
5293entry:
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5294 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5295 <a href="#i_br">br</a> label %loop
5296
5297loop:
5298 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5299 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5300 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5301 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5302 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5303
5304done:
5305 ...
5306</pre>
5307
5308</div>
5309
5310<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5311<h4>
5312<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5313</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5314
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5315<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5316
5317<h5>Syntax:</h5>
5318<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]5319 atomicrmw [volatile] &lt;operation&gt; &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;value&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5320</pre>
5321
5322<h5>Overview:</h5>
5323<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5324
5325<h5>Arguments:</h5>
5326<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5327operation to apply, an address whose value to modify, an argument to the
5328operation. The operation must be one of the following keywords:</p>
5329<ul>
5330 <li>xchg</li>
5331 <li>add</li>
5332 <li>sub</li>
5333 <li>and</li>
5334 <li>nand</li>
5335 <li>or</li>
5336 <li>xor</li>
5337 <li>max</li>
5338 <li>min</li>
5339 <li>umax</li>
5340 <li>umin</li>
5341</ul>
5342
5343<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5344bit width is a power of two greater than or equal to eight and less than
5345or equal to a target-specific size limit. The type of the
5346'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5347If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5348optimizer is not allowed to modify the number or order of execution of this
5349<code>atomicrmw</code> with other <a href="#volatile">volatile
5350 operations</a>.</p>
5351
5352<!-- FIXME: Extend allowed types. -->
5353
5354<h5>Semantics:</h5>
5355<p>The contents of memory at the location specified by the
5356'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5357back. The original value at the location is returned. The modification is
5358specified by the <var>operation</var> argument:</p>
5359
5360<ul>
5361 <li>xchg: <code>*ptr = val</code></li>
5362 <li>add: <code>*ptr = *ptr + val</code></li>
5363 <li>sub: <code>*ptr = *ptr - val</code></li>
5364 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5365 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5366 <li>or: <code>*ptr = *ptr | val</code></li>
5367 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5368 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5369 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5370 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5371 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5372</ul>
5373
5374<h5>Example:</h5>
5375<pre>
5376 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5377</pre>
5378
5379</div>
5380
5381<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5382<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5383 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5384</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5385
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5386<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5387
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5388<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5389<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5390 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5391 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5392 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5393</pre>
5394
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5395<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5396<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5397 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5398 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5399
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5400<h5>Arguments:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5401<p>The first argument is always a pointer or a vector of pointers,
5402 and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5403 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5404 elements of the aggregate object are indexed. The interpretation of each
5405 index is dependent on the type being indexed into. The first index always
5406 indexes the pointer value given as the first argument, the second index
5407 indexes a value of the type pointed to (not necessarily the value directly
5408 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5409 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5410 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5411 can never be pointers, since that would require loading the pointer before
5412 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5413
5414<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5415 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5416 integer <b>constants</b> are allowed. When indexing into an array, pointer
5417 or vector, integers of any width are allowed, and they are not required to be
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5418 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5419
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5420<p>For example, let's consider a C code fragment and how it gets compiled to
5421 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5422
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5423<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5424struct RT {
5425 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5426 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5427 char C;
5428};
5429struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5430 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5431 double Y;
5432 struct RT Z;
5433};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5434
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5435int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5436 return &amp;s[1].Z.B[5][13];
5437}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5438</pre>
5439
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5440<p>The LLVM code generated by Clang is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5441
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5442<pre class="doc_code">
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5443%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5444%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5445
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5446define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5447entry:
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5448 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5449 ret i32* %arrayidx
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5450}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5451</pre>
5452
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5453<h5>Semantics:</h5>
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5454<p>In the example above, the first index is indexing into the
5455 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5456 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5457 structure. The second index indexes into the third element of the structure,
5458 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5459 type, another structure. The third index indexes into the second element of
5460 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5461 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5462 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5463 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5464
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5465<p>Note that it is perfectly legal to index partially through a structure,
5466 returning a pointer to an inner element. Because of this, the LLVM code for
5467 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5468
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5469<pre class="doc_code">
5470define i32* @foo(%struct.ST* %s) {
5471 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5472 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5473 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5474 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5475 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5476 ret i32* %t5
5477}
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5478</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5479
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5480<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]5481 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5482 base pointer is not an <i>in bounds</i> address of an allocated object,
5483 or if any of the addresses that would be formed by successive addition of
5484 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5485 precise signed arithmetic are not an <i>in bounds</i> address of that
5486 allocated object. The <i>in bounds</i> addresses for an allocated object
5487 are all the addresses that point into the object, plus the address one
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5488 byte past the end.
5489 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5490 applies to each of the computations element-wise. </p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5491
5492<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5493 the base address with silently-wrapping two's complement arithmetic. If the
5494 offsets have a different width from the pointer, they are sign-extended or
5495 truncated to the width of the pointer. The result value of the
5496 <tt>getelementptr</tt> may be outside the object pointed to by the base
5497 pointer. The result value may not necessarily be used to access memory
5498 though, even if it happens to point into allocated storage. See the
5499 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5500 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5501
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5502<p>The getelementptr instruction is often confusing. For some more insight into
5503 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5504
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5505<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5506<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5507 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5508 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5509 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5510 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5511 <i>; yields i8*:eptr</i>
5512 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5513 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5514 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5515</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5516
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5517<p>In cases where the pointer argument is a vector of pointers, only a
5518 single index may be used, and the number of vector elements has to be
5519 the same. For example: </p>
5520<pre class="doc_code">
5521 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5522</pre>
5523
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5524</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5525
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5526</div>
5527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5528<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5529<h3>
5530 <a name="convertops">Conversion Operations</a>
5531</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5532
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5533<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5534
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5535<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5536 which all take a single operand and a type. They perform various bit
5537 conversions on the operand.</p>
5538
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5539<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5540<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5541 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5542</h4>
5543
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5544<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5545
5546<h5>Syntax:</h5>
5547<pre>
5548 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5549</pre>
5550
5551<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5552<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5553 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5554
5555<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5556<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5557 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5558 of the same number of integers.
5559 The bit size of the <tt>value</tt> must be larger than
5560 the bit size of the destination type, <tt>ty2</tt>.
5561 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5562
5563<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5565 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5566 source size must be larger than the destination size, <tt>trunc</tt> cannot
5567 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5568
5569<h5>Example:</h5>
5570<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5571 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5572 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5573 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5574 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5575</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5576
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5577</div>
5578
5579<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5580<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5581 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5582</h4>
5583
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5584<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5585
5586<h5>Syntax:</h5>
5587<pre>
5588 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5589</pre>
5590
5591<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5592<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5593 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5594
5595
5596<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5597<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5598 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5599 of the same number of integers.
5600 The bit size of the <tt>value</tt> must be smaller than
5601 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5602 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5603
5604<h5>Semantics:</h5>
5605<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5607
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5608<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5609
5610<h5>Example:</h5>
5611<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5612 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5613 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5614 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5615</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5616
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5617</div>
5618
5619<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5620<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5621 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5622</h4>
5623
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5624<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5625
5626<h5>Syntax:</h5>
5627<pre>
5628 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5629</pre>
5630
5631<h5>Overview:</h5>
5632<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5633
5634<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5635<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5636 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5637 of the same number of integers.
