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gerrit-public.fairphone.software / toolchain / llvm-project / 2165cf6e36e6017ce429ddd38a84aa5608c9658a / . / 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">
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Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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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 Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</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>
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]106 <li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]107 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]108 </ol>
109 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]110 </ol>
111 </li>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]112 <li><a href="#module_flags">Module Flags Metadata</a>
113 <ol>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]114 <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]115 </ol>
116 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]117 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
118 <ol>
119 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]120 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
121 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]122 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
123 Global Variable</a></li>
124 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
125 Global Variable</a></li>
126 </ol>
127 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#instref">Instruction Reference</a>
129 <ol>
130 <li><a href="#terminators">Terminator Instructions</a>
131 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
133 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]135 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]136 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]137 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]138 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]139 </ol>
140 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]141 <li><a href="#binaryops">Binary Operations</a>
142 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]148 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]149 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
150 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
151 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]152 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
153 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
154 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]157 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
158 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]159 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
160 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
161 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]163 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]164 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]167 <li><a href="#vectorops">Vector Operations</a>
168 <ol>
169 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
170 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
171 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]172 </ol>
173 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]174 <li><a href="#aggregateops">Aggregate Operations</a>
175 <ol>
176 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
177 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
178 </ol>
179 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]180 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]181 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]182 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
183 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
184 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
185 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
186 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
187 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]188 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]189 </ol>
190 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]191 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]192 <ol>
193 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
194 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
195 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
196 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]198 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
199 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
200 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
201 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]202 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
203 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]204 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]205 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]206 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]207 <li><a href="#otherops">Other Operations</a>
208 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]209 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
210 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]212 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]213 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]214 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]215 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]218 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]219 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]220 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]221 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
223 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
225 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
226 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]227 </ol>
228 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
230 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]231 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
232 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
233 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]236 <li><a href="#int_codegen">Code Generator Intrinsics</a>
237 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]238 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
239 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
240 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
241 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
242 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
243 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]244 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]245 </ol>
246 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]247 <li><a href="#int_libc">Standard C Library Intrinsics</a>
248 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]249 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]254 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
255 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]257 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
258 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]259 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Peter Collingbourne2165cf62012-07-03 12:25:40 +0000[diff] [blame^]260 <li><a href="#int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]261 </ol>
262 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]263 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]264 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]265 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]266 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
267 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
268 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]269 </ol>
270 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]271 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
272 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]273 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
275 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
276 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
277 <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]278 <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]279 </ol>
280 </li>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]281 <li><a href="#spec_arithmetic">Specialised Arithmetic Intrinsics</a>
282 <ol>
283 <li><a href="#fmuladd">'<tt>llvm.fmuladd</tt> Intrinsic</a></li>
284 </ol>
285 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]286 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
287 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]288 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
289 <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]290 </ol>
291 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]292 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]293 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]294 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]295 <ol>
296 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]297 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]298 </ol>
299 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]300 <li><a href="#int_memorymarkers">Memory Use Markers</a>
301 <ol>
Jakub Staszak5fd147f2011-12-04 20:44:25 +0000[diff] [blame]302 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
303 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
304 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
305 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]306 </ol>
307 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]308 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]309 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]310 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]311 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]312 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]313 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]314 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]315 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]316 <li><a href="#int_debugtrap">
317 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]318 <li><a href="#int_stackprotector">
319 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]320 <li><a href="#int_objectsize">
321 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]322 <li><a href="#int_expect">
323 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]324 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]325 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]326 </ol>
327 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]328</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]329
330<div class="doc_author">
331 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
332 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]336<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]338
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]339<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]340
341<p>This document is a reference manual for the LLVM assembly language. LLVM is
342 a Static Single Assignment (SSA) based representation that provides type
343 safety, low-level operations, flexibility, and the capability of representing
344 'all' high-level languages cleanly. It is the common code representation
345 used throughout all phases of the LLVM compilation strategy.</p>
346
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]348
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]349<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]350<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]351<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]352
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]353<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]354
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]355<p>The LLVM code representation is designed to be used in three different forms:
356 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
357 for fast loading by a Just-In-Time compiler), and as a human readable
358 assembly language representation. This allows LLVM to provide a powerful
359 intermediate representation for efficient compiler transformations and
360 analysis, while providing a natural means to debug and visualize the
361 transformations. The three different forms of LLVM are all equivalent. This
362 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]364<p>The LLVM representation aims to be light-weight and low-level while being
365 expressive, typed, and extensible at the same time. It aims to be a
366 "universal IR" of sorts, by being at a low enough level that high-level ideas
367 may be cleanly mapped to it (similar to how microprocessors are "universal
368 IR's", allowing many source languages to be mapped to them). By providing
369 type information, LLVM can be used as the target of optimizations: for
370 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]371 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]372 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]374<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]375<h4>
376 <a name="wellformed">Well-Formedness</a>
377</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]379<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]380
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]381<p>It is important to note that this document describes 'well formed' LLVM
382 assembly language. There is a difference between what the parser accepts and
383 what is considered 'well formed'. For example, the following instruction is
384 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]385
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]386<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]387%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388</pre>
389
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]390<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
391 LLVM infrastructure provides a verification pass that may be used to verify
392 that an LLVM module is well formed. This pass is automatically run by the
393 parser after parsing input assembly and by the optimizer before it outputs
394 bitcode. The violations pointed out by the verifier pass indicate bugs in
395 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]396
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]397</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]398
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]399</div>
400
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]401<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]402
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]403<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]404<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]405<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]406
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]407<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]408
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]409<p>LLVM identifiers come in two basic types: global and local. Global
410 identifiers (functions, global variables) begin with the <tt>'@'</tt>
411 character. Local identifiers (register names, types) begin with
412 the <tt>'%'</tt> character. Additionally, there are three different formats
413 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]414
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]415<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]416 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]417 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
418 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
419 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
420 other characters in their names can be surrounded with quotes. Special
421 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
422 ASCII code for the character in hexadecimal. In this way, any character
423 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]425 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]426 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]427
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]428 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]429 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]430</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]431
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]432<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]433 don't need to worry about name clashes with reserved words, and the set of
434 reserved words may be expanded in the future without penalty. Additionally,
435 unnamed identifiers allow a compiler to quickly come up with a temporary
436 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]438<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]439 languages. There are keywords for different opcodes
440 ('<tt><a href="#i_add">add</a></tt>',
441 '<tt><a href="#i_bitcast">bitcast</a></tt>',
442 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
443 ('<tt><a href="#t_void">void</a></tt>',
444 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
445 reserved words cannot conflict with variable names, because none of them
446 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447
448<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]449 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]451<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]453<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]457<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]459<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]460%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
462
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]463<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]464
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]465<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]466%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
467%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]468%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469</pre>
470
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
472 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]474<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]475 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]476 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
478 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]479 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]481 <li>Unnamed temporaries are numbered sequentially</li>
482</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]483
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]484<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]485 demonstrating instructions, we will follow an instruction with a comment that
486 defines the type and name of value produced. Comments are shown in italic
487 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]488
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]489</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]490
491<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]492<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]494<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]495<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]496<h3>
497 <a name="modulestructure">Module Structure</a>
498</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]500<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]501
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]502<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
503 translation unit of the input programs. Each module consists of functions,
504 global variables, and symbol table entries. Modules may be combined together
505 with the LLVM linker, which merges function (and global variable)
506 definitions, resolves forward declarations, and merges symbol table
507 entries. Here is an example of the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]508
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]509<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]510<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]511<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]512
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]513<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]514<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]515
516<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]517define i32 @main() { <i>; i32()* </i>&nbsp;
518 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]519 %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]520
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]521 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]522 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]523 <a href="#i_ret">ret</a> i32 0&nbsp;
524}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]525
526<i>; Named metadata</i>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]527!1 = metadata !{i32 42}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]528!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]529</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]530
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]531<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]532 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]533 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]534 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]535 "<tt>foo</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]536
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]537<p>In general, a module is made up of a list of global values (where both
538 functions and global variables are global values). Global values are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]539 represented by a pointer to a memory location (in this case, a pointer to an
540 array of char, and a pointer to a function), and have one of the
541 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]542
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]543</div>
544
545<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]546<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]547 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]548</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]549
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]550<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]551
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]552<p>All Global Variables and Functions have one of the following types of
553 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]554
555<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]557 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
558 by objects in the current module. In particular, linking code into a
559 module with an private global value may cause the private to be renamed as
560 necessary to avoid collisions. Because the symbol is private to the
561 module, all references can be updated. This doesn't show up in any symbol
562 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]563
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]565 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
566 assembler and evaluated by the linker. Unlike normal strong symbols, they
567 are removed by the linker from the final linked image (executable or
568 dynamic library).</dd>
569
570 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
571 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
572 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
573 linker. The symbols are removed by the linker from the final linked image
574 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]575
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]576 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
577 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
578 of the object is not taken. For instance, functions that had an inline
579 definition, but the compiler decided not to inline it. Note,
580 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
581 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
582 visibility. The symbols are removed by the linker from the final linked
583 image (executable or dynamic library).</dd>
584
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]586 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]587 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
588 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]589
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]591 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]592 into the object file corresponding to the LLVM module. They exist to
593 allow inlining and other optimizations to take place given knowledge of
594 the definition of the global, which is known to be somewhere outside the
595 module. Globals with <tt>available_externally</tt> linkage are allowed to
596 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
597 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]598
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]600 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]601 the same name when linkage occurs. This can be used to implement
602 some forms of inline functions, templates, or other code which must be
603 generated in each translation unit that uses it, but where the body may
604 be overridden with a more definitive definition later. Unreferenced
605 <tt>linkonce</tt> globals are allowed to be discarded. Note that
606 <tt>linkonce</tt> linkage does not actually allow the optimizer to
607 inline the body of this function into callers because it doesn't know if
608 this definition of the function is the definitive definition within the
609 program or whether it will be overridden by a stronger definition.
610 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
611 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]612
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
615 <tt>linkonce</tt> linkage, except that unreferenced globals with
616 <tt>weak</tt> linkage may not be discarded. This is used for globals that
617 are declared "weak" in C source code.</dd>
618
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]619 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]620 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
621 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
622 global scope.
623 Symbols with "<tt>common</tt>" linkage are merged in the same way as
624 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]625 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]626 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]627 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
628 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]629
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]630
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]631 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]632 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]633 pointer to array type. When two global variables with appending linkage
634 are linked together, the two global arrays are appended together. This is
635 the LLVM, typesafe, equivalent of having the system linker append together
636 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]637
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]639 <dd>The semantics of this linkage follow the ELF object file model: the symbol
640 is weak until linked, if not linked, the symbol becomes null instead of
641 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]642
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
644 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]645 <dd>Some languages allow differing globals to be merged, such as two functions
646 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]647 that only equivalent globals are ever merged (the "one definition rule"
648 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]649 and <tt>weak_odr</tt> linkage types to indicate that the global will only
650 be merged with equivalent globals. These linkage types are otherwise the
651 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]652
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]653 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]654 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]655 visible, meaning that it participates in linkage and can be used to
656 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]657</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]658
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]659<p>The next two types of linkage are targeted for Microsoft Windows platform
660 only. They are designed to support importing (exporting) symbols from (to)
661 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]664 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]665 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]666 or variable via a global pointer to a pointer that is set up by the DLL
667 exporting the symbol. On Microsoft Windows targets, the pointer name is
668 formed by combining <code>__imp_</code> and the function or variable
669 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]670
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]671 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]672 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]673 pointer to a pointer in a DLL, so that it can be referenced with the
674 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
675 name is formed by combining <code>__imp_</code> and the function or
676 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</dl>
678
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]679<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
680 another module defined a "<tt>.LC0</tt>" variable and was linked with this
681 one, one of the two would be renamed, preventing a collision. Since
682 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
683 declarations), they are accessible outside of the current module.</p>
684
685<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]686 other than <tt>external</tt>, <tt>dllimport</tt>
687 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]688
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]689<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]690 or <tt>weak_odr</tt> linkages.</p>
691
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]692</div>
693
694<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]695<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]696 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]697</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]698
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]699<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]702 and <a href="#i_invoke">invokes</a> can all have an optional calling
703 convention specified for the call. The calling convention of any pair of
704 dynamic caller/callee must match, or the behavior of the program is
705 undefined. The following calling conventions are supported by LLVM, and more
706 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]710 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]711 specified) matches the target C calling conventions. This calling
712 convention supports varargs function calls and tolerates some mismatch in
713 the declared prototype and implemented declaration of the function (as
714 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]715
716 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]717 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]718 (e.g. by passing things in registers). This calling convention allows the
719 target to use whatever tricks it wants to produce fast code for the
720 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]721 (Application Binary Interface).
722 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]723 when this or the GHC convention is used.</a> This calling convention
724 does not support varargs and requires the prototype of all callees to
725 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]726
727 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]728 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]729 as possible under the assumption that the call is not commonly executed.
730 As such, these calls often preserve all registers so that the call does
731 not break any live ranges in the caller side. This calling convention
732 does not support varargs and requires the prototype of all callees to
733 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]734
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]735 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
736 <dd>This calling convention has been implemented specifically for use by the
737 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
738 It passes everything in registers, going to extremes to achieve this by
739 disabling callee save registers. This calling convention should not be
740 used lightly but only for specific situations such as an alternative to
741 the <em>register pinning</em> performance technique often used when
742 implementing functional programming languages.At the moment only X86
743 supports this convention and it has the following limitations:
744 <ul>
745 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
746 floating point types are supported.</li>
747 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
748 6 floating point parameters.</li>
749 </ul>
750 This calling convention supports
751 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
752 requires both the caller and callee are using it.
753 </dd>
754
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]755 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]756 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]757 target-specific calling conventions to be used. Target specific calling
758 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]759</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]760
761<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]762 support Pascal conventions or any other well-known target-independent
763 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]764
765</div>
766
767<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]768<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]770</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]772<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]773
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]774<p>All Global Variables and Functions have one of the following visibility
775 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
777<dl>
778 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]779 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]780 that the declaration is visible to other modules and, in shared libraries,
781 means that the declared entity may be overridden. On Darwin, default
782 visibility means that the declaration is visible to other modules. Default
783 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]784
785 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]786 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]787 object if they are in the same shared object. Usually, hidden visibility
788 indicates that the symbol will not be placed into the dynamic symbol
789 table, so no other module (executable or shared library) can reference it
790 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]791
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]792 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]793 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 the dynamic symbol table, but that references within the defining module
795 will bind to the local symbol. That is, the symbol cannot be overridden by
796 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]797</dl>
798
799</div>
800
801<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]802<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]803 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]804</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]805
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]806<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]807
808<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]809 it easier to read the IR and make the IR more condensed (particularly when
810 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]811
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]812<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]813%mytype = type { %mytype*, i32 }
814</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]816<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]817 "<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]818 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]819
820<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]821 and that you can therefore specify multiple names for the same type. This
822 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
823 uses structural typing, the name is not part of the type. When printing out
824 LLVM IR, the printer will pick <em>one name</em> to render all types of a
825 particular shape. This means that if you have code where two different
826 source types end up having the same LLVM type, that the dumper will sometimes
827 print the "wrong" or unexpected type. This is an important design point and
828 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]829
830</div>
831
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]832<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]833<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]834 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]835</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]837<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]838
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]839<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]840 instead of run-time. Global variables may optionally be initialized, may
841 have an explicit section to be placed in, and may have an optional explicit
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]842 alignment specified.</p>
843
844<p>A variable may be defined as <tt>thread_local</tt>, which
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]845 means that it will not be shared by threads (each thread will have a
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]846 separated copy of the variable). Not all targets support thread-local
847 variables. Optionally, a TLS model may be specified:</p>
848
849<dl>
850 <dt><b><tt>localdynamic</tt></b>:</dt>
851 <dd>For variables that are only used within the current shared library.</dd>
852
853 <dt><b><tt>initialexec</tt></b>:</dt>
854 <dd>For variables in modules that will not be loaded dynamically.</dd>
855
856 <dt><b><tt>localexec</tt></b>:</dt>
857 <dd>For variables defined in the executable and only used within it.</dd>
858</dl>
859
860<p>The models correspond to the ELF TLS models; see
861 <a href="http://people.redhat.com/drepper/tls.pdf">ELF
862 Handling For Thread-Local Storage</a> for more information on under which
863 circumstances the different models may be used. The target may choose a
864 different TLS model if the specified model is not supported, or if a better
865 choice of model can be made.</p>
866
867<p>A variable may be defined as a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868 "constant," which indicates that the contents of the variable
869 will <b>never</b> be modified (enabling better optimization, allowing the
870 global data to be placed in the read-only section of an executable, etc).
871 Note that variables that need runtime initialization cannot be marked
872 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]874<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
875 constant, even if the final definition of the global is not. This capability
876 can be used to enable slightly better optimization of the program, but
877 requires the language definition to guarantee that optimizations based on the
878 'constantness' are valid for the translation units that do not include the
879 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]880
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]881<p>As SSA values, global variables define pointer values that are in scope
882 (i.e. they dominate) all basic blocks in the program. Global variables
883 always define a pointer to their "content" type because they describe a
884 region of memory, and all memory objects in LLVM are accessed through
885 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]886
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]887<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
888 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]889 like this can be merged with other constants if they have the same
890 initializer. Note that a constant with significant address <em>can</em>
891 be merged with a <tt>unnamed_addr</tt> constant, the result being a
892 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]894<p>A global variable may be declared to reside in a target-specific numbered
895 address space. For targets that support them, address spaces may affect how
896 optimizations are performed and/or what target instructions are used to
897 access the variable. The default address space is zero. The address space
898 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]899
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]900<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]901 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]902
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]903<p>An explicit alignment may be specified for a global, which must be a power
904 of 2. If not present, or if the alignment is set to zero, the alignment of
905 the global is set by the target to whatever it feels convenient. If an
906 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]907 alignment. Targets and optimizers are not allowed to over-align the global
908 if the global has an assigned section. In this case, the extra alignment
909 could be observable: for example, code could assume that the globals are
910 densely packed in their section and try to iterate over them as an array,
911 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]912
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]913<p>For example, the following defines a global in a numbered address space with
914 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]915
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]916<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]917@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]918</pre>
919
Hans Wennborgcbe34b42012-06-23 11:37:03 +0000[diff] [blame]920<p>The following example defines a thread-local global with
921 the <tt>initialexec</tt> TLS model:</p>
922
923<pre class="doc_code">
924@G = thread_local(initialexec) global i32 0, align 4
925</pre>
926
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]927</div>
928
929
930<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]931<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]932 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]933</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]935<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]936
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]937<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]938 optional <a href="#linkage">linkage type</a>, an optional
939 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]940 <a href="#callingconv">calling convention</a>,
941 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942 <a href="#paramattrs">parameter attribute</a> for the return type, a function
943 name, a (possibly empty) argument list (each with optional
944 <a href="#paramattrs">parameter attributes</a>), optional
945 <a href="#fnattrs">function attributes</a>, an optional section, an optional
946 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
947 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]948
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]949<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
950 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]951 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]952 <a href="#callingconv">calling convention</a>,
953 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954 <a href="#paramattrs">parameter attribute</a> for the return type, a function
955 name, a possibly empty list of arguments, an optional alignment, and an
956 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]957
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]958<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]959 (Control Flow Graph) for the function. Each basic block may optionally start
960 with a label (giving the basic block a symbol table entry), contains a list
961 of instructions, and ends with a <a href="#terminators">terminator</a>
962 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]963
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]964<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]965 executed on entrance to the function, and it is not allowed to have
966 predecessor basic blocks (i.e. there can not be any branches to the entry
967 block of a function). Because the block can have no predecessors, it also
968 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]969
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]970<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]971 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]972
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]973<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]974 the alignment is set to zero, the alignment of the function is set by the
975 target to whatever it feels convenient. If an explicit alignment is
976 specified, the function is forced to have at least that much alignment. All
977 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]978
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]979<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]980 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]981
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]982<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]983<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]984define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]985 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
986 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
987 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
988 [<a href="#gc">gc</a>] { ... }
989</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]990
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]991</div>
992
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]993<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]994<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]995 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]996</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]997
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]998<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]999
1000<p>Aliases act as "second name" for the aliasee value (which can be either
1001 function, global variable, another alias or bitcast of global value). Aliases
1002 may have an optional <a href="#linkage">linkage type</a>, and an
1003 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]1004
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1005<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]1007@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]1008</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]1009
1010</div>
1011
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1012<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1013<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1014 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1015</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1016
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1017<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1018
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]1019<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1020 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]1021 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1022
1023<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1024<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1025; Some unnamed metadata nodes, which are referenced by the named metadata.
1026!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1027!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1028!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]1029; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]1030!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1031</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1032
1033</div>
1034
1035<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1036<h3>
1037 <a name="paramattrs">Parameter Attributes</a>
1038</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1039
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1040<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041
1042<p>The return type and each parameter of a function type may have a set of
1043 <i>parameter attributes</i> associated with them. Parameter attributes are
1044 used to communicate additional information about the result or parameters of
1045 a function. Parameter attributes are considered to be part of the function,
1046 not of the function type, so functions with different parameter attributes
1047 can have the same function type.</p>
1048
1049<p>Parameter attributes are simple keywords that follow the type specified. If
1050 multiple parameter attributes are needed, they are space separated. For
1051 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1052
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1053<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1054declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1055declare i32 @atoi(i8 zeroext)
1056declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1057</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1058
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1060 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1061
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1062<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1063
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1064<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1067 should be zero-extended to the extent required by the target's ABI (which
1068 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1069 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1070
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1071 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1072 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1073 should be sign-extended to the extent required by the target's ABI (which
1074 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1075 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1076
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1077 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1078 <dd>This indicates that this parameter or return value should be treated in a
1079 special target-dependent fashion during while emitting code for a function
1080 call or return (usually, by putting it in a register as opposed to memory,
1081 though some targets use it to distinguish between two different kinds of
1082 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1083
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1084 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1085 <dd><p>This indicates that the pointer parameter should really be passed by
1086 value to the function. The attribute implies that a hidden copy of the
1087 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088 is made between the caller and the callee, so the callee is unable to
Chris Lattner747482c2012-05-30 00:40:23 +0000[diff] [blame]1089 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1090 pointer arguments. It is generally used to pass structs and arrays by
1091 value, but is also valid on pointers to scalars. The copy is considered
1092 to belong to the caller not the callee (for example,
1093 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1094 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1095 values.</p>
1096
1097 <p>The byval attribute also supports specifying an alignment with
1098 the align attribute. It indicates the alignment of the stack slot to
1099 form and the known alignment of the pointer specified to the call site. If
1100 the alignment is not specified, then the code generator makes a
1101 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1102
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1103 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This indicates that the pointer parameter specifies the address of a
1105 structure that is the return value of the function in the source program.
