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gerrit-public.fairphone.software / toolchain / llvm-project / be3d3a66eef6a7480ff315f0011377cc050c5b61 / . / 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>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]260 </ol>
261 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]262 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]263 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]264 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]265 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
266 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
267 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]268 </ol>
269 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]270 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
271 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]272 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
273 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
275 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
276 <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]277 <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]278 </ol>
279 </li>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]280 <li><a href="#spec_arithmetic">Specialised Arithmetic Intrinsics</a>
281 <ol>
282 <li><a href="#fmuladd">'<tt>llvm.fmuladd</tt> Intrinsic</a></li>
283 </ol>
284 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]285 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
286 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]287 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
288 <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]289 </ol>
290 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]291 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]292 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]293 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]294 <ol>
295 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]296 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]297 </ol>
298 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]299 <li><a href="#int_memorymarkers">Memory Use Markers</a>
300 <ol>
Jakub Staszak5fd147f2011-12-04 20:44:25 +0000[diff] [blame]301 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
302 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
303 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
304 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]305 </ol>
306 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]307 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]308 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]309 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]310 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]311 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]312 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]313 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]314 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]315 <li><a href="#int_debugtrap">
316 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]317 <li><a href="#int_stackprotector">
318 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]319 <li><a href="#int_objectsize">
320 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]321 <li><a href="#int_expect">
322 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]323 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]324 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]325 </ol>
326 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]327</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]328
329<div class="doc_author">
330 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
331 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]338<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]339
340<p>This document is a reference manual for the LLVM assembly language. LLVM is
341 a Static Single Assignment (SSA) based representation that provides type
342 safety, low-level operations, flexibility, and the capability of representing
343 'all' high-level languages cleanly. It is the common code representation
344 used throughout all phases of the LLVM compilation strategy.</p>
345
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]346</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]347
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]348<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]349<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]350<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]352<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]354<p>The LLVM code representation is designed to be used in three different forms:
355 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
356 for fast loading by a Just-In-Time compiler), and as a human readable
357 assembly language representation. This allows LLVM to provide a powerful
358 intermediate representation for efficient compiler transformations and
359 analysis, while providing a natural means to debug and visualize the
360 transformations. The three different forms of LLVM are all equivalent. This
361 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]362
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]363<p>The LLVM representation aims to be light-weight and low-level while being
364 expressive, typed, and extensible at the same time. It aims to be a
365 "universal IR" of sorts, by being at a low enough level that high-level ideas
366 may be cleanly mapped to it (similar to how microprocessors are "universal
367 IR's", allowing many source languages to be mapped to them). By providing
368 type information, LLVM can be used as the target of optimizations: for
369 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]370 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]371 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]373<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]374<h4>
375 <a name="wellformed">Well-Formedness</a>
376</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]378<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]379
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]380<p>It is important to note that this document describes 'well formed' LLVM
381 assembly language. There is a difference between what the parser accepts and
382 what is considered 'well formed'. For example, the following instruction is
383 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]384
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]385<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]386%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]387</pre>
388
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]389<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
390 LLVM infrastructure provides a verification pass that may be used to verify
391 that an LLVM module is well formed. This pass is automatically run by the
392 parser after parsing input assembly and by the optimizer before it outputs
393 bitcode. The violations pointed out by the verifier pass indicate bugs in
394 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]396</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]397
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]398</div>
399
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]400<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]402<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]403<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]404<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]405
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]406<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]407
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]408<p>LLVM identifiers come in two basic types: global and local. Global
409 identifiers (functions, global variables) begin with the <tt>'@'</tt>
410 character. Local identifiers (register names, types) begin with
411 the <tt>'%'</tt> character. Additionally, there are three different formats
412 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]413
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]414<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]415 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]416 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
417 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
418 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
419 other characters in their names can be surrounded with quotes. Special
420 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
421 ASCII code for the character in hexadecimal. In this way, any character
422 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]424 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]427 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]428 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]429</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]431<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]432 don't need to worry about name clashes with reserved words, and the set of
433 reserved words may be expanded in the future without penalty. Additionally,
434 unnamed identifiers allow a compiler to quickly come up with a temporary
435 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]437<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]438 languages. There are keywords for different opcodes
439 ('<tt><a href="#i_add">add</a></tt>',
440 '<tt><a href="#i_bitcast">bitcast</a></tt>',
441 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
442 ('<tt><a href="#t_void">void</a></tt>',
443 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
444 reserved words cannot conflict with variable names, because none of them
445 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
447<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]448 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]450<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]456<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]458<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]459%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
461
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]462<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]464<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]465%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
466%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]467%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468</pre>
469
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]470<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
471 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]473<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]475 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]476
477 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]478 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]479
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]480 <li>Unnamed temporaries are numbered sequentially</li>
481</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]482
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]483<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]484 demonstrating instructions, we will follow an instruction with a comment that
485 defines the type and name of value produced. Comments are shown in italic
486 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]487
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]488</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489
490<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]491<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]493<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]494<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]495<h3>
496 <a name="modulestructure">Module Structure</a>
497</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]499<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]501<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
502 translation unit of the input programs. Each module consists of functions,