5638 The bit size of the <tt>value</tt> must be smaller than
5639 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5640 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5641
5642<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5643<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5644 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5645 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5646
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5647<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5648
5649<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5650<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5651 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5652 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5653 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5654</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5656</div>
5657
5658<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5659<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5660 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5661</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5662
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5663<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5664
5665<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5666<pre>
5667 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5668</pre>
5669
5670<h5>Overview:</h5>
5671<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5672 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5673
5674<h5>Arguments:</h5>
5675<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5676 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5677 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5678 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5679 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5680
5681<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5682<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5683 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5684 <a href="#t_floating">floating point</a> type. If the value cannot fit
5685 within the destination type, <tt>ty2</tt>, then the results are
5686 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5687
5688<h5>Example:</h5>
5689<pre>
5690 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5691 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5692</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5693
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5694</div>
5695
5696<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5697<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5698 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5699</h4>
5700
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5701<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5702
5703<h5>Syntax:</h5>
5704<pre>
5705 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5706</pre>
5707
5708<h5>Overview:</h5>
5709<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5710 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5711
5712<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5713<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5714 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5715 a <a href="#t_floating">floating point</a> type to cast it to. The source
5716 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5717
5718<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5719<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5720 <a href="#t_floating">floating point</a> type to a larger
5721 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5722 used to make a <i>no-op cast</i> because it always changes bits. Use
5723 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5724
5725<h5>Example:</h5>
5726<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5727 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5728 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5729</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5730
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5731</div>
5732
5733<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5734<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5735 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5736</h4>
5737
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5738<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5739
5740<h5>Syntax:</h5>
5741<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5742 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5743</pre>
5744
5745<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5746<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5747 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5748
5749<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5750<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5751 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5752 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5753 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5754 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5755
5756<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5757<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5758 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5759 towards zero) unsigned integer value. If the value cannot fit
5760 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5761
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5762<h5>Example:</h5>
5763<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5764 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5765 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5766 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5767</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5768
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5769</div>
5770
5771<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5772<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5773 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5774</h4>
5775
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5776<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5777
5778<h5>Syntax:</h5>
5779<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5780 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5781</pre>
5782
5783<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5784<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5785 <a href="#t_floating">floating point</a> <tt>value</tt> to
5786 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5787
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5788<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5789<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5790 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5791 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5792 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5793 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5794
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5795<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5796<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5797 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5798 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5799 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5800
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5801<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5802<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5803 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5804 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5805 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5806</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5807
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5808</div>
5809
5810<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5811<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5812 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5813</h4>
5814
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5815<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5816
5817<h5>Syntax:</h5>
5818<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5819 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5820</pre>
5821
5822<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5823<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5824 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5825
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5826<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5827<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5828 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5829 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5830 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5831 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5832
5833<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5834<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5835 integer quantity and converts it to the corresponding floating point
5836 value. If the value cannot fit in the floating point value, the results are
5837 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5838
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5839<h5>Example:</h5>
5840<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5841 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5842 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5843</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5845</div>
5846
5847<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5848<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5849 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5850</h4>
5851
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5852<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5853
5854<h5>Syntax:</h5>
5855<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5856 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5857</pre>
5858
5859<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5860<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5861 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5862
5863<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5864<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5866 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5867 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5868 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5871<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5872 quantity and converts it to the corresponding floating point value. If the
5873 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5874
5875<h5>Example:</h5>
5876<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5877 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5878 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5879</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5881</div>
5882
5883<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5884<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5885 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5886</h4>
5887
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5888<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5889
5890<h5>Syntax:</h5>
5891<pre>
5892 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5893</pre>
5894
5895<h5>Overview:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5896<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5897 pointers <tt>value</tt> to
5898 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5899
5900<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5901<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5902 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5903 pointers, and a type to cast it to
5904 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5905 of integers type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5906
5907<h5>Semantics:</h5>
5908<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5909 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5910 truncating or zero extending that value to the size of the integer type. If
5911 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5912 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5913 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5914 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5915
5916<h5>Example:</h5>
5917<pre>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5918 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5919 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5920 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5921</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5922
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5923</div>
5924
5925<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5926<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5927 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5928</h4>
5929
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5930<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5931
5932<h5>Syntax:</h5>
5933<pre>
5934 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5935</pre>
5936
5937<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5938<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5939 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5940
5941<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5942<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943 value to cast, and a type to cast it to, which must be a
5944 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5945
5946<h5>Semantics:</h5>
5947<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5948 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5949 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5950 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5951 than the size of a pointer then a zero extension is done. If they are the
5952 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5953
5954<h5>Example:</h5>
5955<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5956 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5957 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5958 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5959 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5960</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5961
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5962</div>
5963
5964<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5965<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5966 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5967</h4>
5968
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5969<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5970
5971<h5>Syntax:</h5>
5972<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5973 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5974</pre>
5975
5976<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5977<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5978 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5979
5980<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5982 non-aggregate first class value, and a type to cast it to, which must also be
5983 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5984 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5985 identical. If the source type is a pointer, the destination type must also be
5986 a pointer. This instruction supports bitwise conversion of vectors to
5987 integers and to vectors of other types (as long as they have the same
5988 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5991<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5992 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5993 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5994 stored to memory and read back as type <tt>ty2</tt>.
5995 Pointer (or vector of pointers) types may only be converted to other pointer
5996 (or vector of pointers) types with this instruction. To convert
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5997 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5998 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5999
6000<h5>Example:</h5>
6001<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6002 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6003 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]6004 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
6005 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]6006</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6008</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6009
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6010</div>
6011
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6012<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6013<h3>
6014 <a name="otherops">Other Operations</a>
6015</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6016
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6017<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6018
6019<p>The instructions in this category are the "miscellaneous" instructions, which
6020 defy better classification.</p>
6021
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6022<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6023<h4>
6024 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
6025</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6026
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6027<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6029<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6030<pre>
6031 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6032</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6033
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6034<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]6036 boolean values based on comparison of its two integer, integer vector,
6037 pointer, or pointer vector operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6039<h5>Arguments:</h5>
6040<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6041 the condition code indicating the kind of comparison to perform. It is not a
6042 value, just a keyword. The possible condition code are:</p>
6043
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6044<ol>
6045 <li><tt>eq</tt>: equal</li>
6046 <li><tt>ne</tt>: not equal </li>
6047 <li><tt>ugt</tt>: unsigned greater than</li>
6048 <li><tt>uge</tt>: unsigned greater or equal</li>
6049 <li><tt>ult</tt>: unsigned less than</li>
6050 <li><tt>ule</tt>: unsigned less or equal</li>
6051 <li><tt>sgt</tt>: signed greater than</li>
6052 <li><tt>sge</tt>: signed greater or equal</li>
6053 <li><tt>slt</tt>: signed less than</li>
6054 <li><tt>sle</tt>: signed less or equal</li>
6055</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6056
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]6057<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6058 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
6059 typed. They must also be identical types.</p>
6060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6061<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
6063 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6064 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6065 result, as follows:</p>
6066
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6067<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6068 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6069 <tt>false</tt> otherwise. No sign interpretation is necessary or
6070 performed.</li>
6071
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6072 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6073 <tt>false</tt> otherwise. No sign interpretation is necessary or
6074 performed.</li>
6075
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6076 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6077 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6078
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6079 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6080 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6081 to <tt>op2</tt>.</li>
6082
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6083 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6084 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6085
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6086 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6087 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6088
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6089 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6090 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6091
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6092 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6093 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6094 to <tt>op2</tt>.</li>
6095
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6096 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6097 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6098
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6099 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6100 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6101</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6102
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6103<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6104 values are compared as if they were integers.</p>
6105
6106<p>If the operands are integer vectors, then they are compared element by
6107 element. The result is an <tt>i1</tt> vector with the same number of elements
6108 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6109
6110<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6111<pre>
6112 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6113 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6114 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6115 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6116 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6117 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6118</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6119
6120<p>Note that the code generator does not yet support vector types with
6121 the <tt>icmp</tt> instruction.</p>
6122
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6123</div>
6124
6125<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6126<h4>
6127 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6128</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6130<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6131
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6132<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6133<pre>
6134 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6135</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6136
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6137<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6138<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6139 values based on comparison of its operands.</p>
6140
6141<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6142(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6143
6144<p>If the operands are floating point vectors, then the result type is a vector
6145 of boolean with the same number of elements as the operands being
6146 compared.</p>
6147
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6148<h5>Arguments:</h5>
6149<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6150 the condition code indicating the kind of comparison to perform. It is not a
6151 value, just a keyword. The possible condition code are:</p>
6152
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6153<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6154 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6155 <li><tt>oeq</tt>: ordered and equal</li>
6156 <li><tt>ogt</tt>: ordered and greater than </li>
6157 <li><tt>oge</tt>: ordered and greater than or equal</li>
6158 <li><tt>olt</tt>: ordered and less than </li>
6159 <li><tt>ole</tt>: ordered and less than or equal</li>
6160 <li><tt>one</tt>: ordered and not equal</li>
6161 <li><tt>ord</tt>: ordered (no nans)</li>
6162 <li><tt>ueq</tt>: unordered or equal</li>
6163 <li><tt>ugt</tt>: unordered or greater than </li>
6164 <li><tt>uge</tt>: unordered or greater than or equal</li>
6165 <li><tt>ult</tt>: unordered or less than </li>
6166 <li><tt>ule</tt>: unordered or less than or equal</li>
6167 <li><tt>une</tt>: unordered or not equal</li>
6168 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6169 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6170</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6171
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6172<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6173 <i>unordered</i> means that either operand may be a QNAN.</p>
6174
6175<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6176 a <a href="#t_floating">floating point</a> type or
6177 a <a href="#t_vector">vector</a> of floating point type. They must have
6178 identical types.</p>
6179
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6180<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]6181<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6182 according to the condition code given as <tt>cond</tt>. If the operands are
6183 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6184 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6185 follows:</p>
6186
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6187<ol>
6188 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6189
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6190 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6191 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6192
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6193 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6194 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6195
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6196 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6197 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6199 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6200 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6201
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6202 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6203 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6204
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6205 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6206 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6207
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6208 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6209
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6210 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6211 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6212
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6213 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6214 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6215
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6216 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6217 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6218
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6219 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6220 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6221
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6222 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6223 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6224
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6225 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6226 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6227
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6228 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6229
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6230 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6231</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6232
6233<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<pre>
6235 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6236 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6237 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6238 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6239</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6240
6241<p>Note that the code generator does not yet support vector types with
6242 the <tt>fcmp</tt> instruction.</p>
6243
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6244</div>
6245
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6246<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6247<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6248 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6249</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6250
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6251<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6252
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6253<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6254<pre>
6255 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6256</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6257
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6258<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6259<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6260 SSA graph representing the function.</p>
6261
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6262<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6263<p>The type of the incoming values is specified with the first type field. After
6264 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6265 one pair for each predecessor basic block of the current block. Only values
6266 of <a href="#t_firstclass">first class</a> type may be used as the value
6267 arguments to the PHI node. Only labels may be used as the label
6268 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6269
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6270<p>There must be no non-phi instructions between the start of a basic block and
6271 the PHI instructions: i.e. PHI instructions must be first in a basic
6272 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6273
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6274<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6275 occur on the edge from the corresponding predecessor block to the current
6276 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6277 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]6278
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6279<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6280<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6281 specified by the pair corresponding to the predecessor basic block that
6282 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6283
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6284<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6285<pre>
6286Loop: ; Infinite loop that counts from 0 on up...