1106 This pointer must be guaranteed by the caller to be valid: loads and
1107 stores to the structure may be assumed by the callee to not to trap. This
1108 may only be applied to the first parameter. This is not a valid attribute
1109 for return values. </dd>
1110
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1111 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1112 <dd>This indicates that pointer values
1113 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1114 value do not alias pointer values which are not <i>based</i> on it,
1115 ignoring certain "irrelevant" dependencies.
1116 For a call to the parent function, dependencies between memory
1117 references from before or after the call and from those during the call
1118 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1119 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1120 The caller shares the responsibility with the callee for ensuring that
1121 these requirements are met.
1122 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1123 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1124<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1125 Note that this definition of <tt>noalias</tt> is intentionally
1126 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1127 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1128<br>
1129 For function return values, C99's <tt>restrict</tt> is not meaningful,
1130 while LLVM's <tt>noalias</tt> is.
1131 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1132
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1133 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This indicates that the callee does not make any copies of the pointer
1135 that outlive the callee itself. This is not a valid attribute for return
1136 values.</dd>
1137
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1138 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This indicates that the pointer parameter can be excised using the
1140 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1141 attribute for return values.</dd>
1142</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1143
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1144</div>
1145
1146<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1147<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1148 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1149</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1150
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1151<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1152
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1153<p>Each function may specify a garbage collector name, which is simply a
1154 string:</p>
1155
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1156<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1157define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1158</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1159
1160<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161 collector which will cause the compiler to alter its output in order to
1162 support the named garbage collection algorithm.</p>
1163
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1164</div>
1165
1166<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1167<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1168 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1169</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1170
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1171<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1172
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1173<p>Function attributes are set to communicate additional information about a
1174 function. Function attributes are considered to be part of the function, not
1175 of the function type, so functions with different parameter attributes can
1176 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1177
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1178<p>Function attributes are simple keywords that follow the type specified. If
1179 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1180
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1181<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1182define void @f() noinline { ... }
1183define void @f() alwaysinline { ... }
1184define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1185define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1186</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1187
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1188<dl>
Kostya Serebryanya5054ad2012-01-20 17:56:17 +0000[diff] [blame]1189 <dt><tt><b>address_safety</b></tt></dt>
1190 <dd>This attribute indicates that the address safety analysis
1191 is enabled for this function. </dd>
1192
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1193 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1194 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1195 the backend should forcibly align the stack pointer. Specify the
1196 desired alignment, which must be a power of two, in parentheses.
1197
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1198 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1199 <dd>This attribute indicates that the inliner should attempt to inline this
1200 function into callers whenever possible, ignoring any active inlining size
1201 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1202
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1203 <dt><tt><b>nonlazybind</b></tt></dt>
1204 <dd>This attribute suppresses lazy symbol binding for the function. This
1205 may make calls to the function faster, at the cost of extra program
1206 startup time if the function is not called during program startup.</dd>
1207
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1208 <dt><tt><b>inlinehint</b></tt></dt>
1209 <dd>This attribute indicates that the source code contained a hint that inlining
1210 this function is desirable (such as the "inline" keyword in C/C++). It
1211 is just a hint; it imposes no requirements on the inliner.</dd>
1212
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1213 <dt><tt><b>naked</b></tt></dt>
1214 <dd>This attribute disables prologue / epilogue emission for the function.
1215 This can have very system-specific consequences.</dd>
1216
1217 <dt><tt><b>noimplicitfloat</b></tt></dt>
1218 <dd>This attributes disables implicit floating point instructions.</dd>
1219
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1220 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1221 <dd>This attribute indicates that the inliner should never inline this
1222 function in any situation. This attribute may not be used together with
1223 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1224
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1225 <dt><tt><b>noredzone</b></tt></dt>
1226 <dd>This attribute indicates that the code generator should not use a red
1227 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1228
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This function attribute indicates that the function never returns
1231 normally. This produces undefined behavior at runtime if the function
1232 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1233
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1234 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1235 <dd>This function attribute indicates that the function never returns with an
1236 unwind or exceptional control flow. If the function does unwind, its
1237 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1238
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1239 <dt><tt><b>optsize</b></tt></dt>
1240 <dd>This attribute suggests that optimization passes and code generator passes
1241 make choices that keep the code size of this function low, and otherwise
1242 do optimizations specifically to reduce code size.</dd>
1243
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1244 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1245 <dd>This attribute indicates that the function computes its result (or decides
1246 to unwind an exception) based strictly on its arguments, without
1247 dereferencing any pointer arguments or otherwise accessing any mutable
1248 state (e.g. memory, control registers, etc) visible to caller functions.
1249 It does not write through any pointer arguments
1250 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1251 changes any state visible to callers. This means that it cannot unwind
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1252 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1253
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1254 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1255 <dd>This attribute indicates that the function does not write through any
1256 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1257 arguments) or otherwise modify any state (e.g. memory, control registers,
1258 etc) visible to caller functions. It may dereference pointer arguments
1259 and read state that may be set in the caller. A readonly function always
1260 returns the same value (or unwinds an exception identically) when called
1261 with the same set of arguments and global state. It cannot unwind an
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1262 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1263
Bill Wendlingb437ab82011-12-05 21:27:54 +0000[diff] [blame]1264 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1265 <dd>This attribute indicates that this function can return twice. The
1266 C <code>setjmp</code> is an example of such a function. The compiler
1267 disables some optimizations (like tail calls) in the caller of these
1268 functions.</dd>
1269
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1270 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1271 <dd>This attribute indicates that the function should emit a stack smashing
1272 protector. It is in the form of a "canary"&mdash;a random value placed on
1273 the stack before the local variables that's checked upon return from the
1274 function to see if it has been overwritten. A heuristic is used to
1275 determine if a function needs stack protectors or not.<br>
1276<br>
1277 If a function that has an <tt>ssp</tt> attribute is inlined into a
1278 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1279 function will have an <tt>ssp</tt> attribute.</dd>
1280
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1281 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282 <dd>This attribute indicates that the function should <em>always</em> emit a
1283 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1284 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1285<br>
1286 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1287 function that doesn't have an <tt>sspreq</tt> attribute or which has
1288 an <tt>ssp</tt> attribute, then the resulting function will have
1289 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1290
1291 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1292 <dd>This attribute indicates that the ABI being targeted requires that
1293 an unwind table entry be produce for this function even if we can
1294 show that no exceptions passes by it. This is normally the case for
1295 the ELF x86-64 abi, but it can be disabled for some compilation
1296 units.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1297</dl>
1298
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1299</div>
1300
1301<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1302<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1303 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1304</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1305
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1306<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307
1308<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1309 the GCC "file scope inline asm" blocks. These blocks are internally
1310 concatenated by LLVM and treated as a single unit, but may be separated in
1311 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1312
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1313<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1314module asm "inline asm code goes here"
1315module asm "more can go here"
1316</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1317
1318<p>The strings can contain any character by escaping non-printable characters.
1319 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]1320 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1321
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1322<p>The inline asm code is simply printed to the machine code .s file when
1323 assembly code is generated.</p>
1324
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1325</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1326
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1327<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1328<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1329 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1330</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1331
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1332<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1335 data is to be laid out in memory. The syntax for the data layout is
1336 simply:</p>
1337
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1338<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1339target datalayout = "<i>layout specification</i>"
1340</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The <i>layout specification</i> consists of a list of specifications
1343 separated by the minus sign character ('-'). Each specification starts with
1344 a letter and may include other information after the letter to define some
1345 aspect of the data layout. The specifications accepted are as follows:</p>
1346
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1347<dl>
1348 <dt><tt>E</tt></dt>
1349 <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]1350 bits with the most significance have the lowest address location.</dd>
1351
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1352 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1353 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1354 the bits with the least significance have the lowest address
1355 location.</dd>
1356
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1357 <dt><tt>S<i>size</i></tt></dt>
1358 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1359 of stack variables is limited to the natural stack alignment to avoid
1360 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1361 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1362 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1363
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1364 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1365 <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]1366 <i>preferred</i> alignments. All sizes are in bits. Specifying
1367 the <i>pref</i> alignment is optional. If omitted, the
1368 preceding <tt>:</tt> should be omitted too.</dd>
1369
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1370 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1371 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1372 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1373
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1374 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1375 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1376 <i>size</i>.</dd>
1377
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1378 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1379 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1380 <i>size</i>. Only values of <i>size</i> that are supported by the target
1381 will work. 32 (float) and 64 (double) are supported on all targets;
1382 80 or 128 (different flavors of long double) are also supported on some
1383 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1384
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1385 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1386 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1387 <i>size</i>.</dd>
1388
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1389 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1390 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1392
1393 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1394 <dd>This specifies a set of native integer widths for the target CPU
1395 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1396 "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]1397 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1398 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1399</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1400
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1401<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1402 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1403 specifications in the <tt>datalayout</tt> keyword. The default specifications
1404 are given in this list:</p>
1405
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1406<ul>
1407 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1408 <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]1409 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1410 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1411 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1412 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1413 <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]1414 alignment of 64-bits</li>
1415 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1416 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1417 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1418 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1419 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1420 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1421</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1422
1423<p>When LLVM is determining the alignment for a given type, it uses the
1424 following rules:</p>
1425
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1426<ol>
1427 <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]1428 specification is used.</li>
1429
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1430 <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]1431 smallest integer type that is larger than the bitwidth of the sought type
1432 is used. If none of the specifications are larger than the bitwidth then
1433 the the largest integer type is used. For example, given the default
1434 specifications above, the i7 type will use the alignment of i8 (next
1435 largest) while both i65 and i256 will use the alignment of i64 (largest
1436 specified).</li>
1437
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1438 <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]1439 largest vector type that is smaller than the sought vector type will be
1440 used as a fall back. This happens because &lt;128 x double&gt; can be
1441 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1442</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1444<p>The function of the data layout string may not be what you expect. Notably,
1445 this is not a specification from the frontend of what alignment the code
1446 generator should use.</p>
1447
1448<p>Instead, if specified, the target data layout is required to match what the
1449 ultimate <em>code generator</em> expects. This string is used by the
1450 mid-level optimizers to
1451 improve code, and this only works if it matches what the ultimate code
1452 generator uses. If you would like to generate IR that does not embed this
1453 target-specific detail into the IR, then you don't have to specify the
1454 string. This will disable some optimizations that require precise layout
1455 information, but this also prevents those optimizations from introducing
1456 target specificity into the IR.</p>
1457
1458
1459
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1460</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1461
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1462<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1463<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1464 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1465</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1466
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1467<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1468
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1469<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1470with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1471is undefined. Pointer values are associated with address ranges
1472according to the following rules:</p>
1473
1474<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1475 <li>A pointer value is associated with the addresses associated with
1476 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1477 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1478 range of the variable's storage.</li>
1479 <li>The result value of an allocation instruction is associated with
1480 the address range of the allocated storage.</li>
1481 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1482 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1483 <li>An integer constant other than zero or a pointer value returned
1484 from a function not defined within LLVM may be associated with address
1485 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1486 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1487 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1488</ul>
1489
1490<p>A pointer value is <i>based</i> on another pointer value according
1491 to the following rules:</p>
1492
1493<ul>
1494 <li>A pointer value formed from a
1495 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1496 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1497 <li>The result value of a
1498 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1499 of the <tt>bitcast</tt>.</li>
1500 <li>A pointer value formed by an
1501 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1502 pointer values that contribute (directly or indirectly) to the
1503 computation of the pointer's value.</li>
1504 <li>The "<i>based</i> on" relationship is transitive.</li>
1505</ul>
1506
1507<p>Note that this definition of <i>"based"</i> is intentionally
1508 similar to the definition of <i>"based"</i> in C99, though it is
1509 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1510
1511<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1512<tt><a href="#i_load">load</a></tt> merely indicates the size and
1513alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1514interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1515<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1516and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1517
1518<p>Consequently, type-based alias analysis, aka TBAA, aka
1519<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1520LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1521additional information which specialized optimization passes may use
1522to implement type-based alias analysis.</p>
1523
1524</div>
1525
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1526<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1527<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1528 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1529</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1530
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1531<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1532
1533<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1534href="#i_store"><tt>store</tt></a>s, and <a
1535href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1536The optimizers must not change the number of volatile operations or change their
1537order of execution relative to other volatile operations. The optimizers
1538<i>may</i> change the order of volatile operations relative to non-volatile
1539operations. This is not Java's "volatile" and has no cross-thread
1540synchronization behavior.</p>
1541
1542</div>
1543
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1544<!-- ======================================================================= -->
1545<h3>
1546 <a name="memmodel">Memory Model for Concurrent Operations</a>
1547</h3>
1548
1549<div>
1550
1551<p>The LLVM IR does not define any way to start parallel threads of execution
1552or to register signal handlers. Nonetheless, there are platform-specific
1553ways to create them, and we define LLVM IR's behavior in their presence. This
1554model is inspired by the C++0x memory model.</p>
1555
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1556<p>For a more informal introduction to this model, see the
1557<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1558
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1559<p>We define a <i>happens-before</i> partial order as the least partial order
1560that</p>
1561<ul>
1562 <li>Is a superset of single-thread program order, and</li>
1563 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1564 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1565 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1566 creation, thread joining, etc., and by atomic instructions.
1567 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1568 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1569</ul>
1570
1571<p>Note that program order does not introduce <i>happens-before</i> edges
1572between a thread and signals executing inside that thread.</p>
1573
1574<p>Every (defined) read operation (load instructions, memcpy, atomic
1575loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1576(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1577stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1578initialized globals are considered to have a write of the initializer which is
1579atomic and happens before any other read or write of the memory in question.
1580For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1581any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1582
1583<ul>
1584 <li>If <var>write<sub>1</sub></var> happens before
1585 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1586 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1587 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1588 <li>If <var>R<sub>byte</sub></var> happens before
1589 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1590 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1591</ul>
1592
1593<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1594<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1595 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1596 is supposed to give guarantees which can support
1597 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1598 addresses which do not behave like normal memory. It does not generally
1599 provide cross-thread synchronization.)
1600 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1601 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1602 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1603 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1604 <var>R<sub>byte</sub></var> returns the value written by that
1605 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1606 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1607 <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]1608 values written. See the <a href="#ordering">Atomic Memory Ordering
1609 Constraints</a> section for additional constraints on how the choice
1610 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1611 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1612</ul>
1613
1614<p><var>R</var> returns the value composed of the series of bytes it read.
1615This implies that some bytes within the value may be <tt>undef</tt>
1616<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1617defines the semantics of the operation; it doesn't mean that targets will
1618emit more than one instruction to read the series of bytes.</p>
1619
1620<p>Note that in cases where none of the atomic intrinsics are used, this model
1621places only one restriction on IR transformations on top of what is required
1622for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1623otherwise be stored is not allowed in general. (Specifically, in the case
1624where another thread might write to and read from an address, introducing a
1625store can change a load that may see exactly one write into a load that may
1626see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1627
1628<!-- FIXME: This model assumes all targets where concurrency is relevant have
1629a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1630none of the backends currently in the tree fall into this category; however,
1631there might be targets which care. If there are, we want a paragraph
1632like the following:
1633
1634Targets may specify that stores narrower than a certain width are not
1635available; on such a target, for the purposes of this model, treat any
1636non-atomic write with an alignment or width less than the minimum width
1637as if it writes to the relevant surrounding bytes.
1638-->
1639
1640</div>
1641
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1642<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1643<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1644 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1645</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1646
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1647<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1648
1649<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1650<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1651<a href="#i_fence"><code>fence</code></a>,
1652<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1653<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1654that determines which other atomic instructions on the same address they
1655<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1656but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1657check those specs (see spec references in the
Nick Lewycky75499f52012-01-23 08:47:21 +0000[diff] [blame]1658<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1659<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1660treat these orderings somewhat differently since they don't take an address.
1661See that instruction's documentation for details.</p>
1662
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1663<p>For a simpler introduction to the ordering constraints, see the
1664<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1665
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1666<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1667<dt><code>unordered</code></dt>
1668<dd>The set of values that can be read is governed by the happens-before
1669partial order. A value cannot be read unless some operation wrote it.
1670This is intended to provide a guarantee strong enough to model Java's
1671non-volatile shared variables. This ordering cannot be specified for
1672read-modify-write operations; it is not strong enough to make them atomic
1673in any interesting way.</dd>
1674<dt><code>monotonic</code></dt>
1675<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1676total order for modifications by <code>monotonic</code> operations on each
1677address. All modification orders must be compatible with the happens-before
1678order. There is no guarantee that the modification orders can be combined to
1679a global total order for the whole program (and this often will not be
1680possible). The read in an atomic read-modify-write operation
1681(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1682<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1683reads the value in the modification order immediately before the value it
1684writes. If one atomic read happens before another atomic read of the same
1685address, the later read must see the same value or a later value in the
1686address's modification order. This disallows reordering of
1687<code>monotonic</code> (or stronger) operations on the same address. If an
1688address is written <code>monotonic</code>ally by one thread, and other threads
1689<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1690eventually see the write. This corresponds to the C++0x/C1x
1691<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1692<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1693<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1694a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1695operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1696<dt><code>release</code></dt>
1697<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1698writes a value which is subsequently read by an <code>acquire</code> operation,
1699it <i>synchronizes-with</i> that operation. (This isn't a complete
1700description; see the C++0x definition of a release sequence.) This corresponds
1701to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1702<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1703<code>acquire</code> and <code>release</code> operation on its address.
1704This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1705<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1706<dd>In addition to the guarantees of <code>acq_rel</code>
1707(<code>acquire</code> for an operation which only reads, <code>release</code>
1708for an operation which only writes), there is a global total order on all
1709sequentially-consistent operations on all addresses, which is consistent with
1710the <i>happens-before</i> partial order and with the modification orders of
1711all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1712preceding write to the same address in this global order. This corresponds
1713to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1714</dl>
1715
1716<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1717it only <i>synchronizes with</i> or participates in modification and seq_cst
1718total orderings with other operations running in the same thread (for example,
1719in signal handlers).</p>
1720
1721</div>
1722
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1723</div>
1724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1725<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1726<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1727<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1728
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1729<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1730
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1731<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1732 intermediate representation. Being typed enables a number of optimizations
1733 to be performed on the intermediate representation directly, without having
1734 to do extra analyses on the side before the transformation. A strong type
1735 system makes it easier to read the generated code and enables novel analyses
1736 and transformations that are not feasible to perform on normal three address
1737 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1738
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1739<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1740<h3>
1741 <a name="t_classifications">Type Classifications</a>
1742</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1743
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1744<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1745
1746<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1747
1748<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1749 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1750 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1751 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1752 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1753 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1754 </tr>
1755 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1756 <td><a href="#t_floating">floating point</a></td>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1757 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1758 </tr>
1759 <tr>
1760 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1761 <td><a href="#t_integer">integer</a>,
1762 <a href="#t_floating">floating point</a>,
1763 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1764 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1765 <a href="#t_struct">structure</a>,
1766 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1767 <a href="#t_label">label</a>,
1768 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1769 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1770 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1771 <tr>
1772 <td><a href="#t_primitive">primitive</a></td>
1773 <td><a href="#t_label">label</a>,
1774 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1775 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1776 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1777 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1778 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1779 </tr>
1780 <tr>
1781 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1782 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1783 <a href="#t_function">function</a>,
1784 <a href="#t_pointer">pointer</a>,
1785 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1786 <a href="#t_vector">vector</a>,
1787 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1788 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1789 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1790 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1791</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1792
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1793<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1794 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1795 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1796
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1797</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1798
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1800<h3>
1801 <a name="t_primitive">Primitive Types</a>
1802</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1803
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1804<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1806<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1807 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1808
1809<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1810<h4>
1811 <a name="t_integer">Integer Type</a>
1812</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1813
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1814<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1815
1816<h5>Overview:</h5>
1817<p>The integer type is a very simple type that simply specifies an arbitrary
1818 bit width for the integer type desired. Any bit width from 1 bit to
1819 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1820
1821<h5>Syntax:</h5>
1822<pre>
1823 iN
1824</pre>
1825
1826<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1827 value.</p>
1828
1829<h5>Examples:</h5>
1830<table class="layout">
1831 <tr class="layout">
1832 <td class="left"><tt>i1</tt></td>
1833 <td class="left">a single-bit integer.</td>
1834 </tr>
1835 <tr class="layout">
1836 <td class="left"><tt>i32</tt></td>
1837 <td class="left">a 32-bit integer.</td>
1838 </tr>
1839 <tr class="layout">
1840 <td class="left"><tt>i1942652</tt></td>
1841 <td class="left">a really big integer of over 1 million bits.</td>
1842 </tr>
1843</table>
1844
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1845</div>
1846
1847<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1848<h4>
1849 <a name="t_floating">Floating Point Types</a>
1850</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1851
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1852<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1853
1854<table>
1855 <tbody>
1856 <tr><th>Type</th><th>Description</th></tr>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1857 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1858 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1859 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1860 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1861 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1862 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1863 </tbody>
1864</table>
1865
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1866</div>
1867
1868<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1869<h4>
1870 <a name="t_x86mmx">X86mmx Type</a>
1871</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1872
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1873<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1874
1875<h5>Overview:</h5>
1876<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>
1877
1878<h5>Syntax:</h5>
1879<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1880 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1881</pre>
1882
1883</div>
1884
1885<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1886<h4>
1887 <a name="t_void">Void Type</a>
1888</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1890<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1891
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1892<h5>Overview:</h5>
1893<p>The void type does not represent any value and has no size.</p>
1894
1895<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1896<pre>
1897 void
1898</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1899
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1900</div>
1901
1902<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1903<h4>
1904 <a name="t_label">Label Type</a>
1905</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1906
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1907<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1908
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1909<h5>Overview:</h5>
1910<p>The label type represents code labels.</p>
1911
1912<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1913<pre>
1914 label
1915</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1916
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1917</div>
1918
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1919<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1920<h4>
1921 <a name="t_metadata">Metadata Type</a>
1922</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1923
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1924<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1925
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1926<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1927<p>The metadata type represents embedded metadata. No derived types may be
1928 created from metadata except for <a href="#t_function">function</a>
1929 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1930
1931<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1932<pre>
1933 metadata
1934</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1935
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1936</div>
1937
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1938</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1939
1940<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1941<h3>
1942 <a name="t_derived">Derived Types</a>
1943</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1944
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1945<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1946
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1947<p>The real power in LLVM comes from the derived types in the system. This is
1948 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1949 useful types. Each of these types contain one or more element types which
1950 may be a primitive type, or another derived type. For example, it is
1951 possible to have a two dimensional array, using an array as the element type
1952 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1953
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1954<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1955<h4>
1956 <a name="t_aggregate">Aggregate Types</a>
1957</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1958
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1959<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1960
1961<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands9aaec152011-12-14 15:44:20 +0000[diff] [blame]1962 member types. <a href="#t_array">Arrays</a> and
1963 <a href="#t_struct">structs</a> are aggregate types.