503 global variables, and symbol table entries. Modules may be combined together
504 with the LLVM linker, which merges function (and global variable)
505 definitions, resolves forward declarations, and merges symbol table
506 entries. Here is an example of the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]507
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]508<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]509<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]510<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]511
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]512<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]513<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]514
515<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]516define i32 @main() { <i>; i32()* </i>&nbsp;
517 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]518 %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]519
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]520 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]521 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]522 <a href="#i_ret">ret</a> i32 0&nbsp;
523}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]524
525<i>; Named metadata</i>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]526!1 = metadata !{i32 42}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]527!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]528</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]530<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]531 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]532 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]533 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]534 "<tt>foo</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]535
Bill Wendling21ee0d22012-03-14 08:07:43 +0000[diff] [blame]536<p>In general, a module is made up of a list of global values (where both
537 functions and global variables are global values). Global values are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]538 represented by a pointer to a memory location (in this case, a pointer to an
539 array of char, and a pointer to a function), and have one of the
540 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]541
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]542</div>
543
544<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]545<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]546 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]547</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]548
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]549<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]550
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]551<p>All Global Variables and Functions have one of the following types of
552 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]553
554<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]555 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]556 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
557 by objects in the current module. In particular, linking code into a
558 module with an private global value may cause the private to be renamed as
559 necessary to avoid collisions. Because the symbol is private to the
560 module, all references can be updated. This doesn't show up in any symbol
561 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]562
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]564 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
565 assembler and evaluated by the linker. Unlike normal strong symbols, they
566 are removed by the linker from the final linked image (executable or
567 dynamic library).</dd>
568
569 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
570 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
571 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
572 linker. The symbols are removed by the linker from the final linked image
573 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]574
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
576 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
577 of the object is not taken. For instance, functions that had an inline
578 definition, but the compiler decided not to inline it. Note,
579 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
580 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
581 visibility. The symbols are removed by the linker from the final linked
582 image (executable or dynamic library).</dd>
583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]585 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]586 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
587 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]588
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]590 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]591 into the object file corresponding to the LLVM module. They exist to
592 allow inlining and other optimizations to take place given knowledge of
593 the definition of the global, which is known to be somewhere outside the
594 module. Globals with <tt>available_externally</tt> linkage are allowed to
595 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
596 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]599 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]600 the same name when linkage occurs. This can be used to implement
601 some forms of inline functions, templates, or other code which must be
602 generated in each translation unit that uses it, but where the body may
603 be overridden with a more definitive definition later. Unreferenced
604 <tt>linkonce</tt> globals are allowed to be discarded. Note that
605 <tt>linkonce</tt> linkage does not actually allow the optimizer to
606 inline the body of this function into callers because it doesn't know if
607 this definition of the function is the definitive definition within the
608 program or whether it will be overridden by a stronger definition.
609 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
610 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]611
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]612 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]613 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
614 <tt>linkonce</tt> linkage, except that unreferenced globals with
615 <tt>weak</tt> linkage may not be discarded. This is used for globals that
616 are declared "weak" in C source code.</dd>
617
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]619 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
620 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
621 global scope.
622 Symbols with "<tt>common</tt>" linkage are merged in the same way as
623 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]624 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]625 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]626 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
627 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]628
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]629
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]631 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]632 pointer to array type. When two global variables with appending linkage
633 are linked together, the two global arrays are appended together. This is
634 the LLVM, typesafe, equivalent of having the system linker append together
635 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]636
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]638 <dd>The semantics of this linkage follow the ELF object file model: the symbol
639 is weak until linked, if not linked, the symbol becomes null instead of
640 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]641
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
643 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644 <dd>Some languages allow differing globals to be merged, such as two functions
645 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]646 that only equivalent globals are ever merged (the "one definition rule"
647 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648 and <tt>weak_odr</tt> linkage types to indicate that the global will only
649 be merged with equivalent globals. These linkage types are otherwise the
650 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]651
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]652 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]653 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]654 visible, meaning that it participates in linkage and can be used to
655 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]656</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658<p>The next two types of linkage are targeted for Microsoft Windows platform
659 only. They are designed to support importing (exporting) symbols from (to)
660 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]661
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]662<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]663 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]664 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]665 or variable via a global pointer to a pointer that is set up by the DLL
666 exporting the symbol. On Microsoft Windows targets, the pointer name is
667 formed by combining <code>__imp_</code> and the function or variable
668 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]669
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]670 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]671 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]672 pointer to a pointer in a DLL, so that it can be referenced with the
673 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
674 name is formed by combining <code>__imp_</code> and the function or
675 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]676</dl>
677
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]678<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
679 another module defined a "<tt>.LC0</tt>" variable and was linked with this
680 one, one of the two would be renamed, preventing a collision. Since
681 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
682 declarations), they are accessible outside of the current module.</p>
683
684<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]685 other than <tt>external</tt>, <tt>dllimport</tt>
686 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]688<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]689 or <tt>weak_odr</tt> linkages.</p>
690
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]691</div>
692
693<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]694<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]696</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]698<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699
700<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]701 and <a href="#i_invoke">invokes</a> can all have an optional calling
702 convention specified for the call. The calling convention of any pair of
703 dynamic caller/callee must match, or the behavior of the program is
704 undefined. The following calling conventions are supported by LLVM, and more
705 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]706
707<dl>
708 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]709 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]710 specified) matches the target C calling conventions. This calling
711 convention supports varargs function calls and tolerates some mismatch in
712 the declared prototype and implemented declaration of the function (as
713 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]714
715 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]716 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]717 (e.g. by passing things in registers). This calling convention allows the
718 target to use whatever tricks it wants to produce fast code for the
719 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]720 (Application Binary Interface).