6287 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6288 %nextindvar = add i32 %indvar, 1
6289 br label %Loop
6290</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6292</div>
6293
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6294<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6295<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6296 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6297</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6298
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6299<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6300
6301<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6302<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6303 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
6304
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6305 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6306</pre>
6307
6308<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6309<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6310 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6311
6312
6313<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6314<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6315 values indicating the condition, and two values of the
6316 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6317 vectors and the condition is a scalar, then entire vectors are selected, not
6318 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6319
6320<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6321<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6322 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6323
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6324<p>If the condition is a vector of i1, then the value arguments must be vectors
6325 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6326
6327<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6328<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]6329 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6330</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6331
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6332</div>
6333
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]6334<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6335<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6336 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6337</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6338
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6339<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6340
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6341<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6342<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6343 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6344</pre>
6345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6346<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6347<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6348
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6349<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6350<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6351
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6352<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6353 <li>The optional "tail" marker indicates that the callee function does not
6354 access any allocas or varargs in the caller. Note that calls may be
6355 marked "tail" even if they do not occur before
6356 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6357 present, the function call is eligible for tail call optimization,
6358 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6359 optimized into a jump</a>. The code generator may optimize calls marked
6360 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6361 sibling call optimization</a> when the caller and callee have
6362 matching signatures, or 2) forced tail call optimization when the
6363 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6364 <ul>
6365 <li>Caller and callee both have the calling
6366 convention <tt>fastcc</tt>.</li>
6367 <li>The call is in tail position (ret immediately follows call and ret
6368 uses value of call or is void).</li>
6369 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6370 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6371 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6372 constraints are met.</a></li>
6373 </ul>
6374 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6375
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6376 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6377 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6378 defaults to using C calling conventions. The calling convention of the
6379 call must match the calling convention of the target function, or else the
6380 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6381
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6382 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6383 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6384 '<tt>inreg</tt>' attributes are valid here.</li>
6385
6386 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6387 type of the return value. Functions that return no value are marked
6388 <tt><a href="#t_void">void</a></tt>.</li>
6389
6390 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6391 being invoked. The argument types must match the types implied by this
6392 signature. This type can be omitted if the function is not varargs and if
6393 the function type does not return a pointer to a function.</li>
6394
6395 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6396 be invoked. In most cases, this is a direct function invocation, but
6397 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6398 to function value.</li>
6399
6400 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6401 signature argument types and parameter attributes. All arguments must be
6402 of <a href="#t_firstclass">first class</a> type. If the function
6403 signature indicates the function accepts a variable number of arguments,
6404 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6405
6406 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6407 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6408 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6409</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6410
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6411<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6412<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6413 a specified function, with its incoming arguments bound to the specified
6414 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6415 function, control flow continues with the instruction after the function
6416 call, and the return value of the function is bound to the result
6417 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6419<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6420<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6421 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6422 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6423 %X = tail call i32 @foo() <i>; yields i32</i>
6424 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6425 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6426
6427 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6428 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6429 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6430 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6431 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6432 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6433</pre>
6434
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6435<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6436standard C99 library as being the C99 library functions, and may perform
6437optimizations or generate code for them under that assumption. This is
6438something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6439freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6440
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6441</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6442
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6443<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6444<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6445 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6446</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6447
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6448<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6449
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6450<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6451<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6452 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6453</pre>
6454
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6455<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6456<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6457 the "variable argument" area of a function call. It is used to implement the
6458 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6459
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6460<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6461<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6462 argument. It returns a value of the specified argument type and increments
6463 the <tt>va_list</tt> to point to the next argument. The actual type
6464 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6465
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6466<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6467<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6468 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6469 to the next argument. For more information, see the variable argument
6470 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6471
6472<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6473 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6474 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6475
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6476<p><tt>va_arg</tt> is an LLVM instruction instead of
6477 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6478 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6479
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6480<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6481<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6482
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6483<p>Note that the code generator does not yet fully support va_arg on many
6484 targets. Also, it does not currently support va_arg with aggregate types on
6485 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6486
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6487</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6488
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6489<!-- _______________________________________________________________________ -->
6490<h4>
6491 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6492</h4>
6493
6494<div>
6495
6496<h5>Syntax:</h5>
6497<pre>
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6498 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6499 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6500
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6501 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6502 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6503</pre>
6504
6505<h5>Overview:</h5>
6506<p>The '<tt>landingpad</tt>' instruction is used by
6507 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6508 system</a> to specify that a basic block is a landing pad &mdash; one where
6509 the exception lands, and corresponds to the code found in the
6510 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6511 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6512 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6513 type <tt>resultty</tt>.</p>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6514
6515<h5>Arguments:</h5>
6516<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6517 function associated with the unwinding mechanism. The optional
6518 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6519
6520<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6521 or <tt>filter</tt> &mdash; and contains the global variable representing the
6522 "type" that may be caught or filtered respectively. Unlike the
6523 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6524 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6525 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6526 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6527
6528<h5>Semantics:</h5>
6529<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6530 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6531 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6532 calling conventions, how the personality function results are represented in
6533 LLVM IR is target specific.</p>
6534
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6535<p>The clauses are applied in order from top to bottom. If two
6536 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6537 clauses from the calling function are appended to the list of clauses.
6538 When the call stack is being unwound due to an exception being thrown, the
6539 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6540 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6541 unwinding continues further up the call stack.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6542
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6543<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6544
6545<ul>
6546 <li>A landing pad block is a basic block which is the unwind destination of an
6547 '<tt>invoke</tt>' instruction.</li>
6548 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6549 first non-PHI instruction.</li>
6550 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6551 pad block.</li>
6552 <li>A basic block that is not a landing pad block may not include a
6553 '<tt>landingpad</tt>' instruction.</li>
6554 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6555 personality function.</li>
6556</ul>
6557
6558<h5>Example:</h5>
6559<pre>
6560 ;; A landing pad which can catch an integer.
6561 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6562 catch i8** @_ZTIi
6563 ;; A landing pad that is a cleanup.
6564 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6565 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6566 ;; A landing pad which can catch an integer and can only throw a double.