1964 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1965
1966</div>
1967
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1968<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1969<h4>
1970 <a name="t_array">Array Type</a>
1971</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1972
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1973<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1976<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1977 sequentially in memory. The array type requires a size (number of elements)
1978 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1979
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1980<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1981<pre>
1982 [&lt;# elements&gt; x &lt;elementtype&gt;]
1983</pre>
1984
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1985<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1986 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1987
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1988<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1989<table class="layout">
1990 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1991 <td class="left"><tt>[40 x i32]</tt></td>
1992 <td class="left">Array of 40 32-bit integer values.</td>
1993 </tr>
1994 <tr class="layout">
1995 <td class="left"><tt>[41 x i32]</tt></td>
1996 <td class="left">Array of 41 32-bit integer values.</td>
1997 </tr>
1998 <tr class="layout">
1999 <td class="left"><tt>[4 x i8]</tt></td>
2000 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2001 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2002</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2003<p>Here are some examples of multidimensional arrays:</p>
2004<table class="layout">
2005 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2006 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
2007 <td class="left">3x4 array of 32-bit integer values.</td>
2008 </tr>
2009 <tr class="layout">
2010 <td class="left"><tt>[12 x [10 x float]]</tt></td>
2011 <td class="left">12x10 array of single precision floating point values.</td>
2012 </tr>
2013 <tr class="layout">
2014 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
2015 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2016 </tr>
2017</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2018
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]2019<p>There is no restriction on indexing beyond the end of the array implied by
2020 a static type (though there are restrictions on indexing beyond the bounds
2021 of an allocated object in some cases). This means that single-dimension
2022 'variable sized array' addressing can be implemented in LLVM with a zero
2023 length array type. An implementation of 'pascal style arrays' in LLVM could
2024 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2025
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2026</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2027
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2028<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2029<h4>
2030 <a name="t_function">Function Type</a>
2031</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2032
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2033<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2034
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2035<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2036<p>The function type can be thought of as a function signature. It consists of
2037 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]2038 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]2039
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2041<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2042 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2043</pre>
2044
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2045<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]2046 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2047 which indicates that the function takes a variable number of arguments.
2048 Variable argument functions can access their arguments with
2049 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2050 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2051 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2052
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2053<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2054<table class="layout">
2055 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2056 <td class="left"><tt>i32 (i32)</tt></td>
2057 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2058 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2059 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2060 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2061 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2062 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2063 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2064 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2065 </td>
2066 </tr><tr class="layout">
2067 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2068 <td class="left">A vararg function that takes at least one
2069 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2070 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2071 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2072 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2073 </tr><tr class="layout">
2074 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2075 <td class="left">A function taking an <tt>i32</tt>, returning a
2076 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2077 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2078 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2079</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2080
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2081</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2082
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2083<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2084<h4>
2085 <a name="t_struct">Structure Type</a>
2086</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2087
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2088<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2090<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2091<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2092 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]2093
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2094<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2095 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2096 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2097 Structures in registers are accessed using the
2098 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2099 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2100
2101<p>Structures may optionally be "packed" structures, which indicate that the
2102 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2103 the elements. In non-packed structs, padding between field types is inserted
2104 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2105 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2106
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2107<p>Structures can either be "literal" or "identified". A literal structure is
2108 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2109 types are always defined at the top level with a name. Literal types are
2110 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2111 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]2112 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2113</p>
2114
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2115<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2116<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2117 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2118 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2119</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2122<table class="layout">
2123 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2124 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2125 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2126 </tr>
2127 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2128 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2129 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2130 second element is a <a href="#t_pointer">pointer</a> to a
2131 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2132 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2133 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2134 <tr class="layout">
2135 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2136 <td class="left">A packed struct known to be 5 bytes in size.</td>
2137 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2138</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2139
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2140</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2141
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2142<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2143<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2144 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2145</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2146
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2147<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2148
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2149<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2150<p>Opaque structure types are used to represent named structure types that do
2151 not have a body specified. This corresponds (for example) to the C notion of
2152 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2153
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2154<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2155<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2156 %X = type opaque
2157 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2158</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2159
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2160<h5>Examples:</h5>
2161<table class="layout">
2162 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2163 <td class="left"><tt>opaque</tt></td>
2164 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2165 </tr>
2166</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2167
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2168</div>
2169
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2170
2171
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_pointer">Pointer Type</a>
2175</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2176
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2178
2179<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2180<p>The pointer type is used to specify memory locations.
2181 Pointers are commonly used to reference objects in memory.</p>
2182
2183<p>Pointer types may have an optional address space attribute defining the
2184 numbered address space where the pointed-to object resides. The default
2185 address space is number zero. The semantics of non-zero address
2186 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2187
2188<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2189 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2190
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2191<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2192<pre>
2193 &lt;type&gt; *
2194</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2196<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2197<table class="layout">
2198 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2199 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2200 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2201 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2202 </tr>
2203 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2204 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2205 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2206 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2207 <tt>i32</tt>.</td>
2208 </tr>
2209 <tr class="layout">
2210 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2211 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2212 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2213 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2214</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2216</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2217
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2218<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2219<h4>
2220 <a name="t_vector">Vector Type</a>
2221</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2222
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2223<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2224
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2225<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2226<p>A vector type is a simple derived type that represents a vector of elements.
2227 Vector types are used when multiple primitive data are operated in parallel
2228 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2229 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2230 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2231
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2232<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2233<pre>
2234 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2235</pre>
2236
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2237<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2238 may be any integer or floating point type, or a pointer to these types.
2239 Vectors of size zero are not allowed. </p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2240
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2241<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2242<table class="layout">
2243 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2244 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2245 <td class="left">Vector of 4 32-bit integer values.</td>
2246 </tr>
2247 <tr class="layout">
2248 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2249 <td class="left">Vector of 8 32-bit floating-point values.</td>
2250 </tr>
2251 <tr class="layout">
2252 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2253 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2254 </tr>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2255 <tr class="layout">
2256 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2257 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2258 </tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2259</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2260
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2261</div>
2262
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2263</div>
2264
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2265</div>
2266
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2267<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2268<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2269<!-- *********************************************************************** -->
2270
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2271<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2272
2273<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2274 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2275
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2276<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2277<h3>
2278 <a name="simpleconstants">Simple Constants</a>
2279</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2280
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2281<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2282
2283<dl>
2284 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2285 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2286 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2287
2288 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2289 <dd>Standard integers (such as '4') are constants of
2290 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2291 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2292
2293 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2294 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2295 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2296 notation (see below). The assembler requires the exact decimal value of a
2297 floating-point constant. For example, the assembler accepts 1.25 but
2298 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2299 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2300
2301 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2302 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2303 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2304</dl>
2305
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2306<p>The one non-intuitive notation for constants is the hexadecimal form of
2307 floating point constants. For example, the form '<tt>double
2308 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2309 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2310 constants are required (and the only time that they are generated by the
2311 disassembler) is when a floating point constant must be emitted but it cannot
2312 be represented as a decimal floating point number in a reasonable number of
2313 digits. For example, NaN's, infinities, and other special values are
2314 represented in their IEEE hexadecimal format so that assembly and disassembly
2315 do not cause any bits to change in the constants.</p>
2316
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2317<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2318 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2319 representation for double); half and float values must, however, be exactly
2320 representable as IEE754 half and single precision, respectively.
2321 Hexadecimal format is always used
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2322 for long double, and there are three forms of long double. The 80-bit format
2323 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2324 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2325 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2326 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2327 currently supported target uses this format. Long doubles will only work if
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]2328 they match the long double format on your target. The IEEE 16-bit format
2329 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2330 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2331
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2332<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2333</div>
2334
2335<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2336<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2337<a name="aggregateconstants"></a> <!-- old anchor -->
2338<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2339</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2340
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2341<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2342
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2343<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2344 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2345
2346<dl>
2347 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2348 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2349 type definitions (a comma separated list of elements, surrounded by braces
2350 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2351 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2352 Structure constants must have <a href="#t_struct">structure type</a>, and
2353 the number and types of elements must match those specified by the
2354 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2355
2356 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2357 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2358 definitions (a comma separated list of elements, surrounded by square
2359 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2360 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2361 the number and types of elements must match those specified by the
2362 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2363
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2364 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2365 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2366 definitions (a comma separated list of elements, surrounded by
2367 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2368 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2369 have <a href="#t_vector">vector type</a>, and the number and types of
2370 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2371
2372 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2373 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2374 value to zero of <em>any</em> type, including scalar and
2375 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2376 This is often used to avoid having to print large zero initializers
2377 (e.g. for large arrays) and is always exactly equivalent to using explicit
2378 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2379
2380 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2381 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2382 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2383 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2384 be interpreted as part of the instruction stream, metadata is a place to
2385 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2386</dl>
2387
2388</div>
2389
2390<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2391<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2392 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2393</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2394
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2395<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2396
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2397<p>The addresses of <a href="#globalvars">global variables</a>
2398 and <a href="#functionstructure">functions</a> are always implicitly valid
2399 (link-time) constants. These constants are explicitly referenced when
2400 the <a href="#identifiers">identifier for the global</a> is used and always
2401 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2402 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2403
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2404<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2405@X = global i32 17
2406@Y = global i32 42
2407@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2408</pre>
2409
2410</div>
2411
2412<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2413<h3>
2414 <a name="undefvalues">Undefined Values</a>
2415</h3>
2416
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2417<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2418
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2419<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]2420 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2421 Undefined values may be of any type (other than '<tt>label</tt>'
2422 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2423
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2424<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2425 program is well defined no matter what value is used. This gives the
2426 compiler more freedom to optimize. Here are some examples of (potentially
2427 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2428
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2429
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2430<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2431 %A = add %X, undef
2432 %B = sub %X, undef
2433 %C = xor %X, undef
2434Safe:
2435 %A = undef
2436 %B = undef
2437 %C = undef
2438</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2439
2440<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]2441 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]2442
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2443<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2444 %A = or %X, undef
2445 %B = and %X, undef
2446Safe:
2447 %A = -1
2448 %B = 0
2449Unsafe:
2450 %A = undef
2451 %B = undef
2452</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2453
2454<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2455 For example, if <tt>%X</tt> has a zero bit, then the output of the
2456 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2457 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2458 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2459 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2460 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2461 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2462 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2463
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2464<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2465 %A = select undef, %X, %Y
2466 %B = select undef, 42, %Y
2467 %C = select %X, %Y, undef
2468Safe:
2469 %A = %X (or %Y)
2470 %B = 42 (or %Y)
2471 %C = %Y
2472Unsafe:
2473 %A = undef
2474 %B = undef
2475 %C = undef
2476</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2477
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2478<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2479 branch) conditions can go <em>either way</em>, but they have to come from one
2480 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2481 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2482 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2483 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2484 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2485 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2486
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2487<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2488 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2489
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2490 %B = undef
2491 %C = xor %B, %B
2492
2493 %D = undef
2494 %E = icmp lt %D, 4
2495 %F = icmp gte %D, 4
2496
2497Safe:
2498 %A = undef
2499 %B = undef
2500 %C = undef
2501 %D = undef
2502 %E = undef
2503 %F = undef
2504</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2505
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2506<p>This example points out that two '<tt>undef</tt>' operands are not
2507 necessarily the same. This can be surprising to people (and also matches C
2508 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2509 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2510 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2511 its value over its "live range". This is true because the variable doesn't
2512 actually <em>have a live range</em>. Instead, the value is logically read
2513 from arbitrary registers that happen to be around when needed, so the value
2514 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2515 need to have the same semantics or the core LLVM "replace all uses with"
2516 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2517
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2518<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2519 %A = fdiv undef, %X
2520 %B = fdiv %X, undef
2521Safe:
2522 %A = undef
2523b: unreachable
2524</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2525
2526<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2527 value</em> and <em>undefined behavior</em>. An undefined value (like
2528 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2529 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2530 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2531 defined on SNaN's. However, in the second example, we can make a more
2532 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2533 arbitrary value, we are allowed to assume that it could be zero. Since a
2534 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2535 the operation does not execute at all. This allows us to delete the divide and
2536 all code after it. Because the undefined operation "can't happen", the
2537 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2538
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2539<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2540a: store undef -> %X
2541b: store %X -> undef
2542Safe:
2543a: &lt;deleted&gt;
2544b: unreachable
2545</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2546
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2547<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2548 undefined value can be assumed to not have any effect; we can assume that the
2549 value is overwritten with bits that happen to match what was already there.
2550 However, a store <em>to</em> an undefined location could clobber arbitrary
2551 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2552
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2553</div>
2554
2555<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2556<h3>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2557 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2558</h3>
2559
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2560<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2561
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2562<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2563 they also represent the fact that an instruction or constant expression which
2564 cannot evoke side effects has nevertheless detected a condition which results
2565 in undefined behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2566
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2567<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]2568 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2569 <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]2570
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2571<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2572
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2573<ul>
2574<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2575 their operands.</li>
2576
2577<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2578 to their dynamic predecessor basic block.</li>
2579
2580<li>Function arguments depend on the corresponding actual argument values in
2581 the dynamic callers of their functions.</li>
2582
2583<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2584 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2585 control back to them.</li>
2586
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2587<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]2588 <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]2589 or exception-throwing call instructions that dynamically transfer control
2590 back to them.</li>
2591
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2592<li>Non-volatile loads and stores depend on the most recent stores to all of the
2593 referenced memory addresses, following the order in the IR
2594 (including loads and stores implied by intrinsics such as
2595 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2596
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2597<!-- TODO: In the case of multiple threads, this only applies if the store
2598 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2599
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2600<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2601
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2602<li>An instruction with externally visible side effects depends on the most
2603 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2604 the order in the IR. (This includes
2605 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2606
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2607<li>An instruction <i>control-depends</i> on a
2608 <a href="#terminators">terminator instruction</a>
2609 if the terminator instruction has multiple successors and the instruction
2610 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2611 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2612
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2613<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2614 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2615 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2616 successor.</li>
2617
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2618<li>Dependence is transitive.</li>
2619
2620</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2621
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2622<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2623 with the additional affect that any instruction which has a <i>dependence</i>
2624 on a poison value has undefined behavior.</p>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2625
2626<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2627
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2629entry:
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2630 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2631 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2632 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2633 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2634
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2635 store i32 %poison, i32* @g ; Poison value stored to memory.
2636 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2637
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2638 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2639
2640 %narrowaddr = bitcast i32* @g to i16*
2641 %wideaddr = bitcast i32* @g to i64*
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2642 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2643 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2644
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2645 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2646 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2647
2648true:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2649 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2650 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2651 br label %end
2652
2653end:
2654 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2655 ; Both edges into this PHI are
2656 ; control-dependent on %cmp, so this
2657 ; always results in a poison value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2658
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2659 store volatile i32 0, i32* @g ; This would depend on the store in %true
2660 ; if %cmp is true, or the store in %entry
2661 ; otherwise, so this is undefined behavior.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2662
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2663 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2664 ; The same branch again, but this time the
2665 ; true block doesn't have side effects.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2666
2667second_true:
2668 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2669 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2670
2671second_end:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2672 store volatile i32 0, i32* @g ; This time, the instruction always depends
2673 ; on the store in %end. Also, it is
2674 ; control-equivalent to %end, so this is
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2675 ; well-defined (ignoring earlier undefined
2676 ; behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2677</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2678
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2679</div>
2680
2681<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2682<h3>
2683 <a name="blockaddress">Addresses of Basic Blocks</a>
2684</h3>
2685
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2686<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2687
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2688<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2689
2690<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2691 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2692 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2693
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2694<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2695 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2696 comparisons against null. Pointer equality tests between labels addresses
2697 results in undefined behavior &mdash; though, again, comparison against null
2698 is ok, and no label is equal to the null pointer. This may be passed around
2699 as an opaque pointer sized value as long as the bits are not inspected. This
2700 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2701 long as the original value is reconstituted before the <tt>indirectbr</tt>
2702 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2703
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2704<p>Finally, some targets may provide defined semantics when using the value as
2705 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2706
2707</div>
2708
2709
2710<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2711<h3>
2712 <a name="constantexprs">Constant Expressions</a>
2713</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2714
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2715<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2716
2717<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2718 to be used as constants. Constant expressions may be of
2719 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2720 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2721 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2722
2723<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2725 <dd>Truncate a constant to another type. The bit size of CST must be larger
2726 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2727
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2729 <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]2730 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2731
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2732 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2733 <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]2734 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2735
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2736 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2737 <dd>Truncate a floating point constant to another floating point type. The
2738 size of CST must be larger than the size of TYPE. Both types must be
2739 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2740
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2741 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2742 <dd>Floating point extend a constant to another type. The size of CST must be
2743 smaller or equal to the size of TYPE. Both types must be floating
2744 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2745
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2746 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2747 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2748 constant. TYPE must be a scalar or vector integer type. CST must be of
2749 scalar or vector floating point type. Both CST and TYPE must be scalars,
2750 or vectors of the same number of elements. If the value won't fit in the
2751 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2752
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2753 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2754 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2755 constant. TYPE must be a scalar or vector integer type. CST must be of
2756 scalar or vector floating point type. Both CST and TYPE must be scalars,
2757 or vectors of the same number of elements. If the value won't fit in the
2758 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2759
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2761 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2762 constant. TYPE must be a scalar or vector floating point type. CST must be
2763 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2764 vectors of the same number of elements. If the value won't fit in the
2765 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2766
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2767 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2768 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2769 constant. TYPE must be a scalar or vector floating point type. CST must be
2770 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2771 vectors of the same number of elements. If the value won't fit in the
2772 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2773
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2774 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2775 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2776 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2777 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2778 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2779
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2780 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2781 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2782 type. CST must be of integer type. The CST value is zero extended,
2783 truncated, or unchanged to make it fit in a pointer size. This one is
2784 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2785
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2786 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2787 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2788 are the same as those for the <a href="#i_bitcast">bitcast
2789 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2790
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2791 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2792 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2793 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2794 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2795 instruction, the index list may have zero or more indexes, which are
2796 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2797
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2798 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2799 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2800
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2801 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2802 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2803
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2804 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2805 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2806
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2807 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2808 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2809 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2810
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2811 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2812 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2813 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2814
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2815 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2817 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2818
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2819 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2820 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2821 constants. The index list is interpreted in a similar manner as indices in
2822 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2823 index value must be specified.</dd>
2824
2825 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2826 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2827 constants. The index list is interpreted in a similar manner as indices in
2828 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2829 index value must be specified.</dd>
2830
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2831 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2832 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2833 be any of the <a href="#binaryops">binary</a>
2834 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2835 on operands are the same as those for the corresponding instruction
2836 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2837</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2838
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2839</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2840
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2841</div>
2842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2843<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2844<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2845<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2846<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2847<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2848<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2849<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2850</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2851
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2852<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2853
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2854<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2855 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2856 a special value. This value represents the inline assembler as a string
2857 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2858 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2859 expression has side effects, and a flag indicating whether the function
2860 containing the asm needs to align its stack conservatively. An example
2861 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2862
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2863<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2864i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2865</pre>
2866
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2867<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2868 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2869 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2870
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2871<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2872%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]2873</pre>
2874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2875<p>Inline asms with side effects not visible in the constraint list must be
2876 marked as having side effects. This is done through the use of the
2877 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2878
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2879<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2880call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2881</pre>
2882
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2883<p>In some cases inline asms will contain code that will not work unless the
2884 stack is aligned in some way, such as calls or SSE instructions on x86,
2885 yet will not contain code that does that alignment within the asm.
2886 The compiler should make conservative assumptions about what the asm might
2887 contain and should generate its usual stack alignment code in the prologue
2888 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2889
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2890<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2891call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2892</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2893
2894<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2895 first.</p>
2896
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2897<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2898<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2899 documented here. Constraints on what can be done (e.g. duplication, moving,
2900 etc need to be documented). This is probably best done by reference to
2901 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2902 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2903
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2905<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2906 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2907</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2908
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2909<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2910
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2911<p>The call instructions that wrap inline asm nodes may have a
2912 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2913 integers. If present, the code generator will use the integer as the
2914 location cookie value when report errors through the <tt>LLVMContext</tt>
2915 error reporting mechanisms. This allows a front-end to correlate backend
2916 errors that occur with inline asm back to the source code that produced it.
2917 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2918
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2919<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2920call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2921...