721 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]722 when this or the GHC convention is used.</a> This calling convention
723 does not support varargs and requires the prototype of all callees to
724 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]725
726 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]727 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]728 as possible under the assumption that the call is not commonly executed.
729 As such, these calls often preserve all registers so that the call does
730 not break any live ranges in the caller side. This calling convention
731 does not support varargs and requires the prototype of all callees to
732 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]733
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]734 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
735 <dd>This calling convention has been implemented specifically for use by the
736 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
737 It passes everything in registers, going to extremes to achieve this by
738 disabling callee save registers. This calling convention should not be
739 used lightly but only for specific situations such as an alternative to
740 the <em>register pinning</em> performance technique often used when
741 implementing functional programming languages.At the moment only X86
742 supports this convention and it has the following limitations:
743 <ul>
744 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
745 floating point types are supported.</li>
746 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
747 6 floating point parameters.</li>
748 </ul>
749 This calling convention supports
750 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
751 requires both the caller and callee are using it.
752 </dd>
753
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]754 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]755 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]756 target-specific calling conventions to be used. Target specific calling
757 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]758</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]759
760<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]761 support Pascal conventions or any other well-known target-independent
762 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]763
764</div>
765
766<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]767<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]769</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]771<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]772
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]773<p>All Global Variables and Functions have one of the following visibility
774 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]775
776<dl>
777 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]778 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 that the declaration is visible to other modules and, in shared libraries,
780 means that the declared entity may be overridden. On Darwin, default
781 visibility means that the declaration is visible to other modules. Default
782 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]783
784 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]785 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]786 object if they are in the same shared object. Usually, hidden visibility
787 indicates that the symbol will not be placed into the dynamic symbol
788 table, so no other module (executable or shared library) can reference it
789 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]790
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]791 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]792 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]793 the dynamic symbol table, but that references within the defining module
794 will bind to the local symbol. That is, the symbol cannot be overridden by
795 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]796</dl>
797
798</div>
799
800<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]801<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]802 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]803</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]805<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]806
807<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]808 it easier to read the IR and make the IR more condensed (particularly when
809 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]811<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]812%mytype = type { %mytype*, i32 }
813</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]815<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]816 "<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]817 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]818
819<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]820 and that you can therefore specify multiple names for the same type. This
821 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
822 uses structural typing, the name is not part of the type. When printing out
823 LLVM IR, the printer will pick <em>one name</em> to render all types of a
824 particular shape. This means that if you have code where two different
825 source types end up having the same LLVM type, that the dumper will sometimes
826 print the "wrong" or unexpected type. This is an important design point and
827 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]828
829</div>
830
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]831<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]832<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]833 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]834</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]835
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]836<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]837
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]838<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]839 instead of run-time. Global variables may optionally be initialized, may
840 have an explicit section to be placed in, and may have an optional explicit
841 alignment specified. A variable may be defined as "thread_local", which
842 means that it will not be shared by threads (each thread will have a
843 separated copy of the variable). A variable may be defined as a global
844 "constant," which indicates that the contents of the variable
845 will <b>never</b> be modified (enabling better optimization, allowing the
846 global data to be placed in the read-only section of an executable, etc).