6567 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6568 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6569 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6570</pre>
6571
6572</div>
6573
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6574</div>
6575
6576</div>
6577
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6578<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6579<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6580<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6581
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6582<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6583
6584<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6585 well known names and semantics and are required to follow certain
6586 restrictions. Overall, these intrinsics represent an extension mechanism for
6587 the LLVM language that does not require changing all of the transformations
6588 in LLVM when adding to the language (or the bitcode reader/writer, the
6589 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6590
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6591<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6592 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6593 begin with this prefix. Intrinsic functions must always be external
6594 functions: you cannot define the body of intrinsic functions. Intrinsic
6595 functions may only be used in call or invoke instructions: it is illegal to
6596 take the address of an intrinsic function. Additionally, because intrinsic
6597 functions are part of the LLVM language, it is required if any are added that
6598 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6599
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6600<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6601 family of functions that perform the same operation but on different data
6602 types. Because LLVM can represent over 8 million different integer types,
6603 overloading is used commonly to allow an intrinsic function to operate on any
6604 integer type. One or more of the argument types or the result type can be
6605 overloaded to accept any integer type. Argument types may also be defined as
6606 exactly matching a previous argument's type or the result type. This allows
6607 an intrinsic function which accepts multiple arguments, but needs all of them
6608 to be of the same type, to only be overloaded with respect to a single
6609 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6610
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6611<p>Overloaded intrinsics will have the names of its overloaded argument types
6612 encoded into its function name, each preceded by a period. Only those types
6613 which are overloaded result in a name suffix. Arguments whose type is matched
6614 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6615 can take an integer of any width and returns an integer of exactly the same
6616 integer width. This leads to a family of functions such as
6617 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6618 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6619 suffix is required. Because the argument's type is matched against the return
6620 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6621
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6622<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6623 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6624
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6625<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6626<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6627 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6628</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6629
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6630<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6631
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632<p>Variable argument support is defined in LLVM with
6633 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6634 intrinsic functions. These functions are related to the similarly named
6635 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6636
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637<p>All of these functions operate on arguments that use a target-specific value
6638 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6639 not define what this type is, so all transformations should be prepared to
6640 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6641
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6642<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6643 instruction and the variable argument handling intrinsic functions are
6644 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6645
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6646<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6647define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6648 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6649 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6650 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6651 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6652
6653 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6654 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6655
6656 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6657 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6658 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6659 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6660 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6661
6662 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6663 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6664 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6665}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6666
6667declare void @llvm.va_start(i8*)
6668declare void @llvm.va_copy(i8*, i8*)
6669declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6670</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6671
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6672<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6673<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6674 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6675</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6676
6677
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6678<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6679
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6680<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6681<pre>
6682 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6683</pre>
6684
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6685<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6686<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6687 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6688
6689<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6690<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6691
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6692<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6693<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6694 macro available in C. In a target-dependent way, it initializes
6695 the <tt>va_list</tt> element to which the argument points, so that the next
6696 call to <tt>va_arg</tt> will produce the first variable argument passed to
6697 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6698 need to know the last argument of the function as the compiler can figure
6699 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6700
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6701</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6702
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6703<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6704<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6705 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6706</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6707
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6708<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6709
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6710<h5>Syntax:</h5>
6711<pre>
6712 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6713</pre>
6714
6715<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6716<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6717 which has been initialized previously
6718 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6719 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6720
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6721<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6722<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6723
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6724<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6725<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6726 macro available in C. In a target-dependent way, it destroys
6727 the <tt>va_list</tt> element to which the argument points. Calls
6728 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6729 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6730 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6731
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6732</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6733
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6734<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6735<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6736 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6737</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6738
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6739<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6740
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6741<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6742<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6743 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6744</pre>
6745
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6746<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6747<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6748 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6749
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6750<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6751<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6752 The second argument is a pointer to a <tt>va_list</tt> element to copy
6753 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6754
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6755<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6756<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6757 macro available in C. In a target-dependent way, it copies the
6758 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6759 element. This intrinsic is necessary because
6760 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6761 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6762
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6763</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6764
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6765</div>
6766
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6767<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6768<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6769 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6770</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6771
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6772<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6773
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6774<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6775Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6776intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6777roots on the stack</a>, as well as garbage collector implementations that
6778require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6779barriers. Front-ends for type-safe garbage collected languages should generate
6780these intrinsics to make use of the LLVM garbage collectors. For more details,
6781see <a href="GarbageCollection.html">Accurate Garbage Collection with
6782LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6783
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6784<p>The garbage collection intrinsics only operate on objects in the generic
6785 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6786
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6787<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6788<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6789 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6790</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6791
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6792<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6793
6794<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6795<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6796 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6797</pre>
6798
6799<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6800<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6801 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6802
6803<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6804<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6805 root pointer. The second pointer (which must be either a constant or a
6806 global value address) contains the meta-data to be associated with the
6807 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6808
6809<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6810<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6811 location. At compile-time, the code generator generates information to allow
6812 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6813 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6814 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6815
6816</div>
6817
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6818<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6819<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6820 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6821</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6822
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6823<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6824
6825<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6826<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6827 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6828</pre>
6829
6830<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6831<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6832 locations, allowing garbage collector implementations that require read
6833 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6834
6835<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6836<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6837 allocated from the garbage collector. The first object is a pointer to the
6838 start of the referenced object, if needed by the language runtime (otherwise
6839 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6840
6841<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6842<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6843 instruction, but may be replaced with substantially more complex code by the
6844 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6845 may only be used in a function which <a href="#gc">specifies a GC
6846 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6847
6848</div>
6849
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6850<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6851<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6852 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6853</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6854
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6855<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6856
6857<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6858<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6859 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6860</pre>
6861
6862<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6863<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6864 locations, allowing garbage collector implementations that require write
6865 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6866
6867<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6868<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6869 object to store it to, and the third is the address of the field of Obj to
6870 store to. If the runtime does not require a pointer to the object, Obj may
6871 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6872
6873<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6874<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6875 instruction, but may be replaced with substantially more complex code by the
6876 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6877 may only be used in a function which <a href="#gc">specifies a GC
6878 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6879
6880</div>
6881
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6882</div>
6883
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6884<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6885<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6886 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6887</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6888
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6889<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6890
6891<p>These intrinsics are provided by LLVM to expose special features that may
6892 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6893
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6894<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6895<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6896 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6897</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6898
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6899<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6900
6901<h5>Syntax:</h5>
6902<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6903 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6904</pre>
6905
6906<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6907<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6908 target-specific value indicating the return address of the current function
6909 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6910
6911<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6912<p>The argument to this intrinsic indicates which function to return the address
6913 for. Zero indicates the calling function, one indicates its caller, etc.
6914 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6915
6916<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6917<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6918 indicating the return address of the specified call frame, or zero if it
6919 cannot be identified. The value returned by this intrinsic is likely to be
6920 incorrect or 0 for arguments other than zero, so it should only be used for
6921 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6922
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923<p>Note that calling this intrinsic does not prevent function inlining or other
6924 aggressive transformations, so the value returned may not be that of the
6925 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6926
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6927</div>
6928
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6929<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6930<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6931 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6932</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6933
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6934<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6935
6936<h5>Syntax:</h5>
6937<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6938 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6939</pre>
6940
6941<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6942<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6943 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6944
6945<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946<p>The argument to this intrinsic indicates which function to return the frame
6947 pointer for. Zero indicates the calling function, one indicates its caller,
6948 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6949
6950<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6951<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6952 indicating the frame address of the specified call frame, or zero if it
6953 cannot be identified. The value returned by this intrinsic is likely to be
6954 incorrect or 0 for arguments other than zero, so it should only be used for
6955 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6956
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957<p>Note that calling this intrinsic does not prevent function inlining or other
6958 aggressive transformations, so the value returned may not be that of the
6959 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6960
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6961</div>
6962
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6963<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6964<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6965 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6966</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6967
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6968<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6969
6970<h5>Syntax:</h5>
6971<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6972 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6973</pre>
6974
6975<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6976<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6977 of the function stack, for use
6978 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6979 useful for implementing language features like scoped automatic variable
6980 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6981
6982<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6983<p>This intrinsic returns a opaque pointer value that can be passed
6984 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6985 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6986 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6987 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6988 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6989 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6990
6991</div>
6992
6993<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6994<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6995 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6996</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6997
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6998<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6999
7000<h5>Syntax:</h5>
7001<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7002 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]7003</pre>
7004
7005<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7006<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
7007 the function stack to the state it was in when the
7008 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
7009 executed. This is useful for implementing language features like scoped
7010 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]7011
7012<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7013<p>See the description
7014 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]7015
7016</div>
7017
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]7018<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7019<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7020 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7021</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7022
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7023<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7024
7025<h5>Syntax:</h5>
7026<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]7027 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7028</pre>
7029
7030<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
7032 insert a prefetch instruction if supported; otherwise, it is a noop.
7033 Prefetches have no effect on the behavior of the program but can change its
7034 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7037<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
7038 specifier determining if the fetch should be for a read (0) or write (1),
7039 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]7040 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
7041 specifies whether the prefetch is performed on the data (1) or instruction (0)
7042 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
7043 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7044
7045<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7046<p>This intrinsic does not modify the behavior of the program. In particular,
7047 prefetches cannot trap and do not produce a value. On targets that support
7048 this intrinsic, the prefetch can provide hints to the processor cache for
7049 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]7050
7051</div>
7052
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7053<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7054<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7055 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7056</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7057
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7058<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7059
7060<h5>Syntax:</h5>
7061<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]7062 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7063</pre>
7064
7065<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7066<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
7067 Counter (PC) in a region of code to simulators and other tools. The method
7068 is target specific, but it is expected that the marker will use exported
7069 symbols to transmit the PC of the marker. The marker makes no guarantees
7070 that it will remain with any specific instruction after optimizations. It is
7071 possible that the presence of a marker will inhibit optimizations. The
7072 intended use is to be inserted after optimizations to allow correlations of
7073 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7074
7075<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7076<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7077
7078<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7079<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7080 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7081
7082</div>
7083
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7085<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7086 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7087</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7088
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7089<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7090
7091<h5>Syntax:</h5>
7092<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7093 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7094</pre>
7095
7096<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7098 counter register (or similar low latency, high accuracy clocks) on those
7099 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7100 should map to RPCC. As the backing counters overflow quickly (on the order
7101 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7102
7103<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7104<p>When directly supported, reading the cycle counter should not modify any
7105 memory. Implementations are allowed to either return a application specific
7106 value or a system wide value. On backends without support, this is lowered
7107 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7108
7109</div>
7110
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7111</div>
7112
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7113<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7114<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7115 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7116</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7117
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7118<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7119
7120<p>LLVM provides intrinsics for a few important standard C library functions.