2922!42 = !{ i32 1234567 }
2923</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2924
2925<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]2926 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2927 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]2928
2929</div>
2930
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2931</div>
2932
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2933<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2934<h3>
2935 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2936</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2937
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2938<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2939
2940<p>LLVM IR allows metadata to be attached to instructions in the program that
2941 can convey extra information about the code to the optimizers and code
2942 generator. One example application of metadata is source-level debug
2943 information. There are two metadata primitives: strings and nodes. All
2944 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2945 preceding exclamation point ('<tt>!</tt>').</p>
2946
2947<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2948 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2949 "<tt>xx</tt>" is the two digit hex code. For example:
2950 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2951
2952<p>Metadata nodes are represented with notation similar to structure constants
2953 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2954 exclamation point). Metadata nodes can have any values as their operand. For
2955 example:</p>
2956
2957<div class="doc_code">
2958<pre>
2959!{ metadata !"test\00", i32 10}
2960</pre>
2961</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2962
2963<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2964 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2965 example:</p>
2966
2967<div class="doc_code">
2968<pre>
2969!foo = metadata !{!4, !3}
2970</pre>
2971</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2972
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2973<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2974 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2975
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2976<div class="doc_code">
2977<pre>
2978call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2979</pre>
2980</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2981
2982<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2983 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2984 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2985
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2986<div class="doc_code">
2987<pre>
2988%indvar.next = add i64 %indvar, 1, !dbg !21
2989</pre>
2990</div>
2991
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2992<p>More information about specific metadata nodes recognized by the optimizers
2993 and code generator is found below.</p>
2994
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2995<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2996<h4>
2997 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2998</h4>
2999
3000<div>
3001
3002<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
3003 suitable for doing TBAA. Instead, metadata is added to the IR to describe
3004 a type system of a higher level language. This can be used to implement
3005 typical C/C++ TBAA, but it can also be used to implement custom alias
3006 analysis behavior for other languages.</p>
3007
3008<p>The current metadata format is very simple. TBAA metadata nodes have up to
3009 three fields, e.g.:</p>
3010
3011<div class="doc_code">
3012<pre>
3013!0 = metadata !{ metadata !"an example type tree" }
3014!1 = metadata !{ metadata !"int", metadata !0 }
3015!2 = metadata !{ metadata !"float", metadata !0 }
3016!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
3017</pre>
3018</div>
3019
3020<p>The first field is an identity field. It can be any value, usually
3021 a metadata string, which uniquely identifies the type. The most important
3022 name in the tree is the name of the root node. Two trees with
3023 different root node names are entirely disjoint, even if they
3024 have leaves with common names.</p>
3025
3026<p>The second field identifies the type's parent node in the tree, or
3027 is null or omitted for a root node. A type is considered to alias
3028 all of its descendants and all of its ancestors in the tree. Also,
3029 a type is considered to alias all types in other trees, so that
3030 bitcode produced from multiple front-ends is handled conservatively.</p>
3031
3032<p>If the third field is present, it's an integer which if equal to 1
3033 indicates that the type is "constant" (meaning
3034 <tt>pointsToConstantMemory</tt> should return true; see
3035 <a href="AliasAnalysis.html#OtherItfs">other useful
3036 <tt>AliasAnalysis</tt> methods</a>).</p>
3037
3038</div>
3039
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]3040<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3041<h4>
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3042 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3043</h4>
3044
3045<div>
3046
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3047<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3048 type. It can be used to express the maximum acceptable error in the result of
3049 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3050 more efficient but less accurate method of computing it. ULP is defined as
3051 follows:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3052
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]3053<blockquote>
3054
3055<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3056 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3057 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3058 distance between the two non-equal finite floating-point numbers nearest
3059 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3060
3061</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3062
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3063<p>The metadata node shall consist of a single positive floating point number
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3064 representing the maximum relative error, for example:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3065
3066<div class="doc_code">
3067<pre>
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3068!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3069</pre>
3070</div>
3071
NAKAMURA Takumic9d9b922012-03-27 11:25:16 +0000[diff] [blame]3072</div>
3073
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3074<!-- _______________________________________________________________________ -->
3075<h4>
3076 <a name="range">'<tt>range</tt>' Metadata</a>
3077</h4>
3078
3079<div>
3080<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3081 expresses the possible ranges the loaded value is in. The ranges are
3082 represented with a flattened list of integers. The loaded value is known to
3083 be in the union of the ranges defined by each consecutive pair. Each pair
3084 has the following properties:</p>
3085<ul>
3086 <li>The type must match the type loaded by the instruction.</li>
3087 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3088 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3089 <li>The range is allowed to wrap.</li>
3090 <li>The range should not represent the full or empty set. That is,
3091 <tt>a!=b</tt>. </li>
3092</ul>
Rafael Espindolae3c5f3e2012-05-31 16:04:26 +0000[diff] [blame]3093<p> In addition, the pairs must be in signed order of the lower bound and
3094 they must be non-contiguous.</p>
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3095
3096<p>Examples:</p>
3097<div class="doc_code">
3098<pre>
3099 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3100 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3101 %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]3102 %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]3103...
3104!0 = metadata !{ i8 0, i8 2 }
3105!1 = metadata !{ i8 255, i8 2 }
3106!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindola97d77872012-05-31 13:45:46 +0000[diff] [blame]3107!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3108</pre>
3109</div>
3110</div>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3111</div>
3112
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3113</div>
3114
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3115<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3116<h2>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3117 <a name="module_flags">Module Flags Metadata</a>
3118</h2>
3119<!-- *********************************************************************** -->
3120
3121<div>
3122
3123<p>Information about the module as a whole is difficult to convey to LLVM's
3124 subsystems. The LLVM IR isn't sufficient to transmit this
3125 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3126 facilitate this. These flags are in the form of key / value pairs &mdash;
3127 much like a dictionary &mdash; making it easy for any subsystem who cares
3128 about a flag to look it up.</p>
3129
3130<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3131 triplets. Each triplet has the following form:</p>
3132
3133<ul>
3134 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3135 when two (or more) modules are merged together, and it encounters two (or
3136 more) metadata with the same ID. The supported behaviors are described
3137 below.</li>
3138
3139 <li>The second element is a metadata string that is a unique ID for the
3140 metadata. How each ID is interpreted is documented below.</li>
3141
3142 <li>The third element is the value of the flag.</li>
3143</ul>
3144
3145<p>When two (or more) modules are merged together, the resulting
3146 <tt>llvm.module.flags</tt> metadata is the union of the
3147 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3148 with the <i>Override</i> behavior, which may override another flag's value
3149 (see below).</p>
3150
3151<p>The following behaviors are supported:</p>
3152
3153<table border="1" cellspacing="0" cellpadding="4">
3154 <tbody>
3155 <tr>
3156 <th>Value</th>
3157 <th>Behavior</th>
3158 </tr>
3159 <tr>
3160 <td>1</td>
3161 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3162 <dl>
3163 <dt><b>Error</b></dt>
3164 <dd>Emits an error if two values disagree. It is an error to have an ID
3165 with both an Error and a Warning behavior.</dd>
3166 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3167 </td>
3168 </tr>
3169 <tr>
3170 <td>2</td>
3171 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3172 <dl>
3173 <dt><b>Warning</b></dt>
3174 <dd>Emits a warning if two values disagree.</dd>
3175 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3176 </td>
3177 </tr>
3178 <tr>
3179 <td>3</td>
3180 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3181 <dl>
3182 <dt><b>Require</b></dt>
3183 <dd>Emits an error when the specified value is not present or doesn't
3184 have the specified value. It is an error for two (or more)
3185 <tt>llvm.module.flags</tt> with the same ID to have the Require
3186 behavior but different values. There may be multiple Require flags
3187 per ID.</dd>
3188 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3189 </td>
3190 </tr>
3191 <tr>
3192 <td>4</td>
3193 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3194 <dl>
3195 <dt><b>Override</b></dt>
3196 <dd>Uses the specified value if the two values disagree. It is an
3197 error for two (or more) <tt>llvm.module.flags</tt> with the same
3198 ID to have the Override behavior but different values.</dd>
3199 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3200 </td>
3201 </tr>
3202 </tbody>
3203</table>
3204
3205<p>An example of module flags:</p>
3206
3207<pre class="doc_code">
3208!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3209!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3210!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3211!3 = metadata !{ i32 3, metadata !"qux",
3212 metadata !{
3213 metadata !"foo", i32 1
3214 }
3215}
3216!llvm.module.flags = !{ !0, !1, !2, !3 }
3217</pre>
3218
3219<ul>
3220 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3221 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3222 error if their values are not equal.</p></li>
3223
3224 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3225 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3226 value '37' if their values are not equal.</p></li>
3227
3228 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3229 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3230 warning if their values are not equal.</p></li>
3231
3232 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3233
3234<pre class="doc_code">
3235metadata !{ metadata !"foo", i32 1 }
3236</pre>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3237
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3238 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3239 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3240 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3241 the same value or an error will be issued.</p></li>
3242</ul>
3243
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3244
3245<!-- ======================================================================= -->
3246<h3>
3247<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3248</h3>
3249
3250<div>
3251
3252<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3253 in a special section called "image info". The metadata consists of a version
3254 number and a bitmask specifying what types of garbage collection are
3255 supported (if any) by the file. If two or more modules are linked together
3256 their garbage collection metadata needs to be merged rather than appended
3257 together.</p>
3258
3259<p>The Objective-C garbage collection module flags metadata consists of the
3260 following key-value pairs:</p>
3261
3262<table border="1" cellspacing="0" cellpadding="4">
Bill Wendling4fa13cc2012-03-06 09:23:25 +0000[diff] [blame]3263 <col width="30%">
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3264 <tbody>
3265 <tr>
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3266 <th>Key</th>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3267 <th>Value</th>
3268 </tr>
3269 <tr>
3270 <td><tt>Objective-C&nbsp;Version</tt></td>
3271 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3272 version. Valid values are 1 and 2.</td>
3273 </tr>
3274 <tr>
3275 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3276 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3277 section. Currently always 0.</td>
3278 </tr>
3279 <tr>
3280 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3281 <td align="left"><b>[Required]</b> &mdash; The section to place the
3282 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3283 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3284 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3285 </tr>
3286 <tr>
3287 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3288 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3289 collection is supported or not. Valid values are 0, for no garbage
3290 collection, and 2, for garbage collection supported.</td>
3291 </tr>
3292 <tr>
3293 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3294 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3295 collection is supported. If present, its value must be 6. This flag
3296 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3297 value 2.</td>
3298 </tr>
3299 </tbody>
3300</table>
3301
3302<p>Some important flag interactions:</p>
3303
3304<ul>
3305 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3306 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3307 2, then the resulting module has the <tt>Objective-C Garbage
3308 Collection</tt> flag set to 0.</li>
3309
3310 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3311 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3312</ul>
3313
3314</div>
3315
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3316</div>
3317
3318<!-- *********************************************************************** -->
3319<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3320 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3321</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3322<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3323<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3324<p>LLVM has a number of "magic" global variables that contain data that affect
3325code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3326of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3327section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3328by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3329
3330<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3331<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3332<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3333</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3334
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3335<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3336
3337<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3338href="#linkage_appending">appending linkage</a>. This array contains a list of
3339pointers to global variables and functions which may optionally have a pointer
3340cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3341
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3342<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3343<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3344@X = global i8 4
3345@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3346
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3347@llvm.used = appending global [2 x i8*] [
3348 i8* @X,
3349 i8* bitcast (i32* @Y to i8*)
3350], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3351</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3352</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3353
3354<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]3355 compiler, assembler, and linker are required to treat the symbol as if there
3356 is a reference to the global that it cannot see. For example, if a variable
3357 has internal linkage and no references other than that from
3358 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3359 represent references from inline asms and other things the compiler cannot
3360 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3361
3362<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]3363 object file to prevent the assembler and linker from molesting the
3364 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3365
3366</div>
3367
3368<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3369<h3>
3370 <a name="intg_compiler_used">
3371 The '<tt>llvm.compiler.used</tt>' Global Variable
3372 </a>
3373</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3374
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3375<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3376
3377<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3378 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3379 touching the symbol. On targets that support it, this allows an intelligent
3380 linker to optimize references to the symbol without being impeded as it would
3381 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3382
3383<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]3384 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3385
3386</div>
3387
3388<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3389<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3390<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3391</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3392
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3393<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3394
3395<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3396<pre>
3397%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3398@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3399</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3400</div>
3401
3402<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3403 functions and associated priorities. The functions referenced by this array
3404 will be called in ascending order of priority (i.e. lowest first) when the
3405 module is loaded. The order of functions with the same priority is not
3406 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3407
3408</div>
3409
3410<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3411<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3412<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3413</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3414
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3415<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3416
3417<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3418<pre>
3419%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3420@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3421</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3422</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3423
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3424<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3425 and associated priorities. The functions referenced by this array will be
3426 called in descending order of priority (i.e. highest first) when the module
3427 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3428
3429</div>
3430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3431</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3432
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3433<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3434<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3435<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3436
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3437<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3438
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439<p>The LLVM instruction set consists of several different classifications of
3440 instructions: <a href="#terminators">terminator
3441 instructions</a>, <a href="#binaryops">binary instructions</a>,
3442 <a href="#bitwiseops">bitwise binary instructions</a>,
3443 <a href="#memoryops">memory instructions</a>, and
3444 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3446<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3447<h3>
3448 <a name="terminators">Terminator Instructions</a>
3449</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3450
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3451<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3452
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3454 in a program ends with a "Terminator" instruction, which indicates which
3455 block should be executed after the current block is finished. These
3456 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3457 control flow, not values (the one exception being the
3458 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3459
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3460<p>The terminator instructions are:
3461 '<a href="#i_ret"><tt>ret</tt></a>',
3462 '<a href="#i_br"><tt>br</tt></a>',
3463 '<a href="#i_switch"><tt>switch</tt></a>',
3464 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3465 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3466 '<a href="#i_resume"><tt>resume</tt></a>', and
3467 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3468
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3469<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3470<h4>
3471 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3472</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3473
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3474<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3476<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3477<pre>
3478 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]3479 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3480</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3481
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3484 a value) from a function back to the caller.</p>
3485
3486<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3487 value and then causes control flow, and one that just causes control flow to
3488 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3489
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3490<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3492 return value. The type of the return value must be a
3493 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3494
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3496 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3497 value or a return value with a type that does not match its type, or if it
3498 has a void return type and contains a '<tt>ret</tt>' instruction with a
3499 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3500
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3502<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3503 the calling function's context. If the caller is a
3504 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3505 instruction after the call. If the caller was an
3506 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3507 the beginning of the "normal" destination block. If the instruction returns
3508 a value, that value shall set the call or invoke instruction's return
3509 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3510
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3511<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3512<pre>
3513 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3514 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3515 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]3516</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3517
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3518</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3519<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3520<h4>
3521 <a name="i_br">'<tt>br</tt>' Instruction</a>
3522</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3524<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3526<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3527<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3528 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3529 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3530</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3534 different basic block in the current function. There are two forms of this
3535 instruction, corresponding to a conditional branch and an unconditional
3536 branch.</p>
3537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3538<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3540 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3541 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3542 target.</p>
3543
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3545<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3546 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3547 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3548 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3551<pre>
3552Test:
3553 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3554 br i1 %cond, label %IfEqual, label %IfUnequal
3555IfEqual:
3556 <a href="#i_ret">ret</a> i32 1
3557IfUnequal:
3558 <a href="#i_ret">ret</a> i32 0
3559</pre>
3560
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3561</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3564<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3565 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3566</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3567
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3568<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3569
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3571<pre>
3572 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3573</pre>
3574
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3575<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3576<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]3577 several different places. It is a generalization of the '<tt>br</tt>'
3578 instruction, allowing a branch to occur to one of many possible
3579 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3580
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3581<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3582<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3584 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3585 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3587<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3588<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3589 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3590 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3591 transferred to the corresponding destination; otherwise, control flow is
3592 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3593
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3594<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3595<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3596 <tt>switch</tt> instruction, this instruction may be code generated in
3597 different ways. For example, it could be generated as a series of chained
3598 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3599
3600<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3601<pre>
3602 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3603 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3604 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3605
3606 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3607 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3608
3609 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3610 switch i32 %val, label %otherwise [ i32 0, label %onzero
3611 i32 1, label %onone
3612 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3613</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3614
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3615</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3616
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3617
3618<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3619<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3620 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3621</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3622
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3623<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3624
3625<h5>Syntax:</h5>
3626<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3627 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]3628</pre>
3629
3630<h5>Overview:</h5>
3631
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3632<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3633 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3634 "<tt>address</tt>". Address must be derived from a <a
3635 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3636
3637<h5>Arguments:</h5>
3638
3639<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3640 rest of the arguments indicate the full set of possible destinations that the
3641 address may point to. Blocks are allowed to occur multiple times in the
3642 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3643
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3644<p>This destination list is required so that dataflow analysis has an accurate
3645 understanding of the CFG.</p>
3646
3647<h5>Semantics:</h5>
3648
3649<p>Control transfers to the block specified in the address argument. All
3650 possible destination blocks must be listed in the label list, otherwise this
3651 instruction has undefined behavior. This implies that jumps to labels
3652 defined in other functions have undefined behavior as well.</p>
3653
3654<h5>Implementation:</h5>
3655
3656<p>This is typically implemented with a jump through a register.</p>
3657
3658<h5>Example:</h5>
3659<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3660 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3661</pre>
3662
3663</div>
3664
3665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3666<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3667<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3668 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3669</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3670
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3671<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3672
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3673<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3674<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3675 &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]3676 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3677</pre>
3678
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3679<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3680<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681 function, with the possibility of control flow transfer to either the
3682 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3683 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3684 control flow will return to the "normal" label. If the callee (or any
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3685 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3686 instruction or other exception handling mechanism, control is interrupted and
3687 continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3688
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3689<p>The '<tt>exception</tt>' label is a
3690 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3691 exception. As such, '<tt>exception</tt>' label is required to have the
3692 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosierc28f3e92011-12-09 02:00:44 +0000[diff] [blame]3693 the information about the behavior of the program after unwinding
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3694 happens, as its first non-PHI instruction. The restrictions on the
3695 "<tt>landingpad</tt>" instruction's tightly couples it to the
3696 "<tt>invoke</tt>" instruction, so that the important information contained
3697 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3698 code motion.</p>
3699
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3700<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3701<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3702
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3703<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3704 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3705 convention</a> the call should use. If none is specified, the call
3706 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3707
3708 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3709 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3710 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3711
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3712 <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]3713 function value being invoked. In most cases, this is a direct function
3714 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3715 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3716
3717 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3719
3720 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3721 signature argument types and parameter attributes. All arguments must be
3722 of <a href="#t_firstclass">first class</a> type. If the function
3723 signature indicates the function accepts a variable number of arguments,
3724 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3725
3726 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3727 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3728
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3729 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3730 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3731 handling mechanism.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3732
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3733 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3734 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3735 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3736</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3737
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3738<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3739<p>This instruction is designed to operate as a standard
3740 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3741 primary difference is that it establishes an association with a label, which
3742 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3743
3744<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3745 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3746 exception. Additionally, this is important for implementation of
3747 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3748
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749<p>For the purposes of the SSA form, the definition of the value returned by the
3750 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3751 block to the "normal" label. If the callee unwinds then no return value is
3752 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3753
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3754<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3755<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3756 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3757 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3758 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3759 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3760</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3761
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3763
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3764 <!-- _______________________________________________________________________ -->
3765
3766<h4>
3767 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3768</h4>
3769
3770<div>
3771
3772<h5>Syntax:</h5>
3773<pre>
3774 resume &lt;type&gt; &lt;value&gt;
3775</pre>
3776
3777<h5>Overview:</h5>
3778<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3779 successors.</p>
3780
3781<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3782<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3783 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3784 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
3787<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3788 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3789 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3790
3791<h5>Example:</h5>
3792<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3793 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3794</pre>
3795
3796</div>
3797
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
3799
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3800<h4>
3801 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3802</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3803
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3804<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3805
3806<h5>Syntax:</h5>
3807<pre>
3808 unreachable
3809</pre>
3810
3811<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3812<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3813 instruction is used to inform the optimizer that a particular portion of the
3814 code is not reachable. This can be used to indicate that the code after a
3815 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3816
3817<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3818<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3819
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3820</div>
3821
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3822</div>
3823
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3824<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3825<h3>
3826 <a name="binaryops">Binary Operations</a>
3827</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3829<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3830
3831<p>Binary operators are used to do most of the computation in a program. They
3832 require two operands of the same type, execute an operation on them, and
3833 produce a single value. The operands might represent multiple data, as is
3834 the case with the <a href="#t_vector">vector</a> data type. The result value
3835 has the same type as its operands.</p>
3836
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3837<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3839<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3840<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3841 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3842</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3843
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3844<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3847<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3848 &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]3849 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3850 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3851 &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]3852</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3854<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3855<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3856
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858<p>The two arguments to the '<tt>add</tt>' instruction must
3859 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3860 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3862<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3863<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3864
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3865<p>If the sum has unsigned overflow, the result returned is the mathematical
3866 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]3867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868<p>Because LLVM integers use a two's complement representation, this instruction
3869 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3870
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3871<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3872 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3873 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3874 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3875 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3878<pre>
3879 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3880</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3882</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3885<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3886 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3887</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3888
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3889<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3890
3891<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3892<pre>
3893 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3894</pre>
3895
3896<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3897<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3898
3899<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3900<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3901 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3902 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3903
3904<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3905<p>The value produced is the floating point sum of the two operands.</p>
3906
3907<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3908<pre>
3909 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3910</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3911
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3912</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3913
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3914<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3915<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3916 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3917</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3918
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3919<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3920
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3922<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3923 &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]3924 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3925 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3926 &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]3927</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3930<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3932
3933<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3934 '<tt>neg</tt>' instruction present in most other intermediate
3935 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3936
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938<p>The two arguments to the '<tt>sub</tt>' instruction must
3939 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3940 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3941
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3943<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3944
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3945<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3947 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3948
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949<p>Because LLVM integers use a two's complement representation, this instruction
3950 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3951
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3952<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3953 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3954 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3955 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3956 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3958<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3959<pre>
3960 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3961 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3964</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3966<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3967<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3968 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3969</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3970
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3971<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3972
3973<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3974<pre>
3975 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3976</pre>
3977
3978<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3979<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3980 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3981
3982<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3983 '<tt>fneg</tt>' instruction present in most other intermediate
3984 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3985
3986<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3987<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3988 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3989 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3990
3991<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3992<p>The value produced is the floating point difference of the two operands.</p>
3993
3994<h5>Example:</h5>
3995<pre>
3996 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3997 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3998</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3999
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4000</div>
4001
4002<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4003<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4004 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4005</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4006
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4007<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4009<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4011 &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]4012 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4013 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4014 &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]4015</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4017<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4018<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4019
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4020<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021<p>The two arguments to the '<tt>mul</tt>' instruction must
4022 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4023 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4024
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4025<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4026<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4027
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4028<p>If the result of the multiplication has unsigned overflow, the result
4029 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
4030 width of the result.</p>
4031
4032<p>Because LLVM integers use a two's complement representation, and the result
4033 is the same width as the operands, this instruction returns the correct
4034 result for both signed and unsigned integers. If a full product
4035 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4036 be sign-extended or zero-extended as appropriate to the width of the full
4037 product.</p>
4038
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4039<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4040 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4041 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4042 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]4043 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4044
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4045<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4046<pre>
4047 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4048</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4049
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4050</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4051
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4052<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4053<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4054 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4055</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4056
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4057<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4058
4059<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4060<pre>
4061 &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]4062</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4064<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4068<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4070 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4073<p>The value produced is the floating point product of the two operands.</p>
4074
4075<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4076<pre>
4077 &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]4078</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4079
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4080</div>
4081
4082<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4083<h4>
4084 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4085</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4086
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4087<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4088
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4089<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4090<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4091 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4092 &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]4093</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4094
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4095<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4097
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4098<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4099<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4100 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4101 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4102
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4103<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4104<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4105
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4106<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4107 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4108
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4109<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4110
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4111<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4112 <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]4113 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4114
4115
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4116<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117<pre>
4118 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4119</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4120
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4121</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4122
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4123<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4124<h4>
4125 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4126</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4127
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4128<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4130<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4131<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4132 &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]4133 &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]4134</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4135
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4136<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4137<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4138
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4139<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4140<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4141 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4142 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4143
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4144<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4145<p>The value produced is the signed integer quotient of the two operands rounded
4146 towards zero.</p>
4147
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4148<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4149 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4150
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4151<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4152 undefined behavior; this is a rare case, but can occur, for example, by doing
4153 a 32-bit division of -2147483648 by -1.</p>
4154
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]4155<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4156 <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]4157 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4158
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4159<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4160<pre>
4161 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4162</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4163
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4164</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4166<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4167<h4>
4168 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4169</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4170
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4171<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4172
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4173<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4174<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4175 &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]4176</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4177
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4178<h5>Overview:</h5>
4179<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4180
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4181<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4182<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4183 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4184 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4185
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4186<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4187<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4188
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4189<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4190<pre>
4191 &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]4192</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4193
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4194</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4195
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4196<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4197<h4>
4198 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4199</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4200
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4201<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4202
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4203<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4204<pre>
4205 &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]4206</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4207
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4208<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4209<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4210 division of its two arguments.</p>
4211
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4212<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4213<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4214 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4215 values. Both arguments must have identical types.</p>
4216
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4217<h5>Semantics:</h5>
4218<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4219 This instruction always performs an unsigned division to get the
4220 remainder.</p>
4221
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4222<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4223 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4224
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4225<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4226
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4227<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4228<pre>
4229 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4230</pre>
4231
4232</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4233
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4235<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4236 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4237</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4238
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4239<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4241<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4242<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4243 &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]4244</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4245
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4246<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4247<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4248 division of its two operands. This instruction can also take
4249 <a href="#t_vector">vector</a> versions of the values in which case the
4250 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]4251
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4252<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4253<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4254 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4255 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4256
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4257<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4258<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4259 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4260 <i>modulo</i> operator (where the result is either zero or has the same sign
4261 as the divisor, <tt>op2</tt>) of a value.