847 Note that variables that need runtime initialization cannot be marked
848 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]849
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]850<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
851 constant, even if the final definition of the global is not. This capability
852 can be used to enable slightly better optimization of the program, but
853 requires the language definition to guarantee that optimizations based on the
854 'constantness' are valid for the translation units that do not include the
855 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]856
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]857<p>As SSA values, global variables define pointer values that are in scope
858 (i.e. they dominate) all basic blocks in the program. Global variables
859 always define a pointer to their "content" type because they describe a
860 region of memory, and all memory objects in LLVM are accessed through
861 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]862
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]863<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
864 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]865 like this can be merged with other constants if they have the same
866 initializer. Note that a constant with significant address <em>can</em>
867 be merged with a <tt>unnamed_addr</tt> constant, the result being a
868 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]869
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]870<p>A global variable may be declared to reside in a target-specific numbered
871 address space. For targets that support them, address spaces may affect how
872 optimizations are performed and/or what target instructions are used to
873 access the variable. The default address space is zero. The address space
874 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]875
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]876<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]877 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]878
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]879<p>An explicit alignment may be specified for a global, which must be a power
880 of 2. If not present, or if the alignment is set to zero, the alignment of
881 the global is set by the target to whatever it feels convenient. If an
882 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]883 alignment. Targets and optimizers are not allowed to over-align the global
884 if the global has an assigned section. In this case, the extra alignment
885 could be observable: for example, code could assume that the globals are
886 densely packed in their section and try to iterate over them as an array,
887 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]888
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]889<p>For example, the following defines a global in a numbered address space with
890 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]891
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]892<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]893@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]894</pre>
895
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]896</div>
897
898
899<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]900<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]902</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]904<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]905
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]906<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]907 optional <a href="#linkage">linkage type</a>, an optional
908 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]909 <a href="#callingconv">calling convention</a>,
910 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]911 <a href="#paramattrs">parameter attribute</a> for the return type, a function
912 name, a (possibly empty) argument list (each with optional
913 <a href="#paramattrs">parameter attributes</a>), optional
914 <a href="#fnattrs">function attributes</a>, an optional section, an optional
915 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
916 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]917
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]918<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
919 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]920 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]921 <a href="#callingconv">calling convention</a>,
922 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]923 <a href="#paramattrs">parameter attribute</a> for the return type, a function
924 name, a possibly empty list of arguments, an optional alignment, and an
925 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]927<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928 (Control Flow Graph) for the function. Each basic block may optionally start
929 with a label (giving the basic block a symbol table entry), contains a list
930 of instructions, and ends with a <a href="#terminators">terminator</a>
931 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]932
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]933<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]934 executed on entrance to the function, and it is not allowed to have
935 predecessor basic blocks (i.e. there can not be any branches to the entry
936 block of a function). Because the block can have no predecessors, it also
937 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]938
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]939<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]941
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]942<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]943 the alignment is set to zero, the alignment of the function is set by the
944 target to whatever it feels convenient. If an explicit alignment is
945 specified, the function is forced to have at least that much alignment. All
946 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]947
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]948<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]949 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]950
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]951<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]952<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]953define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
955 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
956 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
957 [<a href="#gc">gc</a>] { ... }
958</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]959
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]960</div>
961
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]962<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]963<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]965</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]966
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]967<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]968
969<p>Aliases act as "second name" for the aliasee value (which can be either
970 function, global variable, another alias or bitcast of global value). Aliases
971 may have an optional <a href="#linkage">linkage type</a>, and an
972 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]973
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]974<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]975<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]976@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]977</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]978
979</div>
980
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]981<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]982<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]983 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]984</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]985
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]986<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]988<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]989 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]990 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]991
992<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]993<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]994; Some unnamed metadata nodes, which are referenced by the named metadata.
995!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]996!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]997!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]998; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]999!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1000</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]1001
1002</div>
1003
1004<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1005<h3>
1006 <a name="paramattrs">Parameter Attributes</a>
1007</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1008
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1009<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1010
1011<p>The return type and each parameter of a function type may have a set of
1012 <i>parameter attributes</i> associated with them. Parameter attributes are
1013 used to communicate additional information about the result or parameters of
1014 a function. Parameter attributes are considered to be part of the function,
1015 not of the function type, so functions with different parameter attributes
1016 can have the same function type.</p>
1017
1018<p>Parameter attributes are simple keywords that follow the type specified. If
1019 multiple parameter attributes are needed, they are space separated. For
1020 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1021
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1022<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1023declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1024declare i32 @atoi(i8 zeroext)
1025declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1026</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1027
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1028<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1029 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1030
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1031<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1033<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1035 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1036 should be zero-extended to the extent required by the target's ABI (which
1037 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1038 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1039
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1042 should be sign-extended to the extent required by the target's ABI (which
1043 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1044 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1045
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1046 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1047 <dd>This indicates that this parameter or return value should be treated in a
1048 special target-dependent fashion during while emitting code for a function
1049 call or return (usually, by putting it in a register as opposed to memory,
1050 though some targets use it to distinguish between two different kinds of
1051 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1052
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1053 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1054 <dd><p>This indicates that the pointer parameter should really be passed by
1055 value to the function. The attribute implies that a hidden copy of the
1056 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1057 is made between the caller and the callee, so the callee is unable to
Chris Lattner747482c2012-05-30 00:40:23 +0000[diff] [blame]1058 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059 pointer arguments. It is generally used to pass structs and arrays by
1060 value, but is also valid on pointers to scalars. The copy is considered
1061 to belong to the caller not the callee (for example,
1062 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1063 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1064 values.</p>
1065
1066 <p>The byval attribute also supports specifying an alignment with
1067 the align attribute. It indicates the alignment of the stack slot to
1068 form and the known alignment of the pointer specified to the call site. If
1069 the alignment is not specified, then the code generator makes a
1070 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1071
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1072 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1073 <dd>This indicates that the pointer parameter specifies the address of a
1074 structure that is the return value of the function in the source program.
1075 This pointer must be guaranteed by the caller to be valid: loads and
1076 stores to the structure may be assumed by the callee to not to trap. This
1077 may only be applied to the first parameter. This is not a valid attribute
1078 for return values. </dd>
1079
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1080 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1081 <dd>This indicates that pointer values
1082 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1083 value do not alias pointer values which are not <i>based</i> on it,
1084 ignoring certain "irrelevant" dependencies.
1085 For a call to the parent function, dependencies between memory
1086 references from before or after the call and from those during the call
1087 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1088 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1089 The caller shares the responsibility with the callee for ensuring that
1090 these requirements are met.