7121 These intrinsics allow source-language front-ends to pass information about
7122 the alignment of the pointer arguments to the code generator, providing
7123 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7124
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7125<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7126<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7127 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7128</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7129
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7130<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7131
7132<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7133<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]7134 integer bit width and for different address spaces. Not all targets support
7135 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7136
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7137<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7138 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7139 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7140 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7141 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7142</pre>
7143
7144<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7145<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7146 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7149 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7150 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7151
7152<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7153
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7154<p>The first argument is a pointer to the destination, the second is a pointer
7155 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7156 number of bytes to copy, the fourth argument is the alignment of the
7157 source and destination locations, and the fifth is a boolean indicating a
7158 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7159
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7160<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7161 then the caller guarantees that both the source and destination pointers are
7162 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7163
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7164<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7165 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7166 The detailed access behavior is not very cleanly specified and it is unwise
7167 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7168
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7169<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7170
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7171<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7172 source location to the destination location, which are not allowed to
7173 overlap. It copies "len" bytes of memory over. If the argument is known to
7174 be aligned to some boundary, this can be specified as the fourth argument,
7175 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7176
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7177</div>
7178
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7179<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7180<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7181 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7182</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7183
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7184<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7185
7186<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7187<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]7188 width and for different address space. Not all targets support all bit
7189 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7190
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7191<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7192 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7193 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7194 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7195 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7196</pre>
7197
7198<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7199<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7200 source location to the destination location. It is similar to the
7201 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7202 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7203
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7204<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7205 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7206 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7207
7208<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7209
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7210<p>The first argument is a pointer to the destination, the second is a pointer
7211 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7212 number of bytes to copy, the fourth argument is the alignment of the
7213 source and destination locations, and the fifth is a boolean indicating a
7214 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7215
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7216<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7217 then the caller guarantees that the source and destination pointers are
7218 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7219
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7220<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7221 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7222 The detailed access behavior is not very cleanly specified and it is unwise
7223 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7224
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7225<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7226
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7227<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7228 source location to the destination location, which may overlap. It copies
7229 "len" bytes of memory over. If the argument is known to be aligned to some
7230 boundary, this can be specified as the fourth argument, otherwise it should
7231 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7232
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7233</div>
7234
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7235<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7236<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7237 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7238</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7239
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7240<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7241
7242<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7243<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7244 width and for different address spaces. However, not all targets support all
7245 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7246
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7247<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7248 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7249 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7250 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7251 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7252</pre>
7253
7254<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7255<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7256 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7258<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7259 intrinsic does not return a value and takes extra alignment/volatile
7260 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7261
7262<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7263<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7264 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7265 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7266 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7267
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7268<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7269 then the caller guarantees that the destination pointer is aligned to that
7270 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7271
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7272<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7273 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7274 The detailed access behavior is not very cleanly specified and it is unwise
7275 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7276
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7277<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7278<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7279 at the destination location. If the argument is known to be aligned to some
7280 boundary, this can be specified as the fourth argument, otherwise it should
7281 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7282
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7283</div>
7284
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7285<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7286<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7287 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7288</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7289
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7290<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7291
7292<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7293<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7294 floating point or vector of floating point type. Not all targets support all
7295 types however.</p>
7296
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7297<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7298 declare float @llvm.sqrt.f32(float %Val)
7299 declare double @llvm.sqrt.f64(double %Val)
7300 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7301 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7302 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7303</pre>
7304
7305<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7306<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7307 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7308 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7309 behavior for negative numbers other than -0.0 (which allows for better
7310 optimization, because there is no need to worry about errno being
7311 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7312
7313<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7314<p>The argument and return value are floating point numbers of the same
7315 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7316
7317<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7318<p>This function returns the sqrt of the specified operand if it is a
7319 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7320
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7321</div>
7322
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7323<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7324<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7325 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7326</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7327
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7328<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7329
7330<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7332 floating point or vector of floating point type. Not all targets support all
7333 types however.</p>
7334
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7335<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7336 declare float @llvm.powi.f32(float %Val, i32 %power)
7337 declare double @llvm.powi.f64(double %Val, i32 %power)
7338 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7339 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7340 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7341</pre>
7342
7343<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7344<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7345 specified (positive or negative) power. The order of evaluation of
7346 multiplications is not defined. When a vector of floating point type is
7347 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7348
7349<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7350<p>The second argument is an integer power, and the first is a value to raise to
7351 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7352
7353<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7354<p>This function returns the first value raised to the second power with an
7355 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7356
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7357</div>
7358
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7360<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7361 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7362</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7364<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7365
7366<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7368 floating point or vector of floating point type. Not all targets support all
7369 types however.</p>
7370
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7371<pre>
7372 declare float @llvm.sin.f32(float %Val)
7373 declare double @llvm.sin.f64(double %Val)
7374 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7375 declare fp128 @llvm.sin.f128(fp128 %Val)
7376 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7377</pre>
7378
7379<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7380<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7381
7382<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7383<p>The argument and return value are floating point numbers of the same
7384 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7385
7386<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387<p>This function returns the sine of the specified operand, returning the same
7388 values as the libm <tt>sin</tt> functions would, and handles error conditions
7389 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7390
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7391</div>
7392
7393<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7394<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7395 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7396</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7397
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7398<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7399
7400<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7401<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7402 floating point or vector of floating point type. Not all targets support all
7403 types however.</p>
7404
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7405<pre>
7406 declare float @llvm.cos.f32(float %Val)
7407 declare double @llvm.cos.f64(double %Val)
7408 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7409 declare fp128 @llvm.cos.f128(fp128 %Val)
7410 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7411</pre>
7412
7413<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7414<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7415
7416<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7417<p>The argument and return value are floating point numbers of the same
7418 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7419
7420<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7421<p>This function returns the cosine of the specified operand, returning the same
7422 values as the libm <tt>cos</tt> functions would, and handles error conditions
7423 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7424
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7425</div>
7426