4262 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4263 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4264 Math Forum</a>. For a table of how this is implemented in various languages,
4265 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4266 Wikipedia: modulo operation</a>.</p>
4267
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4268<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4269 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4270
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4271<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4272 Overflow also leads to undefined behavior; this is a rare case, but can
4273 occur, for example, by taking the remainder of a 32-bit division of
4274 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4275 lets srem be implemented using instructions that return both the result of
4276 the division and the remainder.)</p>
4277
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4278<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4279<pre>
4280 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4281</pre>
4282
4283</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4284
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4285<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4286<h4>
4287 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4288</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4289
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4290<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4291
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4292<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4293<pre>
4294 &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]4295</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4296
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4297<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4298<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4299 its two operands.</p>
4300
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4301<h5>Arguments:</h5>
4302<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4304 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4305
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4306<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307<p>This instruction returns the <i>remainder</i> of a division. The remainder
4308 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4309
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4310<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4311<pre>
4312 &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]4313</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4314
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4315</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4316
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4317</div>
4318
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4319<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4320<h3>
4321 <a name="bitwiseops">Bitwise Binary Operations</a>
4322</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4323
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4324<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4325
4326<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4327 program. They are generally very efficient instructions and can commonly be
4328 strength reduced from other instructions. They require two operands of the
4329 same type, execute an operation on them, and produce a single value. The
4330 resulting value is the same type as its operands.</p>
4331
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4332<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4333<h4>
4334 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4335</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4337<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4339<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4341 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4342 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4343 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4344 &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]4345</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4346
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4347<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4348<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4349 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4350
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4351<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4352<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4353 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4354 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4355
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4356<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4357<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4358 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4359 is (statically or dynamically) negative or equal to or larger than the number
4360 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4361 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4362 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4363
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4364<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4365 <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]4366 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4367 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4368 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4369 they would if the shift were expressed as a mul instruction with the same
4370 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4371
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4372<h5>Example:</h5>
4373<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4374 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4375 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4376 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4377 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4378 &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]4379</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4380
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4381</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4382
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4383<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4384<h4>
4385 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4386</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4387
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4388<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4389
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4390<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4391<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4392 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4393 &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]4394</pre>
4395
4396<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4397<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4398 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4399
4400<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4401<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4402 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4403 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4404
4405<h5>Semantics:</h5>
4406<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4407 significant bits of the result will be filled with zero bits after the shift.
4408 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4409 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4410 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4411 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4412
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4413<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4414 <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]4415 shifted out are non-zero.</p>
4416
4417
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4418<h5>Example:</h5>
4419<pre>
4420 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4421 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4422 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4423 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4424 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4425 &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]4426</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4427
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4428</div>
4429
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4430<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4431<h4>
4432 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4433</h4>
4434
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4435<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4436
4437<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4438<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4439 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4440 &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]4441</pre>
4442
4443<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4445 operand shifted to the right a specified number of bits with sign
4446 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4447
4448<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4449<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4450 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4451 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4452
4453<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454<p>This instruction always performs an arithmetic shift right operation, The
4455 most significant bits of the result will be filled with the sign bit
4456 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4457 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4458 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4459 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4460
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4461<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4462 <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]4463 shifted out are non-zero.</p>
4464
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4465<h5>Example:</h5>
4466<pre>
4467 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4468 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4469 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4470 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4471 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4472 &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]4473</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4474
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4475</div>
4476
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4477<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4478<h4>
4479 <a name="i_and">'<tt>and</tt>' Instruction</a>
4480</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4481
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4482<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4483
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4484<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4485<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4486 &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]4487</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4488
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4489<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4491 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4492
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4493<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4494<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4495 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4496 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4498<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4499<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4500
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4501<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4502 <tbody>
4503 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4504 <th>In0</th>
4505 <th>In1</th>
4506 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4507 </tr>
4508 <tr>
4509 <td>0</td>
4510 <td>0</td>
4511 <td>0</td>
4512 </tr>
4513 <tr>
4514 <td>0</td>
4515 <td>1</td>
4516 <td>0</td>
4517 </tr>
4518 <tr>
4519 <td>1</td>
4520 <td>0</td>
4521 <td>0</td>
4522 </tr>
4523 <tr>
4524 <td>1</td>
4525 <td>1</td>
4526 <td>1</td>
4527 </tr>
4528 </tbody>
4529</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4530
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4531<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4532<pre>
4533 &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]4534 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4535 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4536</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4537</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4538<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4539<h4>
4540 <a name="i_or">'<tt>or</tt>' Instruction</a>
4541</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4542
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4543<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4544
4545<h5>Syntax:</h5>
4546<pre>
4547 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4548</pre>
4549
4550<h5>Overview:</h5>
4551<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4552 two operands.</p>
4553
4554<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4555<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4556 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4557 values. Both arguments must have identical types.</p>
4558
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4559<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4560<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4561
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4562<table border="1" cellspacing="0" cellpadding="4">
4563 <tbody>
4564 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4565 <th>In0</th>
4566 <th>In1</th>
4567 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4568 </tr>
4569 <tr>
4570 <td>0</td>
4571 <td>0</td>
4572 <td>0</td>
4573 </tr>
4574 <tr>
4575 <td>0</td>
4576 <td>1</td>
4577 <td>1</td>
4578 </tr>
4579 <tr>
4580 <td>1</td>
4581 <td>0</td>
4582 <td>1</td>
4583 </tr>
4584 <tr>
4585 <td>1</td>
4586 <td>1</td>
4587 <td>1</td>
4588 </tr>
4589 </tbody>
4590</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4592<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4593<pre>
4594 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4595 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4596 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4597</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4598
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4599</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4600
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4601<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4602<h4>
4603 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4604</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4605
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4606<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4607
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4608<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4609<pre>
4610 &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]4611</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4612
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4613<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4614<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4615 its two operands. The <tt>xor</tt> is used to implement the "one's
4616 complement" operation, which is the "~" operator in C.</p>
4617
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4618<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4619<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4621 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4622
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4623<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4624<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4625
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4626<table border="1" cellspacing="0" cellpadding="4">
4627 <tbody>
4628 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4629 <th>In0</th>
4630 <th>In1</th>
4631 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4632 </tr>
4633 <tr>
4634 <td>0</td>
4635 <td>0</td>
4636 <td>0</td>
4637 </tr>
4638 <tr>
4639 <td>0</td>
4640 <td>1</td>
4641 <td>1</td>
4642 </tr>
4643 <tr>
4644 <td>1</td>
4645 <td>0</td>
4646 <td>1</td>
4647 </tr>
4648 <tr>
4649 <td>1</td>
4650 <td>1</td>
4651 <td>0</td>
4652 </tr>
4653 </tbody>
4654</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4655
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4656<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4657<pre>
4658 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4659 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4660 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4661 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4662</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4664</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4665
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4666</div>
4667
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4668<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4669<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4670 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4671</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4672
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4673<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4674
4675<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4676 target-independent manner. These instructions cover the element-access and
4677 vector-specific operations needed to process vectors effectively. While LLVM
4678 does directly support these vector operations, many sophisticated algorithms
4679 will want to use target-specific intrinsics to take full advantage of a
4680 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4681
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4682<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4683<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4684 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4685</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4686
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4687<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4688
4689<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4690<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4691 &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]4692</pre>
4693
4694<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4695<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4696 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4697
4698
4699<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4701 of <a href="#t_vector">vector</a> type. The second operand is an index
4702 indicating the position from which to extract the element. The index may be
4703 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4704
4705<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706<p>The result is a scalar of the same type as the element type of
4707 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4708 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4709 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4710
4711<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4712<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4713 &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]4714</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4715
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4716</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4717
4718<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4719<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4720 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4721</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4722
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4723<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4724
4725<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4726<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4727 &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]4728</pre>
4729
4730<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4731<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4732 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4733
4734<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4735<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4736 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4737 whose type must equal the element type of the first operand. The third
4738 operand is an index indicating the position at which to insert the value.
4739 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4740
4741<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4742<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4743 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4744 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4745 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4746
4747<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4748<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4749 &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]4750</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4751
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4755<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4756 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4757</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4758
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4759<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4760
4761<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4762<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4763 &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]4764</pre>
4765
4766<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4768 from two input vectors, returning a vector with the same element type as the
4769 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4770
4771<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4772<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsbe3d3a62012-06-14 14:58:28 +0000[diff] [blame]4773 with the same type. The third argument is a shuffle mask whose
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774 element type is always 'i32'. The result of the instruction is a vector
4775 whose length is the same as the shuffle mask and whose element type is the
4776 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4777
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4778<p>The shuffle mask operand is required to be a constant vector with either
4779 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4780
4781<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4782<p>The elements of the two input vectors are numbered from left to right across
4783 both of the vectors. The shuffle mask operand specifies, for each element of
4784 the result vector, which element of the two input vectors the result element
4785 gets. The element selector may be undef (meaning "don't care") and the
4786 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4787
4788<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4789<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4790 &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]4791 &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]4792 &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]4793 &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]4794 &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]4795 &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]4796 &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]4797 &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]4798</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4799
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4801
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4802</div>
4803
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4804<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4805<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4806 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4807</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4808
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4809<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4810
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4811<p>LLVM supports several instructions for working with
4812 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4813
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4814<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4815<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4816 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4817</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4818
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4819<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4820
4821<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4822<pre>
4823 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4824</pre>
4825
4826<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4827<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4828 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4829
4830<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4831<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4832 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4833 <a href="#t_array">array</a> type. The operands are constant indices to
4834 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4835 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4836 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4837 <ul>
4838 <li>Since the value being indexed is not a pointer, the first index is
4839 omitted and assumed to be zero.</li>
4840 <li>At least one index must be specified.</li>
4841 <li>Not only struct indices but also array indices must be in
4842 bounds.</li>
4843 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4844
4845<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4846<p>The result is the value at the position in the aggregate specified by the
4847 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4848
4849<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4850<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4851 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4852</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4853
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4854</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4855
4856<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4857<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4858 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4859</h4>
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
4863<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4864<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4865 &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]4866</pre>
4867
4868<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4869<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4870 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4871
4872<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4873<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4874 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4875 <a href="#t_array">array</a> type. The second operand is a first-class
4876 value to insert. The following operands are constant indices indicating
4877 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]4878 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4879 value to insert must have the same type as the value identified by the
4880 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4881
4882<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4884 that of <tt>val</tt> except that the value at the position specified by the
4885 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4886
4887<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4888<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4889 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4890 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4891 %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]4892</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4893
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4894</div>
4895
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4896</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4897
4898<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4899<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4900 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4901</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4902
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4903<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4904
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4905<p>A key design point of an SSA-based representation is how it represents
4906 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4907 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4908 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4910<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4911<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4912 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4913</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4914
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4915<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4916
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4917<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4918<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4919 &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]4920</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4922<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4923<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924 currently executing function, to be automatically released when this function
4925 returns to its caller. The object is always allocated in the generic address
4926 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4927
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4928<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4929<p>The '<tt>alloca</tt>' instruction
4930 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4931 runtime stack, returning a pointer of the appropriate type to the program.
4932 If "NumElements" is specified, it is the number of elements allocated,
4933 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4934 specified, the value result of the allocation is guaranteed to be aligned to
4935 at least that boundary. If not specified, or if zero, the target can choose
4936 to align the allocation on any convenient boundary compatible with the
4937 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4938
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4939<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4940
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4941<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4942<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4943 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4944 memory is automatically released when the function returns. The
4945 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4946 variables that must have an address available. When the function returns
4947 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]4948 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]4949 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4950 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewyckyf70a2bd2012-03-18 09:35:50 +0000[diff] [blame]4951 not specified.</p>
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]4952
4953<p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4954
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4955<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4956<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4957 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4958 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4959 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4960 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4961</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4962
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4963</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4964
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4965<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4966<h4>
4967 <a name="i_load">'<tt>load</tt>' Instruction</a>
4968</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4969
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4970<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4972<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4973<pre>
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]4974 &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]4975 &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]4976 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4977</pre>
4978
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4979<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4980<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4981
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4982<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4983<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4984 from which to load. The pointer must point to
4985 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4986 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4987 number or order of execution of this <tt>load</tt> with other <a
4988 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4989
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4990<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4991 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4992 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4993 not valid on <code>load</code> instructions. Atomic loads produce <a
4994 href="#memorymodel">defined</a> results when they may see multiple atomic
4995 stores. The type of the pointee must be an integer type whose bit width
4996 is a power of two greater than or equal to eight and less than or equal
4997 to a target-specific size limit. <code>align</code> must be explicitly
4998 specified on atomic loads, and the load has undefined behavior if the
4999 alignment is not set to a value which is at least the size in bytes of
5000 the pointee. <code>!nontemporal</code> does not have any defined semantics
5001 for atomic loads.</p>
5002
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5003<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004 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]5005 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5006 alignment for the target. It is the responsibility of the code emitter to
5007 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5008 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5009 produce less efficient code. An alignment of 1 is always safe.</p>
5010
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5011<p>The optional <tt>!nontemporal</tt> metadata must reference a single
5012 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5013 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]5014 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
5015 and code generator that this load is not expected to be reused in the cache.
5016 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5017 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5018
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]5019<p>The optional <tt>!invariant.load</tt> metadata must reference a single
5020 metatadata name &lt;index&gt; corresponding to a metadata node with no
5021 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
5022 instruction tells the optimizer and code generator that this load address
5023 points to memory which does not change value during program execution.
5024 The optimizer may then move this load around, for example, by hoisting it
5025 out of loops using loop invariant code motion.</p>
5026
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5027<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5028<p>The location of memory pointed to is loaded. If the value being loaded is of
5029 scalar type then the number of bytes read does not exceed the minimum number
5030 of bytes needed to hold all bits of the type. For example, loading an
5031 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5032 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5033 is undefined if the value was not originally written using a store of the
5034 same type.</p>
5035
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5036<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5037<pre>
5038 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5039 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5040 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5041</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5042
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5043</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5045<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5046<h4>
5047 <a name="i_store">'<tt>store</tt>' Instruction</a>
5048</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5049
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5050<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5052<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5053<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5054 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>
5055 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]5056</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5057
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5058<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5059<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5060
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5061<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5063 and an address at which to store it. The type of the
5064 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5065 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]5066 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5067 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5068 order of execution of this <tt>store</tt> with other <a
5069 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5070
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]5071<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5072 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5073 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5074 valid on <code>store</code> instructions. Atomic loads produce <a
5075 href="#memorymodel">defined</a> results when they may see multiple atomic
5076 stores. The type of the pointee must be an integer type whose bit width
5077 is a power of two greater than or equal to eight and less than or equal
5078 to a target-specific size limit. <code>align</code> must be explicitly
5079 specified on atomic stores, and the store has undefined behavior if the
5080 alignment is not set to a value which is at least the size in bytes of
5081 the pointee. <code>!nontemporal</code> does not have any defined semantics
5082 for atomic stores.</p>
5083
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084<p>The optional constant "align" argument specifies the alignment of the
5085 operation (that is, the alignment of the memory address). A value of 0 or an
5086 omitted "align" argument means that the operation has the preferential
5087 alignment for the target. It is the responsibility of the code emitter to
5088 ensure that the alignment information is correct. Overestimating the
5089 alignment results in an undefined behavior. Underestimating the alignment may
5090 produce less efficient code. An alignment of 1 is always safe.</p>
5091
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5092<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5093 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5094 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5095 instruction tells the optimizer and code generator that this load is
5096 not expected to be reused in the cache. The code generator may
5097 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5098 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5099
5100
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5101<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5102<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5103 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5104 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5105 does not exceed the minimum number of bytes needed to hold all bits of the
5106 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5107 writing a value of a type like <tt>i20</tt> with a size that is not an
5108 integral number of bytes, it is unspecified what happens to the extra bits
5109 that do not belong to the type, but they will typically be overwritten.</p>
5110
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5111<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5112<pre>
5113 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]5114 store i32 3, i32* %ptr <i>; yields {void}</i>
5115 %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]5116</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5117
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5118</div>
5119
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5120<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5121<h4>
5122<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5123</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5124
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5125<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5126
5127<h5>Syntax:</h5>
5128<pre>
5129 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5130</pre>
5131
5132<h5>Overview:</h5>
5133<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5134between operations.</p>
5135
5136<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5137href="#ordering">ordering</a> argument which defines what
5138<i>synchronizes-with</i> edges they add. They can only be given
5139<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5140<code>seq_cst</code> orderings.</p>
5141
5142<h5>Semantics:</h5>
5143<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5144semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5145<code>acquire</code> ordering semantics if and only if there exist atomic
5146operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5147<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5148<var>X</var> modifies <var>M</var> (either directly or through some side effect
5149of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5150<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5151<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5152than an explicit <code>fence</code>, one (but not both) of the atomic operations
5153<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5154<code>acquire</code> (resp.) ordering constraint and still
5155<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5156<i>happens-before</i> edge.</p>
5157
5158<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5159having both <code>acquire</code> and <code>release</code> semantics specified
5160above, participates in the global program order of other <code>seq_cst</code>
5161operations and/or fences.</p>
5162
5163<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5164specifies that the fence only synchronizes with other fences in the same
5165thread. (This is useful for interacting with signal handlers.)</p>
5166
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5167<h5>Example:</h5>
5168<pre>
5169 fence acquire <i>; yields {void}</i>
5170 fence singlethread seq_cst <i>; yields {void}</i>
5171</pre>
5172
5173</div>
5174
5175<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5176<h4>
5177<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5178</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5179
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5180<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5181
5182<h5>Syntax:</h5>
5183<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5184 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]5185</pre>
5186
5187<h5>Overview:</h5>
5188<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5189It loads a value in memory and compares it to a given value. If they are
5190equal, it stores a new value into the memory.</p>
5191
5192<h5>Arguments:</h5>
5193<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5194address to operate on, a value to compare to the value currently be at that
5195address, and a new value to place at that address if the compared values are
5196equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5197bit width is a power of two greater than or equal to eight and less than
5198or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5199'<var>&lt;new&gt;</var>' must have the same type, and the type of
5200'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5201<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5202optimizer is not allowed to modify the number or order of execution
5203of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5204operations</a>.</p>
5205
5206<!-- FIXME: Extend allowed types. -->
5207
5208<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5209<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5210
5211<p>The optional "<code>singlethread</code>" argument declares that the
5212<code>cmpxchg</code> is only atomic with respect to code (usually signal
5213handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5214cmpxchg is atomic with respect to all other code in the system.</p>
5215
5216<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5217the size in memory of the operand.
5218
5219<h5>Semantics:</h5>
5220<p>The contents of memory at the location specified by the
5221'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5222'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5223'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5224is returned.
5225
5226<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5227purpose of identifying <a href="#release_sequence">release sequences</a>. A
5228failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5229parameter determined by dropping any <code>release</code> part of the
5230<code>cmpxchg</code>'s ordering.</p>
5231
5232<!--
5233FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5234optimization work on ARM.)
5235
5236FIXME: Is a weaker ordering constraint on failure helpful in practice?
5237-->
5238
5239<h5>Example:</h5>
5240<pre>
5241entry:
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5242 %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]5243 <a href="#i_br">br</a> label %loop
5244
5245loop:
5246 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5247 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5248 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5249 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5250 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5251
5252done:
5253 ...