1091 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1092 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1093<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1094 Note that this definition of <tt>noalias</tt> is intentionally
1095 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1096 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1097<br>
1098 For function return values, C99's <tt>restrict</tt> is not meaningful,
1099 while LLVM's <tt>noalias</tt> is.
1100 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1101
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1102 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1103 <dd>This indicates that the callee does not make any copies of the pointer
1104 that outlive the callee itself. This is not a valid attribute for return
1105 values.</dd>
1106
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1107 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108 <dd>This indicates that the pointer parameter can be excised using the
1109 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1110 attribute for return values.</dd>
1111</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1112
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1113</div>
1114
1115<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1116<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1117 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1118</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1120<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1121
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1122<p>Each function may specify a garbage collector name, which is simply a
1123 string:</p>
1124
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1125<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1126define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1127</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1128
1129<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1130 collector which will cause the compiler to alter its output in order to
1131 support the named garbage collection algorithm.</p>
1132
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1133</div>
1134
1135<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1136<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1138</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1139
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1140<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1141
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1142<p>Function attributes are set to communicate additional information about a
1143 function. Function attributes are considered to be part of the function, not
1144 of the function type, so functions with different parameter attributes can
1145 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1146
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1147<p>Function attributes are simple keywords that follow the type specified. If
1148 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1149
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1150<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1151define void @f() noinline { ... }
1152define void @f() alwaysinline { ... }
1153define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1154define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1155</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1156
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1157<dl>
Kostya Serebryanya5054ad2012-01-20 17:56:17 +0000[diff] [blame]1158 <dt><tt><b>address_safety</b></tt></dt>
1159 <dd>This attribute indicates that the address safety analysis
1160 is enabled for this function. </dd>
1161
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1162 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1163 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1164 the backend should forcibly align the stack pointer. Specify the
1165 desired alignment, which must be a power of two, in parentheses.
1166
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1167 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1168 <dd>This attribute indicates that the inliner should attempt to inline this
1169 function into callers whenever possible, ignoring any active inlining size
1170 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1171
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1172 <dt><tt><b>nonlazybind</b></tt></dt>
1173 <dd>This attribute suppresses lazy symbol binding for the function. This
1174 may make calls to the function faster, at the cost of extra program
1175 startup time if the function is not called during program startup.</dd>
1176
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1177 <dt><tt><b>inlinehint</b></tt></dt>
1178 <dd>This attribute indicates that the source code contained a hint that inlining
1179 this function is desirable (such as the "inline" keyword in C/C++). It
1180 is just a hint; it imposes no requirements on the inliner.</dd>
1181
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1182 <dt><tt><b>naked</b></tt></dt>
1183 <dd>This attribute disables prologue / epilogue emission for the function.
1184 This can have very system-specific consequences.</dd>
1185
1186 <dt><tt><b>noimplicitfloat</b></tt></dt>
1187 <dd>This attributes disables implicit floating point instructions.</dd>
1188
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This attribute indicates that the inliner should never inline this
1191 function in any situation. This attribute may not be used together with
1192 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1193
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1194 <dt><tt><b>noredzone</b></tt></dt>
1195 <dd>This attribute indicates that the code generator should not use a red
1196 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1197
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1198 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1199 <dd>This function attribute indicates that the function never returns
1200 normally. This produces undefined behavior at runtime if the function
1201 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1202
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This function attribute indicates that the function never returns with an
1205 unwind or exceptional control flow. If the function does unwind, its
1206 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1207
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1208 <dt><tt><b>optsize</b></tt></dt>
1209 <dd>This attribute suggests that optimization passes and code generator passes
1210 make choices that keep the code size of this function low, and otherwise
1211 do optimizations specifically to reduce code size.</dd>
1212
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1213 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1214 <dd>This attribute indicates that the function computes its result (or decides
1215 to unwind an exception) based strictly on its arguments, without
1216 dereferencing any pointer arguments or otherwise accessing any mutable
1217 state (e.g. memory, control registers, etc) visible to caller functions.