7427<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7428<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7429 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7430</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7431
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7432<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7433
7434<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7435<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7436 floating point or vector of floating point type. Not all targets support all
7437 types however.</p>
7438
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7439<pre>
7440 declare float @llvm.pow.f32(float %Val, float %Power)
7441 declare double @llvm.pow.f64(double %Val, double %Power)
7442 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7443 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7444 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7445</pre>
7446
7447<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7448<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7449 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7450
7451<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7452<p>The second argument is a floating point power, and the first is a value to
7453 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7454
7455<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7456<p>This function returns the first value raised to the second power, returning
7457 the same values as the libm <tt>pow</tt> functions would, and handles error
7458 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7459
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7460</div>
7461
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7462<!-- _______________________________________________________________________ -->
7463<h4>
7464 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7465</h4>
7466
7467<div>
7468
7469<h5>Syntax:</h5>
7470<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7471 floating point or vector of floating point type. Not all targets support all
7472 types however.</p>
7473
7474<pre>
7475 declare float @llvm.exp.f32(float %Val)
7476 declare double @llvm.exp.f64(double %Val)
7477 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7478 declare fp128 @llvm.exp.f128(fp128 %Val)
7479 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7480</pre>
7481
7482<h5>Overview:</h5>
7483<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7484
7485<h5>Arguments:</h5>
7486<p>The argument and return value are floating point numbers of the same
7487 type.</p>
7488
7489<h5>Semantics:</h5>
7490<p>This function returns the same values as the libm <tt>exp</tt> functions
7491 would, and handles error conditions in the same way.</p>
7492
7493</div>
7494
7495<!-- _______________________________________________________________________ -->
7496<h4>
7497 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7498</h4>
7499
7500<div>
7501
7502<h5>Syntax:</h5>
7503<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7504 floating point or vector of floating point type. Not all targets support all
7505 types however.</p>
7506
7507<pre>
7508 declare float @llvm.log.f32(float %Val)
7509 declare double @llvm.log.f64(double %Val)
7510 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7511 declare fp128 @llvm.log.f128(fp128 %Val)
7512 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7513</pre>
7514
7515<h5>Overview:</h5>
7516<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7517
7518<h5>Arguments:</h5>
7519<p>The argument and return value are floating point numbers of the same
7520 type.</p>
7521
7522<h5>Semantics:</h5>
7523<p>This function returns the same values as the libm <tt>log</tt> functions
7524 would, and handles error conditions in the same way.</p>
7525
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7526</div>
7527
7528<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7529<h4>
7530 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7531</h4>
7532
7533<div>
7534
7535<h5>Syntax:</h5>
7536<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7537 floating point or vector of floating point type. Not all targets support all
7538 types however.</p>
7539
7540<pre>
7541 declare float @llvm.fma.f32(float %a, float %b, float %c)
7542 declare double @llvm.fma.f64(double %a, double %b, double %c)
7543 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7544 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7545 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7546</pre>
7547
7548<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7549<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7550 operation.</p>
7551
7552<h5>Arguments:</h5>
7553<p>The argument and return value are floating point numbers of the same
7554 type.</p>
7555
7556<h5>Semantics:</h5>
7557<p>This function returns the same values as the libm <tt>fma</tt> functions
7558 would.</p>
7559
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7560</div>
7561
Peter Collingbourne2165cf62012-07-03 12:25:40 +0000[diff] [blame]7562<!-- _______________________________________________________________________ -->
7563<h4>
7564 <a name="int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a>
7565</h4>
7566
7567<div>
7568
7569<h5>Syntax:</h5>
7570<p>This is an overloaded intrinsic. You can use <tt>llvm.fabs</tt> on any
7571 floating point or vector of floating point type. Not all targets support all
7572 types however.</p>
7573
7574<pre>
7575 declare float @llvm.fabs.f32(float %Val)
7576 declare double @llvm.fabs.f64(double %Val)
7577 declare x86_fp80 @llvm.fabs.f80(x86_fp80 %Val)
7578 declare fp128 @llvm.fabs.f128(fp128 %Val)
7579 declare ppc_fp128 @llvm.fabs.ppcf128(ppc_fp128 %Val)
7580</pre>
7581
7582<h5>Overview:</h5>
7583<p>The '<tt>llvm.fabs.*</tt>' intrinsics return the absolute value of
7584 the operand.</p>
7585
7586<h5>Arguments:</h5>
7587<p>The argument and return value are floating point numbers of the same
7588 type.</p>
7589
7590<h5>Semantics:</h5>
7591<p>This function returns the same values as the libm <tt>fabs</tt> functions
7592 would, and handles error conditions in the same way.</p>
7593
7594</div>
7595
Dan Gohman0b3d7822012-07-26 17:43:27 +0000[diff] [blame]7596<!-- _______________________________________________________________________ -->
7597<h4>
7598 <a name="int_floor">'<tt>llvm.floor.*</tt>' Intrinsic</a>
7599</h4>
7600
7601<div>
7602
7603<h5>Syntax:</h5>
7604<p>This is an overloaded intrinsic. You can use <tt>llvm.floor</tt> on any
7605 floating point or vector of floating point type. Not all targets support all
7606 types however.</p>
7607
7608<pre>
7609 declare float @llvm.floor.f32(float %Val)
7610 declare double @llvm.floor.f64(double %Val)
7611 declare x86_fp80 @llvm.floor.f80(x86_fp80 %Val)
7612 declare fp128 @llvm.floor.f128(fp128 %Val)
7613 declare ppc_fp128 @llvm.floor.ppcf128(ppc_fp128 %Val)
7614</pre>
7615
7616<h5>Overview:</h5>
7617<p>The '<tt>llvm.floor.*</tt>' intrinsics return the floor of
7618 the operand.</p>
7619
7620<h5>Arguments:</h5>
7621<p>The argument and return value are floating point numbers of the same
7622 type.</p>
7623
7624<h5>Semantics:</h5>
7625<p>This function returns the same values as the libm <tt>floor</tt> functions
7626 would, and handles error conditions in the same way.</p>
7627
7628</div>
7629
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7630</div>
7631
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7632<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7633<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7634 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7635</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7636
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7637<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7638
7639<p>LLVM provides intrinsics for a few important bit manipulation operations.
7640 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7641
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7642<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7643<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7644 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7645</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7646
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7647<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7648
7649<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7650<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7652
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7653<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7654 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7655 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7656 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7657</pre>
7658
7659<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7660<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7661 values with an even number of bytes (positive multiple of 16 bits). These
7662 are useful for performing operations on data that is not in the target's
7663 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7664
7665<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7666<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7667 and low byte of the input i16 swapped. Similarly,
7668 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7669 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7670 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7671 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7672 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7673 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7674
7675</div>
7676
7677<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7678<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7679 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7680</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7681
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7682<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7683
7684<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7685<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7686 width, or on any vector with integer elements. Not all targets support all
7687 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7688
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7689<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7690 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7691 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7692 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7693 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7694 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7695 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7696</pre>
7697
7698<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7699<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7700 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7701
7702<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7703<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7704 integer type, or a vector with integer elements.
7705 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7706
7707<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7708<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7709 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7710
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7711</div>
7712
7713<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7714<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7715 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7716</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7718<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7719
7720<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7721<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7722 integer bit width, or any vector whose elements are integers. Not all
7723 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7724
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7725<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7726 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7727 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7728 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7729 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7730 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7731 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7732</pre>
7733
7734<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7735<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7736 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7737
7738<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7739<p>The first argument is the value to be counted. This argument may be of any
7740 integer type, or a vectory with integer element type. The return type
7741 must match the first argument type.</p>
7742
7743<p>The second argument must be a constant and is a flag to indicate whether the
7744 intrinsic should ensure that a zero as the first argument produces a defined
7745 result. Historically some architectures did not provide a defined result for
7746 zero values as efficiently, and many algorithms are now predicated on
7747 avoiding zero-value inputs.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7748
7749<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7750<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7751 zeros in a variable, or within each element of the vector.
7752 If <tt>src == 0</tt> then the result is the size in bits of the type of
7753 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7754 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7755
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7756</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7757
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7758<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7759<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7760 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7761</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7762
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7763<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7764
7765<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7766<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7767 integer bit width, or any vector of integer elements. Not all targets
7768 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7769
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7770<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7771 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7772 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7773 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7774 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7775 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7776 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7777</pre>
7778
7779<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7780<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7781 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7782
7783<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7784<p>The first argument is the value to be counted. This argument may be of any
7785 integer type, or a vectory with integer element type. The return type
7786 must match the first argument type.</p>
7787
7788<p>The second argument must be a constant and is a flag to indicate whether the
7789 intrinsic should ensure that a zero as the first argument produces a defined
7790 result. Historically some architectures did not provide a defined result for
7791 zero values as efficiently, and many algorithms are now predicated on
7792 avoiding zero-value inputs.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7793
7794<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7795<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7796 zeros in a variable, or within each element of a vector.