5254</pre>
5255
5256</div>
5257
5258<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5259<h4>
5260<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5261</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5262
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5263<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5264
5265<h5>Syntax:</h5>
5266<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]5267 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]5268</pre>
5269
5270<h5>Overview:</h5>
5271<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5272
5273<h5>Arguments:</h5>
5274<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5275operation to apply, an address whose value to modify, an argument to the
5276operation. The operation must be one of the following keywords:</p>
5277<ul>
5278 <li>xchg</li>
5279 <li>add</li>
5280 <li>sub</li>
5281 <li>and</li>
5282 <li>nand</li>
5283 <li>or</li>
5284 <li>xor</li>
5285 <li>max</li>
5286 <li>min</li>
5287 <li>umax</li>
5288 <li>umin</li>
5289</ul>
5290
5291<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5292bit width is a power of two greater than or equal to eight and less than
5293or equal to a target-specific size limit. The type of the
5294'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5295If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5296optimizer is not allowed to modify the number or order of execution of this
5297<code>atomicrmw</code> with other <a href="#volatile">volatile
5298 operations</a>.</p>
5299
5300<!-- FIXME: Extend allowed types. -->
5301
5302<h5>Semantics:</h5>
5303<p>The contents of memory at the location specified by the
5304'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5305back. The original value at the location is returned. The modification is
5306specified by the <var>operation</var> argument:</p>
5307
5308<ul>
5309 <li>xchg: <code>*ptr = val</code></li>
5310 <li>add: <code>*ptr = *ptr + val</code></li>
5311 <li>sub: <code>*ptr = *ptr - val</code></li>
5312 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5313 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5314 <li>or: <code>*ptr = *ptr | val</code></li>
5315 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5316 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5317 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5318 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5319 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5320</ul>
5321
5322<h5>Example:</h5>
5323<pre>
5324 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5325</pre>
5326
5327</div>
5328
5329<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5330<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5331 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5332</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5333
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5334<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5335
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5336<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5337<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5338 &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]5339 &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]5340 &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]5341</pre>
5342
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5343<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5344<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5345 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5346 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5347
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5348<h5>Arguments:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5349<p>The first argument is always a pointer or a vector of pointers,
5350 and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5351 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5352 elements of the aggregate object are indexed. The interpretation of each
5353 index is dependent on the type being indexed into. The first index always
5354 indexes the pointer value given as the first argument, the second index
5355 indexes a value of the type pointed to (not necessarily the value directly
5356 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5357 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5358 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5359 can never be pointers, since that would require loading the pointer before
5360 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5361
5362<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]5363 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5364 integer <b>constants</b> are allowed. When indexing into an array, pointer
5365 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]5366 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5368<p>For example, let's consider a C code fragment and how it gets compiled to
5369 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5370
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5371<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5372struct RT {
5373 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5374 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5375 char C;
5376};
5377struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5378 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5379 double Y;
5380 struct RT Z;
5381};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5382
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5383int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5384 return &amp;s[1].Z.B[5][13];
5385}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5386</pre>
5387
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5388<p>The LLVM code generated by Clang is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5389
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5390<pre class="doc_code">
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5391%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5392%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5393
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5394define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5395entry:
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5396 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5397 ret i32* %arrayidx
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5398}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5399</pre>
5400
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5401<h5>Semantics:</h5>
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5402<p>In the example above, the first index is indexing into the
5403 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5404 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5405 structure. The second index indexes into the third element of the structure,
5406 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5407 type, another structure. The third index indexes into the second element of
5408 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5409 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5410 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5411 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5412
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5413<p>Note that it is perfectly legal to index partially through a structure,
5414 returning a pointer to an inner element. Because of this, the LLVM code for
5415 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5416
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5417<pre class="doc_code">
5418define i32* @foo(%struct.ST* %s) {
5419 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5420 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5421 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5422 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5423 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5424 ret i32* %t5
5425}
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5426</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5427
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5428<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]5429 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5430 base pointer is not an <i>in bounds</i> address of an allocated object,
5431 or if any of the addresses that would be formed by successive addition of
5432 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5433 precise signed arithmetic are not an <i>in bounds</i> address of that
5434 allocated object. The <i>in bounds</i> addresses for an allocated object
5435 are all the addresses that point into the object, plus the address one
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5436 byte past the end.
5437 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5438 applies to each of the computations element-wise. </p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5439
5440<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]5441 the base address with silently-wrapping two's complement arithmetic. If the
5442 offsets have a different width from the pointer, they are sign-extended or
5443 truncated to the width of the pointer. The result value of the
5444 <tt>getelementptr</tt> may be outside the object pointed to by the base
5445 pointer. The result value may not necessarily be used to access memory
5446 though, even if it happens to point into allocated storage. See the
5447 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5448 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5449
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5450<p>The getelementptr instruction is often confusing. For some more insight into
5451 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5452
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5453<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5454<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5455 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5456 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5457 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5458 %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]5459 <i>; yields i8*:eptr</i>
5460 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5461 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5462 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5463</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5464
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5465<p>In cases where the pointer argument is a vector of pointers, only a
5466 single index may be used, and the number of vector elements has to be
5467 the same. For example: </p>
5468<pre class="doc_code">
5469 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5470</pre>
5471
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5472</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5473
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5474</div>
5475
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5476<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5477<h3>
5478 <a name="convertops">Conversion Operations</a>
5479</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5480
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5481<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5482
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5483<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5484 which all take a single operand and a type. They perform various bit
5485 conversions on the operand.</p>
5486
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5487<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5488<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5489 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5490</h4>
5491
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5492<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5493
5494<h5>Syntax:</h5>
5495<pre>
5496 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5501 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5502
5503<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5504<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5505 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5506 of the same number of integers.
5507 The bit size of the <tt>value</tt> must be larger than
5508 the bit size of the destination type, <tt>ty2</tt>.
5509 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5510
5511<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5512<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5513 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5514 source size must be larger than the destination size, <tt>trunc</tt> cannot
5515 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5516
5517<h5>Example:</h5>
5518<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5519 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5520 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5521 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5522 %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]5523</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5524
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5525</div>
5526
5527<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5528<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5529 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5530</h4>
5531
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5532<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5533
5534<h5>Syntax:</h5>
5535<pre>
5536 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5537</pre>
5538
5539<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5540<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5541 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5542
5543
5544<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5545<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5546 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5547 of the same number of integers.
5548 The bit size of the <tt>value</tt> must be smaller than
5549 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5550 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5551
5552<h5>Semantics:</h5>
5553<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]5554 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5555
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5556<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]5557
5558<h5>Example:</h5>
5559<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5560 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5561 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5562 %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]5563</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5564
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5565</div>
5566
5567<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5568<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5569 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5570</h4>
5571
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5572<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5573
5574<h5>Syntax:</h5>
5575<pre>
5576 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5577</pre>
5578
5579<h5>Overview:</h5>
5580<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5581
5582<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5583<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5584 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5585 of the same number of integers.
5586 The bit size of the <tt>value</tt> must be smaller than
5587 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5588 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5589
5590<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5591<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5592 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5593 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5594
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5595<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]5596
5597<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5598<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5599 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5600 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5601 %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]5602</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5603
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5604</div>
5605
5606<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5607<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5608 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5609</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5610
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5611<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5612
5613<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5614<pre>
5615 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5616</pre>
5617
5618<h5>Overview:</h5>
5619<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5620 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5621
5622<h5>Arguments:</h5>
5623<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5624 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5625 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]5626 <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]5627 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5628
5629<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5630<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5631 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5632 <a href="#t_floating">floating point</a> type. If the value cannot fit
5633 within the destination type, <tt>ty2</tt>, then the results are
5634 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5635
5636<h5>Example:</h5>
5637<pre>
5638 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5639 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5640</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5641
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5642</div>
5643
5644<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5645<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5646 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5647</h4>
5648
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5649<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5650
5651<h5>Syntax:</h5>
5652<pre>
5653 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5654</pre>
5655
5656<h5>Overview:</h5>
5657<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]5658 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5659
5660<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5661<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5662 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5663 a <a href="#t_floating">floating point</a> type to cast it to. The source
5664 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5665
5666<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5667<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5668 <a href="#t_floating">floating point</a> type to a larger
5669 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5670 used to make a <i>no-op cast</i> because it always changes bits. Use
5671 <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]5672
5673<h5>Example:</h5>
5674<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5675 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5676 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5677</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5678
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5679</div>
5680
5681<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5682<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5683 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5684</h4>
5685
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5686<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5687
5688<h5>Syntax:</h5>
5689<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5690 &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]5691</pre>
5692
5693<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5694<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5695 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5696
5697<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5698<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5699 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5700 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5701 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5702 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5703
5704<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5705<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5707 towards zero) unsigned integer value. If the value cannot fit
5708 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5709
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5710<h5>Example:</h5>
5711<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5712 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5713 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5714 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5715</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5716
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5717</div>
5718
5719<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5720<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5721 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5722</h4>
5723
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5724<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5725
5726<h5>Syntax:</h5>
5727<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5728 &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]5729</pre>
5730
5731<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5732<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5733 <a href="#t_floating">floating point</a> <tt>value</tt> to
5734 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5735
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5736<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5737<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5738 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5739 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5740 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5741 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5742
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5743<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5744<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5745 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5746 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5747 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5748
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5749<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5750<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5751 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5752 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5753 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5754</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5755
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5756</div>
5757
5758<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5759<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5760 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5761</h4>
5762
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5763<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5764
5765<h5>Syntax:</h5>
5766<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5767 &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]5768</pre>
5769
5770<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5771<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5772 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5773
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5774<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5775<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]5776 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5777 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5778 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5779 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5780
5781<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5782<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5783 integer quantity and converts it to the corresponding floating point
5784 value. If the value cannot fit in the floating point value, the results are
5785 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5786
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5787<h5>Example:</h5>
5788<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5789 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5790 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5791</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5793</div>
5794
5795<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5796<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5797 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5798</h4>
5799
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5800<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5801
5802<h5>Syntax:</h5>
5803<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5804 &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]5805</pre>
5806
5807<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5809 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5810
5811<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5812<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]5813 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5814 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5815 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5816 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5817
5818<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5820 quantity and converts it to the corresponding floating point value. If the
5821 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5822
5823<h5>Example:</h5>
5824<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5825 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5826 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5828
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5829</div>
5830
5831<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5832<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5833 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5834</h4>
5835
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5836<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5837
5838<h5>Syntax:</h5>
5839<pre>
5840 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5841</pre>
5842
5843<h5>Overview:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5844<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5845 pointers <tt>value</tt> to
5846 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5847
5848<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5850 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5851 pointers, and a type to cast it to
5852 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5853 of integers type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5854
5855<h5>Semantics:</h5>
5856<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5857 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5858 truncating or zero extending that value to the size of the integer type. If
5859 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5860 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5861 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5862 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5863
5864<h5>Example:</h5>
5865<pre>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5866 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5867 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5868 %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]5869</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5870
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5871</div>
5872
5873<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5874<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5875 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5876</h4>
5877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5878<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5879
5880<h5>Syntax:</h5>
5881<pre>
5882 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5887 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5890<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5891 value to cast, and a type to cast it to, which must be a
5892 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5893
5894<h5>Semantics:</h5>
5895<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5896 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5897 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5898 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5899 than the size of a pointer then a zero extension is done. If they are the
5900 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5901
5902<h5>Example:</h5>
5903<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5904 %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]5905 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5906 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5907 %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]5908</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5909
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5910</div>
5911
5912<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5913<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5914 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5915</h4>
5916
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5917<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5918
5919<h5>Syntax:</h5>
5920<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5921 &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]5922</pre>
5923
5924<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5925<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5926 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5927
5928<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5930 non-aggregate first class value, and a type to cast it to, which must also be
5931 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5932 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5933 identical. If the source type is a pointer, the destination type must also be
5934 a pointer. This instruction supports bitwise conversion of vectors to
5935 integers and to vectors of other types (as long as they have the same
5936 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5937
5938<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5939<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5940 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5941 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5942 stored to memory and read back as type <tt>ty2</tt>.
5943 Pointer (or vector of pointers) types may only be converted to other pointer
5944 (or vector of pointers) types with this instruction. To convert
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5945 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5946 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5947
5948<h5>Example:</h5>
5949<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5950 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5951 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5952 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5953 %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]5954</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5956</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5958</div>
5959
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5960<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5961<h3>
5962 <a name="otherops">Other Operations</a>
5963</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5965<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5966
5967<p>The instructions in this category are the "miscellaneous" instructions, which
5968 defy better classification.</p>
5969
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5970<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5971<h4>
5972 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5973</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5974
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5975<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5976
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5977<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5978<pre>
5979 &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]5980</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5982<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5984 boolean values based on comparison of its two integer, integer vector,
5985 pointer, or pointer vector operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5986
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5987<h5>Arguments:</h5>
5988<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5989 the condition code indicating the kind of comparison to perform. It is not a
5990 value, just a keyword. The possible condition code are:</p>
5991
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5992<ol>
5993 <li><tt>eq</tt>: equal</li>
5994 <li><tt>ne</tt>: not equal </li>
5995 <li><tt>ugt</tt>: unsigned greater than</li>
5996 <li><tt>uge</tt>: unsigned greater or equal</li>
5997 <li><tt>ult</tt>: unsigned less than</li>
5998 <li><tt>ule</tt>: unsigned less or equal</li>
5999 <li><tt>sgt</tt>: signed greater than</li>
6000 <li><tt>sge</tt>: signed greater or equal</li>
6001 <li><tt>slt</tt>: signed less than</li>
6002 <li><tt>sle</tt>: signed less or equal</li>
6003</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]6005<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6006 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
6007 typed. They must also be identical types.</p>
6008
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6009<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6010<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
6011 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6012 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]6013 result, as follows:</p>
6014
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6015<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6016 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017 <tt>false</tt> otherwise. No sign interpretation is necessary or
6018 performed.</li>
6019
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6020 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6021 <tt>false</tt> otherwise. No sign interpretation is necessary or
6022 performed.</li>
6023
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6024 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6025 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6026
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6027 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6029 to <tt>op2</tt>.</li>
6030
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6031 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6032 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6033
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6034 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6035 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6036
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6037 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6039
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6040 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6041 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6042 to <tt>op2</tt>.</li>
6043
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6044 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6045 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6046
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6047 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6048 <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]6049</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6050
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6051<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6052 values are compared as if they were integers.</p>
6053
6054<p>If the operands are integer vectors, then they are compared element by
6055 element. The result is an <tt>i1</tt> vector with the same number of elements
6056 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6057
6058<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6059<pre>
6060 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6061 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6062 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6063 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6064 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6065 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6066</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6067
6068<p>Note that the code generator does not yet support vector types with
6069 the <tt>icmp</tt> instruction.</p>
6070
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6071</div>
6072
6073<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6074<h4>
6075 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6076</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6077
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6078<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6079
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6080<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6081<pre>
6082 &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]6083</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6084
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6085<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6086<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6087 values based on comparison of its operands.</p>
6088
6089<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]6090(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6091
6092<p>If the operands are floating point vectors, then the result type is a vector
6093 of boolean with the same number of elements as the operands being
6094 compared.</p>
6095
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6096<h5>Arguments:</h5>
6097<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6098 the condition code indicating the kind of comparison to perform. It is not a
6099 value, just a keyword. The possible condition code are:</p>
6100
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6101<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6102 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6103 <li><tt>oeq</tt>: ordered and equal</li>
6104 <li><tt>ogt</tt>: ordered and greater than </li>
6105 <li><tt>oge</tt>: ordered and greater than or equal</li>
6106 <li><tt>olt</tt>: ordered and less than </li>
6107 <li><tt>ole</tt>: ordered and less than or equal</li>
6108 <li><tt>one</tt>: ordered and not equal</li>
6109 <li><tt>ord</tt>: ordered (no nans)</li>
6110 <li><tt>ueq</tt>: unordered or equal</li>
6111 <li><tt>ugt</tt>: unordered or greater than </li>
6112 <li><tt>uge</tt>: unordered or greater than or equal</li>
6113 <li><tt>ult</tt>: unordered or less than </li>
6114 <li><tt>ule</tt>: unordered or less than or equal</li>
6115 <li><tt>une</tt>: unordered or not equal</li>
6116 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6117 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6118</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6119
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6120<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6121 <i>unordered</i> means that either operand may be a QNAN.</p>
6122
6123<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6124 a <a href="#t_floating">floating point</a> type or
6125 a <a href="#t_vector">vector</a> of floating point type. They must have
6126 identical types.</p>
6127
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6128<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]6129<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6130 according to the condition code given as <tt>cond</tt>. If the operands are
6131 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6132 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6133 follows:</p>
6134
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6135<ol>
6136 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6137
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6138 <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]6139 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6140
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6141 <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]6142 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6143
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6144 <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]6145 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6146
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6147 <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]6148 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6149
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6150 <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]6151 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6152
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6153 <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]6154 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6155
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6156 <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]6157
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6158 <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]6159 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6160
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6161 <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]6162 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6163
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6164 <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]6165 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6166
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6167 <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]6168 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6169
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6170 <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]6171 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6172
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6173 <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]6174 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6175
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6176 <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]6177
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6178 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6179</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6180
6181<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6182<pre>
6183 &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]6184 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6185 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6186 &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]6187</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6188
6189<p>Note that the code generator does not yet support vector types with
6190 the <tt>fcmp</tt> instruction.</p>
6191
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6192</div>
6193
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6194<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6195<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6196 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6197</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6198
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6199<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6200
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6201<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6202<pre>
6203 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6204</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6205
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6206<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6207<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6208 SSA graph representing the function.</p>
6209
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6210<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6211<p>The type of the incoming values is specified with the first type field. After
6212 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6213 one pair for each predecessor basic block of the current block. Only values
6214 of <a href="#t_firstclass">first class</a> type may be used as the value
6215 arguments to the PHI node. Only labels may be used as the label
6216 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6217
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6218<p>There must be no non-phi instructions between the start of a basic block and
6219 the PHI instructions: i.e. PHI instructions must be first in a basic
6220 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6221
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6222<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6223 occur on the edge from the corresponding predecessor block to the current
6224 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6225 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]6226
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6227<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6228<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6229 specified by the pair corresponding to the predecessor basic block that
6230 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6231
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6232<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6233<pre>
6234Loop: ; Infinite loop that counts from 0 on up...
6235 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6236 %nextindvar = add i32 %indvar, 1
6237 br label %Loop
6238</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6240</div>
6241
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6242<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6243<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6244 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6245</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6246
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6247<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6248
6249<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6250<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6251 &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>
6252
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6253 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6254</pre>
6255
6256<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6258 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6259
6260
6261<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6262<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6263 values indicating the condition, and two values of the
6264 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6265 vectors and the condition is a scalar, then entire vectors are selected, not
6266 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6267
6268<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6270 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6271
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6272<p>If the condition is a vector of i1, then the value arguments must be vectors
6273 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6274
6275<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6276<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]6277 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6278</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6279
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6280</div>
6281
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]6282<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6283<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6284 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6285</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6287<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6288
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6289<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6290<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6291 &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]6292</pre>
6293
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6294<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6295<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6297<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6298<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6299
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6300<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6301 <li>The optional "tail" marker indicates that the callee function does not
6302 access any allocas or varargs in the caller. Note that calls may be
6303 marked "tail" even if they do not occur before
6304 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6305 present, the function call is eligible for tail call optimization,
6306 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6307 optimized into a jump</a>. The code generator may optimize calls marked
6308 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6309 sibling call optimization</a> when the caller and callee have
6310 matching signatures, or 2) forced tail call optimization when the
6311 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6312 <ul>
6313 <li>Caller and callee both have the calling
6314 convention <tt>fastcc</tt>.</li>
6315 <li>The call is in tail position (ret immediately follows call and ret
6316 uses value of call or is void).</li>
6317 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6318 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6319 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6320 constraints are met.</a></li>
6321 </ul>
6322 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6323
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6324 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6325 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6326 defaults to using C calling conventions. The calling convention of the
6327 call must match the calling convention of the target function, or else the
6328 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6329
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6330 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6331 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6332 '<tt>inreg</tt>' attributes are valid here.</li>
6333
6334 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6335 type of the return value. Functions that return no value are marked
6336 <tt><a href="#t_void">void</a></tt>.</li>
6337
6338 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6339 being invoked. The argument types must match the types implied by this
6340 signature. This type can be omitted if the function is not varargs and if
6341 the function type does not return a pointer to a function.</li>
6342
6343 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6344 be invoked. In most cases, this is a direct function invocation, but
6345 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6346 to function value.</li>
6347
6348 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6349 signature argument types and parameter attributes. All arguments must be
6350 of <a href="#t_firstclass">first class</a> type. If the function
6351 signature indicates the function accepts a variable number of arguments,
6352 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6353
6354 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6355 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6356 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6357</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6359<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6360<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6361 a specified function, with its incoming arguments bound to the specified
6362 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6363 function, control flow continues with the instruction after the function
6364 call, and the return value of the function is bound to the result
6365 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6366
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6367<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6368<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6369 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6370 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6371 %X = tail call i32 @foo() <i>; yields i32</i>
6372 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6373 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6374
6375 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6376 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6377 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6378 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6379 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6380 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6381</pre>
6382
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6383<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6384standard C99 library as being the C99 library functions, and may perform
6385optimizations or generate code for them under that assumption. This is
6386something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6387freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6388
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6389</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6390
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6391<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6392<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6393 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6394</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6395
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6396<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6397
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6398<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6399<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6400 &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]6401</pre>
6402
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6403<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6404<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6405 the "variable argument" area of a function call. It is used to implement the
6406 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6407
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6408<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6409<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6410 argument. It returns a value of the specified argument type and increments
6411 the <tt>va_list</tt> to point to the next argument. The actual type
6412 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6413
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6414<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6415<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6416 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6417 to the next argument. For more information, see the variable argument
6418 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6419
6420<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]6421 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6422 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6423
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6424<p><tt>va_arg</tt> is an LLVM instruction instead of
6425 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6426 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6427
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6428<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6429<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6430
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6431<p>Note that the code generator does not yet fully support va_arg on many
6432 targets. Also, it does not currently support va_arg with aggregate types on
6433 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6434
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6435</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6436
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6437<!-- _______________________________________________________________________ -->
6438<h4>
6439 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6440</h4>
6441
6442<div>
6443
6444<h5>Syntax:</h5>
6445<pre>
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6446 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6447 &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]6448
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6449 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6450 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
6454<p>The '<tt>landingpad</tt>' instruction is used by
6455 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6456 system</a> to specify that a basic block is a landing pad &mdash; one where
6457 the exception lands, and corresponds to the code found in the
6458 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6459 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6460 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6461 type <tt>resultty</tt>.</p>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6462
6463<h5>Arguments:</h5>
6464<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6465 function associated with the unwinding mechanism. The optional
6466 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6467
6468<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6469 or <tt>filter</tt> &mdash; and contains the global variable representing the
6470 "type" that may be caught or filtered respectively. Unlike the
6471 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6472 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6473 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6474 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6475
6476<h5>Semantics:</h5>
6477<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6478 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6479 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6480 calling conventions, how the personality function results are represented in
6481 LLVM IR is target specific.</p>
6482
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6483<p>The clauses are applied in order from top to bottom. If two
6484 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6485 clauses from the calling function are appended to the list of clauses.