1218 It does not write through any pointer arguments
1219 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1220 changes any state visible to callers. This means that it cannot unwind
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1221 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1222
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1223 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1224 <dd>This attribute indicates that the function does not write through any
1225 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1226 arguments) or otherwise modify any state (e.g. memory, control registers,
1227 etc) visible to caller functions. It may dereference pointer arguments
1228 and read state that may be set in the caller. A readonly function always
1229 returns the same value (or unwinds an exception identically) when called
1230 with the same set of arguments and global state. It cannot unwind an
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1231 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1232
Bill Wendlingb437ab82011-12-05 21:27:54 +0000[diff] [blame]1233 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1234 <dd>This attribute indicates that this function can return twice. The
1235 C <code>setjmp</code> is an example of such a function. The compiler
1236 disables some optimizations (like tail calls) in the caller of these
1237 functions.</dd>
1238
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1239 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1240 <dd>This attribute indicates that the function should emit a stack smashing
1241 protector. It is in the form of a "canary"&mdash;a random value placed on
1242 the stack before the local variables that's checked upon return from the
1243 function to see if it has been overwritten. A heuristic is used to
1244 determine if a function needs stack protectors or not.<br>
1245<br>
1246 If a function that has an <tt>ssp</tt> attribute is inlined into a
1247 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1248 function will have an <tt>ssp</tt> attribute.</dd>
1249
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1250 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1251 <dd>This attribute indicates that the function should <em>always</em> emit a
1252 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1253 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1254<br>
1255 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1256 function that doesn't have an <tt>sspreq</tt> attribute or which has
1257 an <tt>ssp</tt> attribute, then the resulting function will have
1258 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1259
1260 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1261 <dd>This attribute indicates that the ABI being targeted requires that
1262 an unwind table entry be produce for this function even if we can
1263 show that no exceptions passes by it. This is normally the case for
1264 the ELF x86-64 abi, but it can be disabled for some compilation
1265 units.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1266</dl>
1267
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1268</div>
1269
1270<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1271<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1272 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1273</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1274
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1275<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1276
1277<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1278 the GCC "file scope inline asm" blocks. These blocks are internally
1279 concatenated by LLVM and treated as a single unit, but may be separated in
1280 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1281
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1282<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1283module asm "inline asm code goes here"
1284module asm "more can go here"
1285</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1286
1287<p>The strings can contain any character by escaping non-printable characters.
1288 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]1289 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1290
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1291<p>The inline asm code is simply printed to the machine code .s file when
1292 assembly code is generated.</p>
1293
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1294</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1295
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1296<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1297<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1298 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1299</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1300
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1301<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1302
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1303<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304 data is to be laid out in memory. The syntax for the data layout is
1305 simply:</p>
1306
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1307<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1308target datalayout = "<i>layout specification</i>"
1309</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1310
1311<p>The <i>layout specification</i> consists of a list of specifications
1312 separated by the minus sign character ('-'). Each specification starts with
1313 a letter and may include other information after the letter to define some
1314 aspect of the data layout. The specifications accepted are as follows:</p>
1315
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1316<dl>
1317 <dt><tt>E</tt></dt>
1318 <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]1319 bits with the most significance have the lowest address location.</dd>
1320
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1321 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1322 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1323 the bits with the least significance have the lowest address
1324 location.</dd>
1325
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1326 <dt><tt>S<i>size</i></tt></dt>
1327 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1328 of stack variables is limited to the natural stack alignment to avoid
1329 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1330 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1331 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1332
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1334 <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]1335 <i>preferred</i> alignments. All sizes are in bits. Specifying
1336 the <i>pref</i> alignment is optional. If omitted, the
1337 preceding <tt>:</tt> should be omitted too.</dd>
1338
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1339 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1340 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1341 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1342
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1343 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1344 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1345 <i>size</i>.</dd>
1346
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1347 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1348 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1349 <i>size</i>. Only values of <i>size</i> that are supported by the target
1350 will work. 32 (float) and 64 (double) are supported on all targets;
1351 80 or 128 (different flavors of long double) are also supported on some
1352 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1354 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1355 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1356 <i>size</i>.</dd>
1357
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1358 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1359 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1360 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1361
1362 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1363 <dd>This specifies a set of native integer widths for the target CPU
1364 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1365 "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]1366 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1367 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1368</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1369
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1370<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1371 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1372 specifications in the <tt>datalayout</tt> keyword. The default specifications
1373 are given in this list:</p>
1374
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1375<ul>
1376 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1377 <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]1378 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1379 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1380 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1381 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1382 <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]1383 alignment of 64-bits</li>
1384 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1385 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1386 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1387 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1388 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1389 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1390</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391
1392<p>When LLVM is determining the alignment for a given type, it uses the
1393 following rules:</p>
1394
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1395<ol>
1396 <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]1397 specification is used.</li>
1398
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1399 <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]1400 smallest integer type that is larger than the bitwidth of the sought type
1401 is used. If none of the specifications are larger than the bitwidth then
1402 the the largest integer type is used. For example, given the default
1403 specifications above, the i7 type will use the alignment of i8 (next
1404 largest) while both i65 and i256 will use the alignment of i64 (largest
1405 specified).</li>
1406
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1407 <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]1408 largest vector type that is smaller than the sought vector type will be
1409 used as a fall back. This happens because &lt;128 x double&gt; can be
1410 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1411</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1412
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1413<p>The function of the data layout string may not be what you expect. Notably,