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7797 If <tt>src == 0</tt> then the result is the size in bits of the type of
7798 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7799 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7800
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7801</div>
7802
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7803</div>
7804
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7805<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7806<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7807 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7808</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7809
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7810<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7811
7812<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7813
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7814<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7815<h4>
7816 <a name="int_sadd_overflow">
7817 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7818 </a>
7819</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7820
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7821<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7822
7823<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7824<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7825 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7826
7827<pre>
7828 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7829 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7830 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7831</pre>
7832
7833<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7834<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7835 a signed addition of the two arguments, and indicate whether an overflow
7836 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7837
7838<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7839<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7840 be of integer types of any bit width, but they must have the same bit
7841 width. The second element of the result structure must be of
7842 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7843 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7844
7845<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7846<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7847 a signed addition of the two variables. They return a structure &mdash; the
7848 first element of which is the signed summation, and the second element of
7849 which is a bit specifying if the signed summation resulted in an
7850 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7851
7852<h5>Examples:</h5>
7853<pre>
7854 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7855 %sum = extractvalue {i32, i1} %res, 0
7856 %obit = extractvalue {i32, i1} %res, 1
7857 br i1 %obit, label %overflow, label %normal
7858</pre>
7859
7860</div>
7861
7862<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7863<h4>
7864 <a name="int_uadd_overflow">
7865 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7866 </a>
7867</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7868
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7869<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7870
7871<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7872<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7873 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7874
7875<pre>
7876 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7877 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7878 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7879</pre>
7880
7881<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7882<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7883 an unsigned addition of the two arguments, and indicate whether a carry
7884 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7885
7886<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7887<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7888 be of integer types of any bit width, but they must have the same bit
7889 width. The second element of the result structure must be of
7890 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7891 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7892
7893<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7894<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7895 an unsigned addition of the two arguments. They return a structure &mdash;
7896 the first element of which is the sum, and the second element of which is a
7897 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7898
7899<h5>Examples:</h5>
7900<pre>
7901 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7902 %sum = extractvalue {i32, i1} %res, 0
7903 %obit = extractvalue {i32, i1} %res, 1
7904 br i1 %obit, label %carry, label %normal
7905</pre>
7906
7907</div>
7908
7909<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7910<h4>
7911 <a name="int_ssub_overflow">
7912 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7913 </a>
7914</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7915
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7916<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7917
7918<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7919<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7920 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7921
7922<pre>
7923 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7924 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7925 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7926</pre>
7927
7928<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7929<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7930 a signed subtraction of the two arguments, and indicate whether an overflow
7931 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7932
7933<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7934<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7935 be of integer types of any bit width, but they must have the same bit
7936 width. The second element of the result structure must be of
7937 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7938 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7939
7940<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7941<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7942 a signed subtraction of the two arguments. They return a structure &mdash;
7943 the first element of which is the subtraction, and the second element of
7944 which is a bit specifying if the signed subtraction resulted in an
7945 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7946
7947<h5>Examples:</h5>
7948<pre>
7949 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7950 %sum = extractvalue {i32, i1} %res, 0
7951 %obit = extractvalue {i32, i1} %res, 1
7952 br i1 %obit, label %overflow, label %normal
7953</pre>
7954
7955</div>
7956
7957<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7958<h4>
7959 <a name="int_usub_overflow">
7960 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7961 </a>
7962</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7963
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7964<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7965
7966<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7967<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7968 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7969
7970<pre>
7971 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7972 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7973 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7974</pre>
7975
7976<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7977<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7978 an unsigned subtraction of the two arguments, and indicate whether an
7979 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7980
7981<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7982<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7983 be of integer types of any bit width, but they must have the same bit
7984 width. The second element of the result structure must be of
7985 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7986 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7987
7988<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7989<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7990 an unsigned subtraction of the two arguments. They return a structure &mdash;
7991 the first element of which is the subtraction, and the second element of
7992 which is a bit specifying if the unsigned subtraction resulted in an
7993 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7994
7995<h5>Examples:</h5>
7996<pre>
7997 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7998 %sum = extractvalue {i32, i1} %res, 0
7999 %obit = extractvalue {i32, i1} %res, 1
8000 br i1 %obit, label %overflow, label %normal
8001</pre>
8002
8003</div>
8004
8005<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8006<h4>
8007 <a name="int_smul_overflow">
8008 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
8009 </a>
8010</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8011
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8012<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8013
8014<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8015<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8016 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8017
8018<pre>
8019 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
8020 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
8021 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
8022</pre>
8023
8024<h5>Overview:</h5>
8025
8026<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8027 a signed multiplication of the two arguments, and indicate whether an
8028 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8029
8030<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8031<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8032 be of integer types of any bit width, but they must have the same bit
8033 width. The second element of the result structure must be of
8034 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
8035 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8036
8037<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8038<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8039 a signed multiplication of the two arguments. They return a structure &mdash;
8040 the first element of which is the multiplication, and the second element of
8041 which is a bit specifying if the signed multiplication resulted in an
8042 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]8043
8044<h5>Examples:</h5>
8045<pre>
8046 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
8047 %sum = extractvalue {i32, i1} %res, 0
8048 %obit = extractvalue {i32, i1} %res, 1
8049 br i1 %obit, label %overflow, label %normal
8050</pre>
8051
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]8052</div>
8053
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8054<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8055<h4>
8056 <a name="int_umul_overflow">
8057 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
8058 </a>
8059</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8060
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8061<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8062
8063<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8064<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8065 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8066
8067<pre>
8068 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
8069 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8070 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
8071</pre>
8072
8073<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8074<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8075 a unsigned multiplication of the two arguments, and indicate whether an
8076 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8077
8078<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8079<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8080 be of integer types of any bit width, but they must have the same bit
8081 width. The second element of the result structure must be of
8082 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
8083 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8084
8085<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8086<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8087 an unsigned multiplication of the two arguments. They return a structure
8088 &mdash; the first element of which is the multiplication, and the second
8089 element of which is a bit specifying if the unsigned multiplication resulted
8090 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8091
8092<h5>Examples:</h5>
8093<pre>
8094 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8095 %sum = extractvalue {i32, i1} %res, 0
8096 %obit = extractvalue {i32, i1} %res, 1
8097 br i1 %obit, label %overflow, label %normal
8098</pre>
8099
8100</div>
8101
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8102</div>
8103
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8104<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8105<h3>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]8106 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
8107</h3>
8108
8109<!-- _______________________________________________________________________ -->
8110
8111<h4>
8112 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
8113</h4>
8114
8115<div>
8116
8117<h5>Syntax:</h5>
8118<pre>
8119 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
8120 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
8121</pre>
8122
8123<h5>Overview:</h5>
8124<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
8125expressions that can be fused if the code generator determines that the fused
8126expression would be legal and efficient.</p>
8127
8128<h5>Arguments:</h5>
8129<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
8130multiplicands, a and b, and an addend c.</p>
8131
8132<h5>Semantics:</h5>
8133<p>The expression:</p>
8134<pre>
8135 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
8136</pre>
8137<p>is equivalent to the expression a * b + c, except that rounding will not be
8138performed between the multiplication and addition steps if the code generator
8139fuses the operations. Fusion is not guaranteed, even if the target platform
8140supports it. If a fused multiply-add is required the corresponding llvm.fma.*
8141intrinsic function should be used instead.</p>
8142
8143<h5>Examples:</h5>
8144<pre>
8145 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
8146</pre>
8147
8148</div>
8149
8150<!-- ======================================================================= -->
8151<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8152 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8153</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8154
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8155<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8156
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]8157<p>For most target platforms, half precision floating point is a storage-only
8158 format. This means that it is
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8159 a dense encoding (in memory) but does not support computation in the
8160 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8161
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8162<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8163 value as an i16, then convert it to float with <a
8164 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8165 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8166 double etc). To store the value back to memory, it is first converted to
8167 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8168 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8169 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8170
8171<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8172<h4>
8173 <a name="int_convert_to_fp16">
8174 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8175 </a>
8176</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8177
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8178<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8179
8180<h5>Syntax:</h5>
8181<pre>
8182 declare i16 @llvm.convert.to.fp16(f32 %a)
8183</pre>
8184
8185<h5>Overview:</h5>
8186<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8187 a conversion from single precision floating point format to half precision
8188 floating point format.</p>
8189
8190<h5>Arguments:</h5>
8191<p>The intrinsic function contains single argument - the value to be
8192 converted.</p>
8193
8194<h5>Semantics:</h5>
8195<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8196 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8197 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8198 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8199
8200<h5>Examples:</h5>
8201<pre>
8202 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8203 store i16 %res, i16* @x, align 2
8204</pre>
8205
8206</div>
8207
8208<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8209<h4>
8210 <a name="int_convert_from_fp16">
8211 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8212 </a>
8213</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8214
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8215<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8216
8217<h5>Syntax:</h5>
8218<pre>
8219 declare f32 @llvm.convert.from.fp16(i16 %a)
8220</pre>
8221
8222<h5>Overview:</h5>
8223<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8224 a conversion from half precision floating point format to single precision
8225 floating point format.</p>
8226
8227<h5>Arguments:</h5>
8228<p>The intrinsic function contains single argument - the value to be
8229 converted.</p>
8230
8231<h5>Semantics:</h5>
8232<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8233 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8234 precision floating point format. The input half-float value is represented by
8235 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8236
8237<h5>Examples:</h5>
8238<pre>
8239 %a = load i16* @x, align 2
8240 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8241</pre>
8242
8243</div>
8244
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8245</div>
8246
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8247<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8248<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8249 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8250</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8251
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8252<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8253
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8254<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8255 prefix), are described in
8256 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8257 Level Debugging</a> document.</p>
8258
8259</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8260
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8261<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8262<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8263 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8264</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8265
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8266<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8267
8268<p>The LLVM exception handling intrinsics (which all start with
8269 <tt>llvm.eh.</tt> prefix), are described in
8270 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8271 Handling</a> document.</p>
8272
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8273</div>
8274
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8275<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8276<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8277 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8278</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8279
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8280<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8281
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8282<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]8283 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8284 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8285 function pointer lacking the nest parameter - the caller does not need to
8286 provide a value for it. Instead, the value to use is stored in advance in a
8287 "trampoline", a block of memory usually allocated on the stack, which also
8288 contains code to splice the nest value into the argument list. This is used
8289 to implement the GCC nested function address extension.</p>
8290
8291<p>For example, if the function is
8292 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8293 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8294 follows:</p>
8295
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]8296<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8297 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8298 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8299 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8300 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8301 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8302</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8303
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8304<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8305 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8306
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8307<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8308<h4>
8309 <a name="int_it">
8310 '<tt>llvm.init.trampoline</tt>' Intrinsic
8311 </a>
8312</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8313
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8314<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8315
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8316<h5>Syntax:</h5>
8317<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8318 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8319</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8320
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8321<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8322<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8323 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8324
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8325<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8326<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8327 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8328 sufficiently aligned block of memory; this memory is written to by the
8329 intrinsic. Note that the size and the alignment are target-specific - LLVM
8330 currently provides no portable way of determining them, so a front-end that
8331 generates this intrinsic needs to have some target-specific knowledge.