6486 When the call stack is being unwound due to an exception being thrown, the
6487 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6488 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6489 unwinding continues further up the call stack.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6490
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6491<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6492
6493<ul>
6494 <li>A landing pad block is a basic block which is the unwind destination of an
6495 '<tt>invoke</tt>' instruction.</li>
6496 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6497 first non-PHI instruction.</li>
6498 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6499 pad block.</li>
6500 <li>A basic block that is not a landing pad block may not include a
6501 '<tt>landingpad</tt>' instruction.</li>
6502 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6503 personality function.</li>
6504</ul>
6505
6506<h5>Example:</h5>
6507<pre>
6508 ;; A landing pad which can catch an integer.
6509 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6510 catch i8** @_ZTIi
6511 ;; A landing pad that is a cleanup.
6512 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6513 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6514 ;; A landing pad which can catch an integer and can only throw a double.
6515 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6516 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6517 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6518</pre>
6519
6520</div>
6521
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6522</div>
6523
6524</div>
6525
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6526<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6527<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6528<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6529
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6530<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6531
6532<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6533 well known names and semantics and are required to follow certain
6534 restrictions. Overall, these intrinsics represent an extension mechanism for
6535 the LLVM language that does not require changing all of the transformations
6536 in LLVM when adding to the language (or the bitcode reader/writer, the
6537 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6538
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6539<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6540 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6541 begin with this prefix. Intrinsic functions must always be external
6542 functions: you cannot define the body of intrinsic functions. Intrinsic
6543 functions may only be used in call or invoke instructions: it is illegal to
6544 take the address of an intrinsic function. Additionally, because intrinsic
6545 functions are part of the LLVM language, it is required if any are added that
6546 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6547
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6548<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6549 family of functions that perform the same operation but on different data
6550 types. Because LLVM can represent over 8 million different integer types,
6551 overloading is used commonly to allow an intrinsic function to operate on any
6552 integer type. One or more of the argument types or the result type can be
6553 overloaded to accept any integer type. Argument types may also be defined as
6554 exactly matching a previous argument's type or the result type. This allows
6555 an intrinsic function which accepts multiple arguments, but needs all of them
6556 to be of the same type, to only be overloaded with respect to a single
6557 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6558
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6559<p>Overloaded intrinsics will have the names of its overloaded argument types
6560 encoded into its function name, each preceded by a period. Only those types
6561 which are overloaded result in a name suffix. Arguments whose type is matched
6562 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6563 can take an integer of any width and returns an integer of exactly the same
6564 integer width. This leads to a family of functions such as
6565 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6566 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6567 suffix is required. Because the argument's type is matched against the return
6568 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6569
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6570<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6571 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6572
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6573<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6574<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6575 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6576</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6577
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6578<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6579
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6580<p>Variable argument support is defined in LLVM with
6581 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6582 intrinsic functions. These functions are related to the similarly named
6583 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6584
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6585<p>All of these functions operate on arguments that use a target-specific value
6586 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6587 not define what this type is, so all transformations should be prepared to
6588 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6589
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6590<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]6591 instruction and the variable argument handling intrinsic functions are
6592 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6593
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6594<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6595define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6596 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6597 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6598 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6599 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6600
6601 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6602 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6603
6604 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6605 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6606 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6607 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6608 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6609
6610 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6611 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6612 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6613}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6614
6615declare void @llvm.va_start(i8*)
6616declare void @llvm.va_copy(i8*, i8*)
6617declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6618</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6619
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6620<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6621<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6622 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6623</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6624
6625
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6626<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6627
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6628<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6629<pre>
6630 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6631</pre>
6632
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6633<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6635 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]6636
6637<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6638<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]6639
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6640<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6641<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]6642 macro available in C. In a target-dependent way, it initializes
6643 the <tt>va_list</tt> element to which the argument points, so that the next
6644 call to <tt>va_arg</tt> will produce the first variable argument passed to
6645 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6646 need to know the last argument of the function as the compiler can figure
6647 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6648
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6649</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6650
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6651<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6652<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6653 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6654</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6655
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6656<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6657
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6658<h5>Syntax:</h5>
6659<pre>
6660 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6661</pre>
6662
6663<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6664<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6665 which has been initialized previously
6666 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6667 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6668
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6669<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6670<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]6671
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6672<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6673<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]6674 macro available in C. In a target-dependent way, it destroys
6675 the <tt>va_list</tt> element to which the argument points. Calls
6676 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6677 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6678 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6679
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6680</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6681
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6682<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6683<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6684 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6685</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6686
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6687<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6688
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6689<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6690<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6691 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6692</pre>
6693
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6694<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6695<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6696 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6697
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6698<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6699<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]6700 The second argument is a pointer to a <tt>va_list</tt> element to copy
6701 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6702
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6703<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6704<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]6705 macro available in C. In a target-dependent way, it copies the
6706 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6707 element. This intrinsic is necessary because
6708 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6709 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6710
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6711</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6712
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6713</div>
6714
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6715<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6716<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6717 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6718</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6719
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6720<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6721
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6722<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6723Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6724intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6725roots on the stack</a>, as well as garbage collector implementations that
6726require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6727barriers. Front-ends for type-safe garbage collected languages should generate
6728these intrinsics to make use of the LLVM garbage collectors. For more details,
6729see <a href="GarbageCollection.html">Accurate Garbage Collection with
6730LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6731
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6732<p>The garbage collection intrinsics only operate on objects in the generic
6733 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6734
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6735<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6736<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6737 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6738</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6739
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6740<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6741
6742<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6743<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6744 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6745</pre>
6746
6747<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6748<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]6749 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6750
6751<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6752<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6753 root pointer. The second pointer (which must be either a constant or a
6754 global value address) contains the meta-data to be associated with the
6755 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6756
6757<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6758<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]6759 location. At compile-time, the code generator generates information to allow
6760 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6761 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6762 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6763
6764</div>
6765
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6767<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6768 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6769</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6770
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6771<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6772
6773<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6774<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6775 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6776</pre>
6777
6778<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6779<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6780 locations, allowing garbage collector implementations that require read
6781 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6782
6783<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6784<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]6785 allocated from the garbage collector. The first object is a pointer to the
6786 start of the referenced object, if needed by the language runtime (otherwise
6787 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6788
6789<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6790<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6791 instruction, but may be replaced with substantially more complex code by the
6792 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6793 may only be used in a function which <a href="#gc">specifies a GC
6794 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6795
6796</div>
6797
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6798<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6799<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6800 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6801</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6802
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6803<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6804
6805<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6806<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6807 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6808</pre>
6809
6810<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6811<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6812 locations, allowing garbage collector implementations that require write
6813 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6814
6815<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6816<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]6817 object to store it to, and the third is the address of the field of Obj to
6818 store to. If the runtime does not require a pointer to the object, Obj may
6819 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6820
6821<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6822<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6823 instruction, but may be replaced with substantially more complex code by the
6824 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6825 may only be used in a function which <a href="#gc">specifies a GC
6826 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6827
6828</div>
6829
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6830</div>
6831
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6832<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6833<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6834 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6835</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6837<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6838
6839<p>These intrinsics are provided by LLVM to expose special features that may
6840 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6841
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6842<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6843<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6844 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6845</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6846
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6847<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6848
6849<h5>Syntax:</h5>
6850<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6851 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6852</pre>
6853
6854<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6855<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6856 target-specific value indicating the return address of the current function
6857 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6858
6859<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6860<p>The argument to this intrinsic indicates which function to return the address
6861 for. Zero indicates the calling function, one indicates its caller, etc.
6862 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6863
6864<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6865<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6866 indicating the return address of the specified call frame, or zero if it
6867 cannot be identified. The value returned by this intrinsic is likely to be
6868 incorrect or 0 for arguments other than zero, so it should only be used for
6869 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6870
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6871<p>Note that calling this intrinsic does not prevent function inlining or other
6872 aggressive transformations, so the value returned may not be that of the
6873 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6874
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6875</div>
6876
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6877<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6878<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6879 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6880</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6881
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6882<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6883
6884<h5>Syntax:</h5>
6885<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6886 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6887</pre>
6888
6889<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6890<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6891 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6892
6893<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6894<p>The argument to this intrinsic indicates which function to return the frame
6895 pointer for. Zero indicates the calling function, one indicates its caller,
6896 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6897
6898<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6899<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6900 indicating the frame address of the specified call frame, or zero if it
6901 cannot be identified. The value returned by this intrinsic is likely to be
6902 incorrect or 0 for arguments other than zero, so it should only be used for
6903 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6904
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6905<p>Note that calling this intrinsic does not prevent function inlining or other
6906 aggressive transformations, so the value returned may not be that of the
6907 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6908
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6909</div>
6910
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6911<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6912<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6913 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6914</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6915
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6916<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6917
6918<h5>Syntax:</h5>
6919<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6920 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6921</pre>
6922
6923<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6924<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6925 of the function stack, for use
6926 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6927 useful for implementing language features like scoped automatic variable
6928 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6929
6930<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6931<p>This intrinsic returns a opaque pointer value that can be passed
6932 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6933 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6934 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6935 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6936 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6937 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6938
6939</div>
6940
6941<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6942<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6943 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6944</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6945
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6946<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6947
6948<h5>Syntax:</h5>
6949<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6950 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6951</pre>
6952
6953<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6954<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6955 the function stack to the state it was in when the
6956 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6957 executed. This is useful for implementing language features like scoped
6958 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6959
6960<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6961<p>See the description
6962 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6963
6964</div>
6965
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6966<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6967<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6968 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6969</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6970
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6971<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6972
6973<h5>Syntax:</h5>
6974<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6975 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]6976</pre>
6977
6978<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6979<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6980 insert a prefetch instruction if supported; otherwise, it is a noop.
6981 Prefetches have no effect on the behavior of the program but can change its
6982 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6983
6984<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6985<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6986 specifier determining if the fetch should be for a read (0) or write (1),
6987 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6988 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6989 specifies whether the prefetch is performed on the data (1) or instruction (0)
6990 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6991 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6992
6993<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6994<p>This intrinsic does not modify the behavior of the program. In particular,
6995 prefetches cannot trap and do not produce a value. On targets that support
6996 this intrinsic, the prefetch can provide hints to the processor cache for
6997 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6998
6999</div>
7000
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7001<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7002<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7003 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7004</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7005
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7006<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7007
7008<h5>Syntax:</h5>
7009<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]7010 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7011</pre>
7012
7013<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
7015 Counter (PC) in a region of code to simulators and other tools. The method
7016 is target specific, but it is expected that the marker will use exported
7017 symbols to transmit the PC of the marker. The marker makes no guarantees
7018 that it will remain with any specific instruction after optimizations. It is
7019 possible that the presence of a marker will inhibit optimizations. The
7020 intended use is to be inserted after optimizations to allow correlations of
7021 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7022
7023<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7024<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7025
7026<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7027<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7028 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]7029
7030</div>
7031
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7032<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7033<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7034 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7035</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7036
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7037<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7038
7039<h5>Syntax:</h5>
7040<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7041 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7042</pre>
7043
7044<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7045<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7046 counter register (or similar low latency, high accuracy clocks) on those
7047 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7048 should map to RPCC. As the backing counters overflow quickly (on the order
7049 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7052<p>When directly supported, reading the cycle counter should not modify any
7053 memory. Implementations are allowed to either return a application specific
7054 value or a system wide value. On backends without support, this is lowered
7055 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7056
7057</div>
7058
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7059</div>
7060
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7061<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7062<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7063 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7064</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7065
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7066<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7067
7068<p>LLVM provides intrinsics for a few important standard C library functions.
7069 These intrinsics allow source-language front-ends to pass information about
7070 the alignment of the pointer arguments to the code generator, providing
7071 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7072
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7073<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7074<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7075 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7076</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7077
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7078<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7079
7080<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7081<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]7082 integer bit width and for different address spaces. Not all targets support
7083 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7084
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7085<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7086 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]7087 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7088 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]7089 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7090</pre>
7091
7092<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7094 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7095
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7096<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7097 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7098 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7099
7100<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>The first argument is a pointer to the destination, the second is a pointer
7103 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7104 number of bytes to copy, the fourth argument is the alignment of the
7105 source and destination locations, and the fifth is a boolean indicating a
7106 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7107
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7108<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]7109 then the caller guarantees that both the source and destination pointers are
7110 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7111
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7112<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7113 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7114 The detailed access behavior is not very cleanly specified and it is unwise
7115 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7116
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7117<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7118
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7119<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7120 source location to the destination location, which are not allowed to
7121 overlap. It copies "len" bytes of memory over. If the argument is known to
7122 be aligned to some boundary, this can be specified as the fourth argument,
7123 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7124
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7125</div>
7126
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7127<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7128<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7129 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7130</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7131
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7132<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7133
7134<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7135<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]7136 width and for different address space. Not all targets support all bit
7137 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7138
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7139<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7140 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]7141 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7142 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]7143 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7144</pre>
7145
7146<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7147<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7148 source location to the destination location. It is similar to the
7149 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7150 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7151
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7152<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7153 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7154 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7155
7156<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7157
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7158<p>The first argument is a pointer to the destination, the second is a pointer
7159 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7160 number of bytes to copy, the fourth argument is the alignment of the
7161 source and destination locations, and the fifth is a boolean indicating a
7162 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7163
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7164<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]7165 then the caller guarantees that the source and destination pointers are
7166 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7167
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7168<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7169 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7170 The detailed access behavior is not very cleanly specified and it is unwise
7171 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7172
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7173<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7174
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7175<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7176 source location to the destination location, which may overlap. It copies
7177 "len" bytes of memory over. If the argument is known to be aligned to some
7178 boundary, this can be specified as the fourth argument, otherwise it should
7179 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7180
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7181</div>
7182
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7183<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7184<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7185 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7186</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7187
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7188<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7189
7190<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7191<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]7192 width and for different address spaces. However, not all targets support all
7193 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7194
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7195<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7196 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7197 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7198 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7199 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7204 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7205
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7206<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7207 intrinsic does not return a value and takes extra alignment/volatile
7208 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7209
7210<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7211<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]7212 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7213 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7214 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +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 destination pointer is aligned to that
7218 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +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.memset</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 Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7225<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7226<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7227 at the destination location. If the argument is known to be aligned to some
7228 boundary, this can be specified as the fourth argument, otherwise it should
7229 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7230
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7231</div>
7232
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7233<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7234<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7235 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7236</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7237
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7238<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7239
7240<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7241<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7242 floating point or vector of floating point type. Not all targets support all
7243 types however.</p>
7244
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7245<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7246 declare float @llvm.sqrt.f32(float %Val)
7247 declare double @llvm.sqrt.f64(double %Val)
7248 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7249 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7250 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7251</pre>
7252
7253<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7254<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7255 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7256 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7257 behavior for negative numbers other than -0.0 (which allows for better
7258 optimization, because there is no need to worry about errno being
7259 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]7260
7261<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7262<p>The argument and return value are floating point numbers of the same
7263 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7264
7265<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7266<p>This function returns the sqrt of the specified operand if it is a
7267 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7268
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7269</div>
7270
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7271<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7272<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7273 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7274</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7275
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7276<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7277
7278<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7279<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7280 floating point or vector of floating point type. Not all targets support all
7281 types however.</p>
7282
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7283<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7284 declare float @llvm.powi.f32(float %Val, i32 %power)
7285 declare double @llvm.powi.f64(double %Val, i32 %power)
7286 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7287 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7288 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7289</pre>
7290
7291<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7292<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7293 specified (positive or negative) power. The order of evaluation of
7294 multiplications is not defined. When a vector of floating point type is
7295 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7296
7297<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7298<p>The second argument is an integer power, and the first is a value to raise to
7299 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7300
7301<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7302<p>This function returns the first value raised to the second power with an
7303 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7304
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7305</div>
7306
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7307<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7308<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7309 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7310</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7311
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7312<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7313
7314<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7315<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7316 floating point or vector of floating point type. Not all targets support all
7317 types however.</p>
7318
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7319<pre>
7320 declare float @llvm.sin.f32(float %Val)
7321 declare double @llvm.sin.f64(double %Val)
7322 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7323 declare fp128 @llvm.sin.f128(fp128 %Val)
7324 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7325</pre>
7326
7327<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7328<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7329
7330<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331<p>The argument and return value are floating point numbers of the same
7332 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7333
7334<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7335<p>This function returns the sine of the specified operand, returning the same
7336 values as the libm <tt>sin</tt> functions would, and handles error conditions
7337 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7338
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7339</div>
7340
7341<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7342<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7343 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7344</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7345
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7346<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7347
7348<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7349<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7350 floating point or vector of floating point type. Not all targets support all
7351 types however.</p>
7352
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7353<pre>
7354 declare float @llvm.cos.f32(float %Val)
7355 declare double @llvm.cos.f64(double %Val)
7356 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7357 declare fp128 @llvm.cos.f128(fp128 %Val)
7358 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7359</pre>
7360
7361<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7362<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7363
7364<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7365<p>The argument and return value are floating point numbers of the same
7366 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7367
7368<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369<p>This function returns the cosine of the specified operand, returning the same
7370 values as the libm <tt>cos</tt> functions would, and handles error conditions
7371 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7372
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7373</div>
7374
7375<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7376<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7377 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7378</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7379
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7380<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7381
7382<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7383<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7384 floating point or vector of floating point type. Not all targets support all
7385 types however.</p>
7386
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7387<pre>
7388 declare float @llvm.pow.f32(float %Val, float %Power)
7389 declare double @llvm.pow.f64(double %Val, double %Power)
7390 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7391 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7392 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7393</pre>
7394
7395<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7396<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7397 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7398
7399<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7400<p>The second argument is a floating point power, and the first is a value to
7401 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7402
7403<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7404<p>This function returns the first value raised to the second power, returning
7405 the same values as the libm <tt>pow</tt> functions would, and handles error
7406 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7407
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7408</div>
7409
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7410<!-- _______________________________________________________________________ -->
7411<h4>
7412 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7413</h4>
7414
7415<div>
7416
7417<h5>Syntax:</h5>
7418<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7419 floating point or vector of floating point type. Not all targets support all
7420 types however.</p>
7421
7422<pre>
7423 declare float @llvm.exp.f32(float %Val)
7424 declare double @llvm.exp.f64(double %Val)
7425 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7426 declare fp128 @llvm.exp.f128(fp128 %Val)
7427 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7428</pre>
7429
7430<h5>Overview:</h5>
7431<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7432
7433<h5>Arguments:</h5>
7434<p>The argument and return value are floating point numbers of the same
7435 type.</p>
7436
7437<h5>Semantics:</h5>
7438<p>This function returns the same values as the libm <tt>exp</tt> functions
7439 would, and handles error conditions in the same way.</p>
7440
7441</div>
7442
7443<!-- _______________________________________________________________________ -->
7444<h4>
7445 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7446</h4>
7447
7448<div>
7449
7450<h5>Syntax:</h5>
7451<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7452 floating point or vector of floating point type. Not all targets support all
7453 types however.</p>
7454
7455<pre>
7456 declare float @llvm.log.f32(float %Val)
7457 declare double @llvm.log.f64(double %Val)
7458 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7459 declare fp128 @llvm.log.f128(fp128 %Val)
7460 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7461</pre>
7462
7463<h5>Overview:</h5>
7464<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7465
7466<h5>Arguments:</h5>
7467<p>The argument and return value are floating point numbers of the same
7468 type.</p>
7469
7470<h5>Semantics:</h5>
7471<p>This function returns the same values as the libm <tt>log</tt> functions
7472 would, and handles error conditions in the same way.</p>
7473
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7474</div>
7475
7476<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7477<h4>
7478 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7479</h4>
7480
7481<div>
7482
7483<h5>Syntax:</h5>
7484<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7485 floating point or vector of floating point type. Not all targets support all
7486 types however.</p>
7487
7488<pre>
7489 declare float @llvm.fma.f32(float %a, float %b, float %c)
7490 declare double @llvm.fma.f64(double %a, double %b, double %c)
7491 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7492 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7493 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7494</pre>
7495
7496<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7497<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7498 operation.</p>
7499
7500<h5>Arguments:</h5>
7501<p>The argument and return value are floating point numbers of the same
7502 type.</p>
7503
7504<h5>Semantics:</h5>
7505<p>This function returns the same values as the libm <tt>fma</tt> functions
7506 would.</p>
7507
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7508</div>
7509
Peter Collingbourne2165cf62012-07-03 12:25:40 +0000[diff] [blame^]7510<!-- _______________________________________________________________________ -->
7511<h4>
7512 <a name="int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a>
7513</h4>
7514
7515<div>
7516
7517<h5>Syntax:</h5>
7518<p>This is an overloaded intrinsic. You can use <tt>llvm.fabs</tt> on any
7519 floating point or vector of floating point type. Not all targets support all
7520 types however.</p>
7521
7522<pre>
7523 declare float @llvm.fabs.f32(float %Val)
7524 declare double @llvm.fabs.f64(double %Val)
7525 declare x86_fp80 @llvm.fabs.f80(x86_fp80 %Val)
7526 declare fp128 @llvm.fabs.f128(fp128 %Val)
7527 declare ppc_fp128 @llvm.fabs.ppcf128(ppc_fp128 %Val)
7528</pre>
7529
7530<h5>Overview:</h5>
7531<p>The '<tt>llvm.fabs.*</tt>' intrinsics return the absolute value of
7532 the operand.</p>
7533
7534<h5>Arguments:</h5>
7535<p>The argument and return value are floating point numbers of the same
7536 type.</p>
7537
7538<h5>Semantics:</h5>
7539<p>This function returns the same values as the libm <tt>fabs</tt> functions
7540 would, and handles error conditions in the same way.</p>
7541
7542</div>
7543
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7544</div>
7545
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7546<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7547<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7548 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7549</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7550
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7551<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7552
7553<p>LLVM provides intrinsics for a few important bit manipulation operations.