1414 this is not a specification from the frontend of what alignment the code
1415 generator should use.</p>
1416
1417<p>Instead, if specified, the target data layout is required to match what the
1418 ultimate <em>code generator</em> expects. This string is used by the
1419 mid-level optimizers to
1420 improve code, and this only works if it matches what the ultimate code
1421 generator uses. If you would like to generate IR that does not embed this
1422 target-specific detail into the IR, then you don't have to specify the
1423 string. This will disable some optimizations that require precise layout
1424 information, but this also prevents those optimizations from introducing
1425 target specificity into the IR.</p>
1426
1427
1428
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1429</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1430
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1432<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1433 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1434</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1435
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1436<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1437
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1438<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1439with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1440is undefined. Pointer values are associated with address ranges
1441according to the following rules:</p>
1442
1443<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1444 <li>A pointer value is associated with the addresses associated with
1445 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1446 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1447 range of the variable's storage.</li>
1448 <li>The result value of an allocation instruction is associated with
1449 the address range of the allocated storage.</li>
1450 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1451 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1452 <li>An integer constant other than zero or a pointer value returned
1453 from a function not defined within LLVM may be associated with address
1454 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1455 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1456 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1457</ul>
1458
1459<p>A pointer value is <i>based</i> on another pointer value according
1460 to the following rules:</p>
1461
1462<ul>
1463 <li>A pointer value formed from a
1464 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1465 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1466 <li>The result value of a
1467 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1468 of the <tt>bitcast</tt>.</li>
1469 <li>A pointer value formed by an
1470 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1471 pointer values that contribute (directly or indirectly) to the
1472 computation of the pointer's value.</li>
1473 <li>The "<i>based</i> on" relationship is transitive.</li>
1474</ul>
1475
1476<p>Note that this definition of <i>"based"</i> is intentionally
1477 similar to the definition of <i>"based"</i> in C99, though it is
1478 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1479
1480<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1481<tt><a href="#i_load">load</a></tt> merely indicates the size and
1482alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1483interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1484<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1485and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1486
1487<p>Consequently, type-based alias analysis, aka TBAA, aka
1488<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1489LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1490additional information which specialized optimization passes may use
1491to implement type-based alias analysis.</p>
1492
1493</div>
1494
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1495<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1496<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1497 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1498</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1499
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1500<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1501
1502<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1503href="#i_store"><tt>store</tt></a>s, and <a
1504href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1505The optimizers must not change the number of volatile operations or change their
1506order of execution relative to other volatile operations. The optimizers
1507<i>may</i> change the order of volatile operations relative to non-volatile
1508operations. This is not Java's "volatile" and has no cross-thread
1509synchronization behavior.</p>
1510
1511</div>
1512
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1513<!-- ======================================================================= -->
1514<h3>
1515 <a name="memmodel">Memory Model for Concurrent Operations</a>
1516</h3>
1517
1518<div>
1519
1520<p>The LLVM IR does not define any way to start parallel threads of execution
1521or to register signal handlers. Nonetheless, there are platform-specific
1522ways to create them, and we define LLVM IR's behavior in their presence. This
1523model is inspired by the C++0x memory model.</p>
1524
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1525<p>For a more informal introduction to this model, see the
1526<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1527
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1528<p>We define a <i>happens-before</i> partial order as the least partial order
1529that</p>
1530<ul>
1531 <li>Is a superset of single-thread program order, and</li>
1532 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1533 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1534 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1535 creation, thread joining, etc., and by atomic instructions.
1536 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1537 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1538</ul>
1539
1540<p>Note that program order does not introduce <i>happens-before</i> edges
1541between a thread and signals executing inside that thread.</p>
1542
1543<p>Every (defined) read operation (load instructions, memcpy, atomic
1544loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1545(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1546stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1547initialized globals are considered to have a write of the initializer which is
1548atomic and happens before any other read or write of the memory in question.
1549For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1550any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1551
1552<ul>
1553 <li>If <var>write<sub>1</sub></var> happens before
1554 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1555 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1556 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1557 <li>If <var>R<sub>byte</sub></var> happens before
1558 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1559 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1560</ul>
1561
1562<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1563<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1564 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1565 is supposed to give guarantees which can support
1566 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1567 addresses which do not behave like normal memory. It does not generally
1568 provide cross-thread synchronization.)
1569 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1570 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1571 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1572 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1573 <var>R<sub>byte</sub></var> returns the value written by that
1574 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1575 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1576 <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]1577 values written. See the <a href="#ordering">Atomic Memory Ordering
1578 Constraints</a> section for additional constraints on how the choice
1579 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1580 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1581</ul>
1582
1583<p><var>R</var> returns the value composed of the series of bytes it read.
1584This implies that some bytes within the value may be <tt>undef</tt>
1585<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1586defines the semantics of the operation; it doesn't mean that targets will
1587emit more than one instruction to read the series of bytes.</p>
1588
1589<p>Note that in cases where none of the atomic intrinsics are used, this model
1590places only one restriction on IR transformations on top of what is required
1591for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1592otherwise be stored is not allowed in general. (Specifically, in the case
1593where another thread might write to and read from an address, introducing a
1594store can change a load that may see exactly one write into a load that may
1595see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1596
1597<!-- FIXME: This model assumes all targets where concurrency is relevant have
1598a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1599none of the backends currently in the tree fall into this category; however,
1600there might be targets which care. If there are, we want a paragraph
1601like the following:
1602
1603Targets may specify that stores narrower than a certain width are not
1604available; on such a target, for the purposes of this model, treat any
1605non-atomic write with an alignment or width less than the minimum width
1606as if it writes to the relevant surrounding bytes.
1607-->
1608
1609</div>
1610
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1611<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1612<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1613 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1614</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1615
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1616<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1617
1618<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1619<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1620<a href="#i_fence"><code>fence</code></a>,
1621<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1622<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1623that determines which other atomic instructions on the same address they
1624<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1625but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1626check those specs (see spec references in the
Nick Lewycky75499f52012-01-23 08:47:21 +0000[diff] [blame]1627<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1628<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1629treat these orderings somewhat differently since they don't take an address.