8332 The <tt>func</tt> argument must hold a function bitcast to
8333 an <tt>i8*</tt>.</p>
8334
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8335<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8336<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8337 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8338 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8339 which can be <a href="#int_trampoline">bitcast (to a new function) and
8340 called</a>. The new function's signature is the same as that of
8341 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8342 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8343 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8344 with the same argument list, but with <tt>nval</tt> used for the missing
8345 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8346 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8347 to the returned function pointer is undefined.</p>
8348</div>
8349
8350<!-- _______________________________________________________________________ -->
8351<h4>
8352 <a name="int_at">
8353 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8354 </a>
8355</h4>
8356
8357<div>
8358
8359<h5>Syntax:</h5>
8360<pre>
8361 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8362</pre>
8363
8364<h5>Overview:</h5>
8365<p>This performs any required machine-specific adjustment to the address of a
8366 trampoline (passed as <tt>tramp</tt>).</p>
8367
8368<h5>Arguments:</h5>
8369<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8370 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8371 </a>.</p>
8372
8373<h5>Semantics:</h5>
8374<p>On some architectures the address of the code to be executed needs to be
8375 different to the address where the trampoline is actually stored. This
8376 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8377 after performing the required machine specific adjustments.
8378 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8379 executed</a>.
8380</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8381
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8382</div>
8383
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8384</div>
8385
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8386<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8387<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8388 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8389</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8390
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8391<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8392
8393<p>This class of intrinsics exists to information about the lifetime of memory
8394 objects and ranges where variables are immutable.</p>
8395
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8396<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8397<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8398 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8399</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8400
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8401<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8402
8403<h5>Syntax:</h5>
8404<pre>
8405 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8406</pre>
8407
8408<h5>Overview:</h5>
8409<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8410 object's lifetime.</p>
8411
8412<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8413<p>The first argument is a constant integer representing the size of the
8414 object, or -1 if it is variable sized. The second argument is a pointer to
8415 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8416
8417<h5>Semantics:</h5>
8418<p>This intrinsic indicates that before this point in the code, the value of the
8419 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]8420 never be used and has an undefined value. A load from the pointer that
8421 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8422 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8423
8424</div>
8425
8426<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8427<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8428 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8429</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8432
8433<h5>Syntax:</h5>
8434<pre>
8435 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8436</pre>
8437
8438<h5>Overview:</h5>
8439<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8440 object's lifetime.</p>
8441
8442<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8443<p>The first argument is a constant integer representing the size of the
8444 object, or -1 if it is variable sized. The second argument is a pointer to
8445 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8446
8447<h5>Semantics:</h5>
8448<p>This intrinsic indicates that after this point in the code, the value of the
8449 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8450 never be used and has an undefined value. Any stores into the memory object
8451 following this intrinsic may be removed as dead.
8452
8453</div>
8454
8455<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8456<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8457 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8458</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8459
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8460<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8461
8462<h5>Syntax:</h5>
8463<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8464 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8465</pre>
8466
8467<h5>Overview:</h5>
8468<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8469 a memory object will not change.</p>
8470
8471<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8472<p>The first argument is a constant integer representing the size of the
8473 object, or -1 if it is variable sized. The second argument is a pointer to
8474 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8475
8476<h5>Semantics:</h5>
8477<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8478 the return value, the referenced memory location is constant and
8479 unchanging.</p>
8480
8481</div>
8482
8483<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8484<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8485 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8486</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8487
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8488<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8489
8490<h5>Syntax:</h5>
8491<pre>
8492 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8493</pre>
8494
8495<h5>Overview:</h5>
8496<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8497 a memory object are mutable.</p>
8498
8499<h5>Arguments:</h5>
8500<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8501 The second argument is a constant integer representing the size of the
8502 object, or -1 if it is variable sized and the third argument is a pointer
8503 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8504
8505<h5>Semantics:</h5>
8506<p>This intrinsic indicates that the memory is mutable again.</p>
8507
8508</div>
8509
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8510</div>
8511
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8512<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8513<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8514 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8515</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8516
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8517<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8518
8519<p>This class of intrinsics is designed to be generic and has no specific
8520 purpose.</p>
8521
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8522<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8523<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8524 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8525</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8526
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8527<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8528
8529<h5>Syntax:</h5>
8530<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8531 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8532</pre>
8533
8534<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8535<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8536
8537<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8538<p>The first argument is a pointer to a value, the second is a pointer to a
8539 global string, the third is a pointer to a global string which is the source
8540 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8541
8542<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8543<p>This intrinsic allows annotation of local variables with arbitrary strings.
8544 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8545 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8546 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8547
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8548</div>
8549
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8550<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8551<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8552 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8553</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8554
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8555<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8556
8557<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8558<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8559 any integer bit width.</p>
8560
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8561<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8562 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8563 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8564 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8565 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8566 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8567</pre>
8568
8569<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8570<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8571
8572<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8573<p>The first argument is an integer value (result of some expression), the
8574 second is a pointer to a global string, the third is a pointer to a global
8575 string which is the source file name, and the last argument is the line
8576 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8577
8578<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8579<p>This intrinsic allows annotations to be put on arbitrary expressions with
8580 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8581 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8582 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8583
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8584</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8585
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8586<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8587<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8588 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8589</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8590
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8591<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8592
8593<h5>Syntax:</h5>
8594<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8595 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8596</pre>
8597
8598<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8599<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8600
8601<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8602<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8603
8604<h5>Semantics:</h5>
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8605<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8606 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8607 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8608
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8609</div>
8610
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8611<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8612<h4>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8613 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8614</h4>
8615
8616<div>
8617
8618<h5>Syntax:</h5>
8619<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8620 declare void @llvm.debugtrap() nounwind
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8621</pre>
8622
8623<h5>Overview:</h5>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8624<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8625
8626<h5>Arguments:</h5>
8627<p>None.</p>
8628
8629<h5>Semantics:</h5>
8630<p>This intrinsic is lowered to code which is intended to cause an execution
8631 trap with the intention of requesting the attention of a debugger.</p>
8632
8633</div>
8634
8635<!-- _______________________________________________________________________ -->
8636<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8637 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8638</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8639
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8640<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8641
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8642<h5>Syntax:</h5>
8643<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8644 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8645</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8646
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8647<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8648<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8649 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8650 ensure that it is placed on the stack before local variables.</p>
8651
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8652<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8653<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8654 arguments. The first argument is the value loaded from the stack
8655 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8656 that has enough space to hold the value of the guard.</p>
8657
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8658<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8659<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8660 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8661 stack. This is to ensure that if a local variable on the stack is
8662 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8663 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8664 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8665 function.</p>
8666
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8667</div>
8668
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8669<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8670<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8671 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8672</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8673
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8674<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8675
8676<h5>Syntax:</h5>
8677<pre>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8678 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8679 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8680</pre>
8681
8682<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8683<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8684 the optimizers to determine at compile time whether a) an operation (like
8685 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8686 runtime check for overflow isn't necessary. An object in this context means
8687 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8688
8689<h5>Arguments:</h5>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8690<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8691 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8692 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8693 true) or -1 (if false) when the object size is unknown.
8694 The second argument only accepts constants.</p>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8695
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8696<h5>Semantics:</h5>
Nuno Lopes01547b32012-05-09 15:52:43 +0000[diff] [blame]8697<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8698 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8699 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8700 (depending on the <tt>min</tt> argument).</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8701
8702</div>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8703<!-- _______________________________________________________________________ -->
8704<h4>
8705 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8706</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8707
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8708<div>
8709
8710<h5>Syntax:</h5>
8711<pre>
8712 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8713 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8714</pre>
8715
8716<h5>Overview:</h5>
8717<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8718 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8719
8720<h5>Arguments:</h5>
8721<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8722 argument is a value. The second argument is an expected value, this needs to
8723 be a constant value, variables are not allowed.</p>
8724
8725<h5>Semantics:</h5>
8726<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8727</div>
8728
Nuno Lopes4d6c8322012-07-05 17:37:07 +0000[diff] [blame]8729<!-- _______________________________________________________________________ -->
8730<h4>
8731 <a name="int_donothing">'<tt>llvm.donothing</tt>' Intrinsic</a>
8732</h4>
8733
8734<div>
8735
8736<h5>Syntax:</h5>
8737<pre>
8738 declare void @llvm.donothing() nounwind readnone
8739</pre>
8740
8741<h5>Overview:</h5>
8742<p>The <tt>llvm.donothing</tt> intrinsic doesn't perform any operation. It's the
8743only intrinsic that can be called with an invoke instruction.</p>
8744
8745<h5>Arguments:</h5>
8746<p>None.</p>
8747
8748<h5>Semantics:</h5>
8749<p>This intrinsic does nothing, and it's removed by optimizers and ignored by
8750codegen.</p>
8751</div>
8752
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8753</div>
8754
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8755</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8756<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8757<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8758<address>
8759 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8760 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8761 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8762 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8763
8764 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8765 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8766 Last modified: $Date$
8767</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8768
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8769</body>
8770</html>