7554 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7555
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7556<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7557<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7558 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7559</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7560
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7561<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7562
7563<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7564<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7565 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7566
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7567<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7568 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7569 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7570 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7571</pre>
7572
7573<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7574<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7575 values with an even number of bytes (positive multiple of 16 bits). These
7576 are useful for performing operations on data that is not in the target's
7577 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7578
7579<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7580<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7581 and low byte of the input i16 swapped. Similarly,
7582 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7583 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7584 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7585 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7586 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7587 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7588
7589</div>
7590
7591<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7592<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7593 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7594</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7595
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7596<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7597
7598<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7599<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]7600 width, or on any vector with integer elements. Not all targets support all
7601 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7602
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7603<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7604 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7605 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7606 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7607 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7608 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7609 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]7610</pre>
7611
7612<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7613<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7614 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7615
7616<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7617<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]7618 integer type, or a vector with integer elements.
7619 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7620
7621<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7622<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7623 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7624
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7625</div>
7626
7627<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7628<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7629 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7630</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7631
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7632<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7633
7634<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7635<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]7636 integer bit width, or any vector whose elements are integers. Not all
7637 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7638
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7639<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7640 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7641 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7642 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7643 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7644 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7645 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]7646</pre>
7647
7648<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7649<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7650 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7651
7652<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7653<p>The first argument is the value to be counted. This argument may be of any
7654 integer type, or a vectory with integer element type. The return type
7655 must match the first argument type.</p>
7656
7657<p>The second argument must be a constant and is a flag to indicate whether the
7658 intrinsic should ensure that a zero as the first argument produces a defined
7659 result. Historically some architectures did not provide a defined result for
7660 zero values as efficiently, and many algorithms are now predicated on
7661 avoiding zero-value inputs.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7662
7663<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7664<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7665 zeros in a variable, or within each element of the vector.
7666 If <tt>src == 0</tt> then the result is the size in bits of the type of
7667 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7668 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7669
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7670</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7671
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7672<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7673<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7674 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7675</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7676
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7677<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7678
7679<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7680<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]7681 integer bit width, or any vector of integer elements. Not all targets
7682 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7683
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7684<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7685 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7686 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7687 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7688 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7689 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7690 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]7691</pre>
7692
7693<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7694<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7695 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7696
7697<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7698<p>The first argument is the value to be counted. This argument may be of any
7699 integer type, or a vectory with integer element type. The return type
7700 must match the first argument type.</p>
7701
7702<p>The second argument must be a constant and is a flag to indicate whether the
7703 intrinsic should ensure that a zero as the first argument produces a defined
7704 result. Historically some architectures did not provide a defined result for
7705 zero values as efficiently, and many algorithms are now predicated on
7706 avoiding zero-value inputs.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7707
7708<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7709<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7710 zeros in a variable, or within each element of a vector.
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7711 If <tt>src == 0</tt> then the result is the size in bits of the type of
7712 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7713 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7714
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7715</div>
7716
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7717</div>
7718
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7719<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7720<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7721 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7722</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7723
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7724<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7725
7726<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7727
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7728<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7729<h4>
7730 <a name="int_sadd_overflow">
7731 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7732 </a>
7733</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7734
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7735<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7736
7737<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7738<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]7739 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7740
7741<pre>
7742 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7743 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7744 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7745</pre>
7746
7747<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7748<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7749 a signed addition of the two arguments, and indicate whether an overflow
7750 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7751
7752<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7753<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]7754 be of integer types of any bit width, but they must have the same bit
7755 width. The second element of the result structure must be of
7756 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7757 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7758
7759<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7760<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7761 a signed addition of the two variables. They return a structure &mdash; the
7762 first element of which is the signed summation, and the second element of
7763 which is a bit specifying if the signed summation resulted in an
7764 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7765
7766<h5>Examples:</h5>
7767<pre>
7768 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7769 %sum = extractvalue {i32, i1} %res, 0
7770 %obit = extractvalue {i32, i1} %res, 1
7771 br i1 %obit, label %overflow, label %normal
7772</pre>
7773
7774</div>
7775
7776<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7777<h4>
7778 <a name="int_uadd_overflow">
7779 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7780 </a>
7781</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7782
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7783<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7784
7785<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7786<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]7787 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7788
7789<pre>
7790 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7791 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7792 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7793</pre>
7794
7795<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7796<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7797 an unsigned addition of the two arguments, and indicate whether a carry
7798 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7799
7800<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7801<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]7802 be of integer types of any bit width, but they must have the same bit
7803 width. The second element of the result structure must be of
7804 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7805 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7806
7807<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7808<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7809 an unsigned addition of the two arguments. They return a structure &mdash;
7810 the first element of which is the sum, and the second element of which is a
7811 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7812
7813<h5>Examples:</h5>
7814<pre>
7815 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7816 %sum = extractvalue {i32, i1} %res, 0
7817 %obit = extractvalue {i32, i1} %res, 1
7818 br i1 %obit, label %carry, label %normal
7819</pre>
7820
7821</div>
7822
7823<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7824<h4>
7825 <a name="int_ssub_overflow">
7826 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7827 </a>
7828</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7829
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7830<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7831
7832<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7833<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]7834 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7835
7836<pre>
7837 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7838 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7839 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7840</pre>
7841
7842<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7843<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7844 a signed subtraction of the two arguments, and indicate whether an overflow
7845 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7846
7847<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7848<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]7849 be of integer types of any bit width, but they must have the same bit
7850 width. The second element of the result structure must be of
7851 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7852 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7853
7854<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7855<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7856 a signed subtraction of the two arguments. They return a structure &mdash;
7857 the first element of which is the subtraction, and the second element of
7858 which is a bit specifying if the signed subtraction resulted in an
7859 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7860
7861<h5>Examples:</h5>
7862<pre>
7863 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7864 %sum = extractvalue {i32, i1} %res, 0
7865 %obit = extractvalue {i32, i1} %res, 1
7866 br i1 %obit, label %overflow, label %normal
7867</pre>
7868
7869</div>
7870
7871<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7872<h4>
7873 <a name="int_usub_overflow">
7874 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7875 </a>
7876</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7878<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7879
7880<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7881<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]7882 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7883
7884<pre>
7885 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7886 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7887 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7888</pre>
7889
7890<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7891<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7892 an unsigned subtraction of the two arguments, and indicate whether an
7893 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7894
7895<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7896<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]7897 be of integer types of any bit width, but they must have the same bit
7898 width. The second element of the result structure must be of
7899 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7900 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7901
7902<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7903<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7904 an unsigned subtraction of the two arguments. They return a structure &mdash;
7905 the first element of which is the subtraction, and the second element of
7906 which is a bit specifying if the unsigned subtraction resulted in an
7907 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7908
7909<h5>Examples:</h5>
7910<pre>
7911 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7912 %sum = extractvalue {i32, i1} %res, 0
7913 %obit = extractvalue {i32, i1} %res, 1
7914 br i1 %obit, label %overflow, label %normal
7915</pre>
7916
7917</div>
7918
7919<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7920<h4>
7921 <a name="int_smul_overflow">
7922 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7923 </a>
7924</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7925
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7926<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7927
7928<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7929<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]7930 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7931
7932<pre>
7933 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7934 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7935 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7936</pre>
7937
7938<h5>Overview:</h5>
7939
7940<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7941 a signed multiplication of the two arguments, and indicate whether an
7942 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7943
7944<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7945<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]7946 be of integer types of any bit width, but they must have the same bit
7947 width. The second element of the result structure must be of
7948 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7949 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7950
7951<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7952<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7953 a signed multiplication of the two arguments. They return a structure &mdash;
7954 the first element of which is the multiplication, and the second element of
7955 which is a bit specifying if the signed multiplication resulted in an
7956 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7957
7958<h5>Examples:</h5>
7959<pre>
7960 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7961 %sum = extractvalue {i32, i1} %res, 0
7962 %obit = extractvalue {i32, i1} %res, 1
7963 br i1 %obit, label %overflow, label %normal
7964</pre>
7965
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7966</div>
7967
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7968<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7969<h4>
7970 <a name="int_umul_overflow">
7971 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7972 </a>
7973</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7974
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7975<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7976
7977<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7978<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]7979 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7980
7981<pre>
7982 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7983 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7984 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7985</pre>
7986
7987<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7988<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7989 a unsigned multiplication of the two arguments, and indicate whether an
7990 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7991
7992<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7993<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]7994 be of integer types of any bit width, but they must have the same bit
7995 width. The second element of the result structure must be of
7996 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7997 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7998
7999<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8000<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8001 an unsigned multiplication of the two arguments. They return a structure
8002 &mdash; the first element of which is the multiplication, and the second
8003 element of which is a bit specifying if the unsigned multiplication resulted
8004 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]8005
8006<h5>Examples:</h5>
8007<pre>
8008 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8009 %sum = extractvalue {i32, i1} %res, 0
8010 %obit = extractvalue {i32, i1} %res, 1
8011 br i1 %obit, label %overflow, label %normal
8012</pre>
8013
8014</div>
8015
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8016</div>
8017
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8018<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8019<h3>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]8020 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
8021</h3>
8022
8023<!-- _______________________________________________________________________ -->
8024
8025<h4>
8026 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
8027</h4>
8028
8029<div>
8030
8031<h5>Syntax:</h5>
8032<pre>
8033 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
8034 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
8035</pre>
8036
8037<h5>Overview:</h5>
8038<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
8039expressions that can be fused if the code generator determines that the fused
8040expression would be legal and efficient.</p>
8041
8042<h5>Arguments:</h5>
8043<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
8044multiplicands, a and b, and an addend c.</p>
8045
8046<h5>Semantics:</h5>
8047<p>The expression:</p>
8048<pre>
8049 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
8050</pre>
8051<p>is equivalent to the expression a * b + c, except that rounding will not be
8052performed between the multiplication and addition steps if the code generator
8053fuses the operations. Fusion is not guaranteed, even if the target platform
8054supports it. If a fused multiply-add is required the corresponding llvm.fma.*
8055intrinsic function should be used instead.</p>
8056
8057<h5>Examples:</h5>
8058<pre>
8059 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
8060</pre>
8061
8062</div>
8063
8064<!-- ======================================================================= -->
8065<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8066 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8067</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8068
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8069<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8070
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]8071<p>For most target platforms, half precision floating point is a storage-only
8072 format. This means that it is
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8073 a dense encoding (in memory) but does not support computation in the
8074 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8075
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8076<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8077 value as an i16, then convert it to float with <a
8078 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8079 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8080 double etc). To store the value back to memory, it is first converted to
8081 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8082 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8083 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8084
8085<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8086<h4>
8087 <a name="int_convert_to_fp16">
8088 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8089 </a>
8090</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8091
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8092<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8093
8094<h5>Syntax:</h5>
8095<pre>
8096 declare i16 @llvm.convert.to.fp16(f32 %a)
8097</pre>
8098
8099<h5>Overview:</h5>
8100<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8101 a conversion from single precision floating point format to half precision
8102 floating point format.</p>
8103
8104<h5>Arguments:</h5>
8105<p>The intrinsic function contains single argument - the value to be
8106 converted.</p>
8107
8108<h5>Semantics:</h5>
8109<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8110 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8111 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8112 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8113
8114<h5>Examples:</h5>
8115<pre>
8116 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8117 store i16 %res, i16* @x, align 2
8118</pre>
8119
8120</div>
8121
8122<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8123<h4>
8124 <a name="int_convert_from_fp16">
8125 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8126 </a>
8127</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8130
8131<h5>Syntax:</h5>
8132<pre>
8133 declare f32 @llvm.convert.from.fp16(i16 %a)
8134</pre>
8135
8136<h5>Overview:</h5>
8137<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8138 a conversion from half precision floating point format to single precision
8139 floating point format.</p>
8140
8141<h5>Arguments:</h5>
8142<p>The intrinsic function contains single argument - the value to be
8143 converted.</p>
8144
8145<h5>Semantics:</h5>
8146<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8147 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8148 precision floating point format. The input half-float value is represented by
8149 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8150
8151<h5>Examples:</h5>
8152<pre>
8153 %a = load i16* @x, align 2
8154 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8155</pre>
8156
8157</div>
8158
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8159</div>
8160
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8161<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8162<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8163 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8164</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8165
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8166<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8167
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8168<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8169 prefix), are described in
8170 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8171 Level Debugging</a> document.</p>
8172
8173</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8174
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8175<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8176<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8177 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8178</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8179
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8180<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8181
8182<p>The LLVM exception handling intrinsics (which all start with
8183 <tt>llvm.eh.</tt> prefix), are described in
8184 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8185 Handling</a> document.</p>
8186
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8187</div>
8188
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8189<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8190<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8191 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8192</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8193
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8194<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8195
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8196<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]8197 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8198 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8199 function pointer lacking the nest parameter - the caller does not need to
8200 provide a value for it. Instead, the value to use is stored in advance in a
8201 "trampoline", a block of memory usually allocated on the stack, which also
8202 contains code to splice the nest value into the argument list. This is used
8203 to implement the GCC nested function address extension.</p>
8204
8205<p>For example, if the function is
8206 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8207 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8208 follows:</p>
8209
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]8210<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8211 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8212 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8213 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8214 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8215 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8216</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8217
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8218<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8219 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8220
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8221<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8222<h4>
8223 <a name="int_it">
8224 '<tt>llvm.init.trampoline</tt>' Intrinsic
8225 </a>
8226</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8228<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8229
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8230<h5>Syntax:</h5>
8231<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8232 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]8233</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8234
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8235<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8236<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8237 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8238
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8239<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8240<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8241 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8242 sufficiently aligned block of memory; this memory is written to by the
8243 intrinsic. Note that the size and the alignment are target-specific - LLVM
8244 currently provides no portable way of determining them, so a front-end that
8245 generates this intrinsic needs to have some target-specific knowledge.
8246 The <tt>func</tt> argument must hold a function bitcast to
8247 an <tt>i8*</tt>.</p>
8248
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8249<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8250<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]8251 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8252 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8253 which can be <a href="#int_trampoline">bitcast (to a new function) and
8254 called</a>. The new function's signature is the same as that of
8255 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8256 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8257 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8258 with the same argument list, but with <tt>nval</tt> used for the missing
8259 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8260 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8261 to the returned function pointer is undefined.</p>
8262</div>
8263
8264<!-- _______________________________________________________________________ -->
8265<h4>
8266 <a name="int_at">
8267 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8268 </a>
8269</h4>
8270
8271<div>
8272
8273<h5>Syntax:</h5>
8274<pre>
8275 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8276</pre>
8277
8278<h5>Overview:</h5>
8279<p>This performs any required machine-specific adjustment to the address of a
8280 trampoline (passed as <tt>tramp</tt>).</p>
8281
8282<h5>Arguments:</h5>
8283<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8284 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8285 </a>.</p>
8286
8287<h5>Semantics:</h5>
8288<p>On some architectures the address of the code to be executed needs to be
8289 different to the address where the trampoline is actually stored. This
8290 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8291 after performing the required machine specific adjustments.
8292 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8293 executed</a>.
8294</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8295
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8296</div>
8297
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8298</div>
8299
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8300<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8301<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8302 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8303</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8304
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8305<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8306
8307<p>This class of intrinsics exists to information about the lifetime of memory
8308 objects and ranges where variables are immutable.</p>
8309
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8310<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8311<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8312 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8313</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8314
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8315<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8316
8317<h5>Syntax:</h5>
8318<pre>
8319 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8320</pre>
8321
8322<h5>Overview:</h5>
8323<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8324 object's lifetime.</p>
8325
8326<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8327<p>The first argument is a constant integer representing the size of the
8328 object, or -1 if it is variable sized. The second argument is a pointer to
8329 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8330
8331<h5>Semantics:</h5>
8332<p>This intrinsic indicates that before this point in the code, the value of the
8333 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]8334 never be used and has an undefined value. A load from the pointer that
8335 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8336 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8337
8338</div>
8339
8340<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8341<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8342 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8343</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8344
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8345<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8346
8347<h5>Syntax:</h5>
8348<pre>
8349 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8350</pre>
8351
8352<h5>Overview:</h5>
8353<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8354 object's lifetime.</p>
8355
8356<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8357<p>The first argument is a constant integer representing the size of the
8358 object, or -1 if it is variable sized. The second argument is a pointer to
8359 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8360
8361<h5>Semantics:</h5>
8362<p>This intrinsic indicates that after this point in the code, the value of the
8363 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8364 never be used and has an undefined value. Any stores into the memory object
8365 following this intrinsic may be removed as dead.
8366
8367</div>
8368
8369<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8370<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8371 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8372</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8373
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8374<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8375
8376<h5>Syntax:</h5>
8377<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8378 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8379</pre>
8380
8381<h5>Overview:</h5>
8382<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8383 a memory object will not change.</p>
8384
8385<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8386<p>The first argument is a constant integer representing the size of the
8387 object, or -1 if it is variable sized. The second argument is a pointer to
8388 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8389
8390<h5>Semantics:</h5>
8391<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8392 the return value, the referenced memory location is constant and
8393 unchanging.</p>
8394
8395</div>
8396
8397<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8398<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8399 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8400</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8401
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8402<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8403
8404<h5>Syntax:</h5>
8405<pre>
8406 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8407</pre>
8408
8409<h5>Overview:</h5>
8410<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8411 a memory object are mutable.</p>
8412
8413<h5>Arguments:</h5>
8414<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8415 The second argument is a constant integer representing the size of the
8416 object, or -1 if it is variable sized and the third argument is a pointer
8417 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8418
8419<h5>Semantics:</h5>
8420<p>This intrinsic indicates that the memory is mutable again.</p>
8421
8422</div>
8423
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8424</div>
8425
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8426<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8427<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8428 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8429</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8432
8433<p>This class of intrinsics is designed to be generic and has no specific
8434 purpose.</p>
8435
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8436<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8437<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8438 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8439</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8440
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8441<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8442
8443<h5>Syntax:</h5>
8444<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8445 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]8446</pre>
8447
8448<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8449<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8450
8451<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8452<p>The first argument is a pointer to a value, the second is a pointer to a
8453 global string, the third is a pointer to a global string which is the source
8454 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8455
8456<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8457<p>This intrinsic allows annotation of local variables with arbitrary strings.
8458 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8459 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8460 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8461
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8462</div>
8463
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8464<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8465<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8466 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8467</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8468
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8469<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8470
8471<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8472<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8473 any integer bit width.</p>
8474
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8475<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8476 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8477 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8478 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8479 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8480 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]8481</pre>
8482
8483<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8484<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8485
8486<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8487<p>The first argument is an integer value (result of some expression), the
8488 second is a pointer to a global string, the third is a pointer to a global
8489 string which is the source file name, and the last argument is the line
8490 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8491
8492<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8493<p>This intrinsic allows annotations to be put on arbitrary expressions with
8494 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8495 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8496 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8497
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8498</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8499
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8500<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8501<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8502 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8503</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8504
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8505<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8506
8507<h5>Syntax:</h5>
8508<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8509 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8510</pre>
8511
8512<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8513<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8514
8515<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8516<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8517
8518<h5>Semantics:</h5>
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8519<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8520 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8521 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8522
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8523</div>
8524
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8525<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8526<h4>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8527 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8528</h4>
8529
8530<div>
8531
8532<h5>Syntax:</h5>
8533<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8534 declare void @llvm.debugtrap() nounwind
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8535</pre>
8536
8537<h5>Overview:</h5>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8538<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8539
8540<h5>Arguments:</h5>
8541<p>None.</p>
8542
8543<h5>Semantics:</h5>
8544<p>This intrinsic is lowered to code which is intended to cause an execution
8545 trap with the intention of requesting the attention of a debugger.</p>
8546
8547</div>
8548
8549<!-- _______________________________________________________________________ -->
8550<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8551 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8552</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8553
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8554<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8555
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8556<h5>Syntax:</h5>
8557<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8558 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8559</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8560
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8561<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8562<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8563 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8564 ensure that it is placed on the stack before local variables.</p>
8565
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8566<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8567<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8568 arguments. The first argument is the value loaded from the stack
8569 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8570 that has enough space to hold the value of the guard.</p>
8571
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8572<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8573<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8574 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8575 stack. This is to ensure that if a local variable on the stack is
8576 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8577 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8578 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8579 function.</p>
8580
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8581</div>
8582
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8583<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8584<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8585 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8586</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8588<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8589
8590<h5>Syntax:</h5>
8591<pre>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8592 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8593 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8594</pre>
8595
8596<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8597<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8598 the optimizers to determine at compile time whether a) an operation (like
8599 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8600 runtime check for overflow isn't necessary. An object in this context means
8601 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8602
8603<h5>Arguments:</h5>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8604<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8605 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8606 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8607 true) or -1 (if false) when the object size is unknown.
8608 The second argument only accepts constants.</p>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8609
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8610<h5>Semantics:</h5>
Nuno Lopes01547b32012-05-09 15:52:43 +0000[diff] [blame]8611<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8612 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8613 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8614 (depending on the <tt>min</tt> argument).</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8615
8616</div>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8617<!-- _______________________________________________________________________ -->
8618<h4>
8619 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8620</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8621
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8622<div>
8623
8624<h5>Syntax:</h5>
8625<pre>
8626 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8627 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8628</pre>
8629
8630<h5>Overview:</h5>
8631<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8632 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8633
8634<h5>Arguments:</h5>
8635<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8636 argument is a value. The second argument is an expected value, this needs to
8637 be a constant value, variables are not allowed.</p>
8638
8639<h5>Semantics:</h5>
8640<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8641</div>
8642
8643</div>
8644
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8645</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8646<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8647<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8648<address>
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8653
8654 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8655 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8656 Last modified: $Date$
8657</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8658
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8659</body>
8660</html>