1630See that instruction's documentation for details.</p>
1631
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1632<p>For a simpler introduction to the ordering constraints, see the
1633<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1634
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1635<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1636<dt><code>unordered</code></dt>
1637<dd>The set of values that can be read is governed by the happens-before
1638partial order. A value cannot be read unless some operation wrote it.
1639This is intended to provide a guarantee strong enough to model Java's
1640non-volatile shared variables. This ordering cannot be specified for
1641read-modify-write operations; it is not strong enough to make them atomic
1642in any interesting way.</dd>
1643<dt><code>monotonic</code></dt>
1644<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1645total order for modifications by <code>monotonic</code> operations on each
1646address. All modification orders must be compatible with the happens-before
1647order. There is no guarantee that the modification orders can be combined to
1648a global total order for the whole program (and this often will not be
1649possible). The read in an atomic read-modify-write operation
1650(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1651<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1652reads the value in the modification order immediately before the value it
1653writes. If one atomic read happens before another atomic read of the same
1654address, the later read must see the same value or a later value in the
1655address's modification order. This disallows reordering of
1656<code>monotonic</code> (or stronger) operations on the same address. If an
1657address is written <code>monotonic</code>ally by one thread, and other threads
1658<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1659eventually see the write. This corresponds to the C++0x/C1x
1660<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1661<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1662<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1663a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1664operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1665<dt><code>release</code></dt>
1666<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1667writes a value which is subsequently read by an <code>acquire</code> operation,
1668it <i>synchronizes-with</i> that operation. (This isn't a complete
1669description; see the C++0x definition of a release sequence.) This corresponds
1670to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1671<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1672<code>acquire</code> and <code>release</code> operation on its address.
1673This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1674<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1675<dd>In addition to the guarantees of <code>acq_rel</code>
1676(<code>acquire</code> for an operation which only reads, <code>release</code>
1677for an operation which only writes), there is a global total order on all
1678sequentially-consistent operations on all addresses, which is consistent with
1679the <i>happens-before</i> partial order and with the modification orders of
1680all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1681preceding write to the same address in this global order. This corresponds
1682to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1683</dl>
1684
1685<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1686it only <i>synchronizes with</i> or participates in modification and seq_cst
1687total orderings with other operations running in the same thread (for example,
1688in signal handlers).</p>
1689
1690</div>
1691
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1692</div>
1693
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1694<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1695<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1696<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1697
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1698<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1699
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1700<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1701 intermediate representation. Being typed enables a number of optimizations
1702 to be performed on the intermediate representation directly, without having
1703 to do extra analyses on the side before the transformation. A strong type
1704 system makes it easier to read the generated code and enables novel analyses
1705 and transformations that are not feasible to perform on normal three address
1706 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1707
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1708<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1709<h3>
1710 <a name="t_classifications">Type Classifications</a>
1711</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1712
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1713<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1714
1715<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1716
1717<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1718 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1719 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1720 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1721 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1722 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
1724 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1725 <td><a href="#t_floating">floating point</a></td>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1726 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1727 </tr>
1728 <tr>
1729 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1730 <td><a href="#t_integer">integer</a>,
1731 <a href="#t_floating">floating point</a>,
1732 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1733 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1734 <a href="#t_struct">structure</a>,
1735 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1736 <a href="#t_label">label</a>,
1737 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1738 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1739 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1740 <tr>
1741 <td><a href="#t_primitive">primitive</a></td>
1742 <td><a href="#t_label">label</a>,
1743 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1744 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1745 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1746 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1747 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1748 </tr>
1749 <tr>
1750 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1751 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1752 <a href="#t_function">function</a>,
1753 <a href="#t_pointer">pointer</a>,
1754 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1755 <a href="#t_vector">vector</a>,
1756 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1757 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1758 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1759 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1760</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1761
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1762<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1763 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1764 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1765
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1766</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1768<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1769<h3>
1770 <a name="t_primitive">Primitive Types</a>
1771</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1772
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1773<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1774
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1775<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1776 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1777
1778<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1779<h4>
1780 <a name="t_integer">Integer Type</a>
1781</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1782
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1783<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1784
1785<h5>Overview:</h5>
1786<p>The integer type is a very simple type that simply specifies an arbitrary
1787 bit width for the integer type desired. Any bit width from 1 bit to
1788 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1789
1790<h5>Syntax:</h5>
1791<pre>
1792 iN
1793</pre>
1794
1795<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1796 value.</p>
1797
1798<h5>Examples:</h5>
1799<table class="layout">
1800 <tr class="layout">
1801 <td class="left"><tt>i1</tt></td>
1802 <td class="left">a single-bit integer.</td>
1803 </tr>
1804 <tr class="layout">
1805 <td class="left"><tt>i32</tt></td>
1806 <td class="left">a 32-bit integer.</td>
1807 </tr>
1808 <tr class="layout">
1809 <td class="left"><tt>i1942652</tt></td>
1810 <td class="left">a really big integer of over 1 million bits.</td>
1811 </tr>
1812</table>
1813
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1814</div>
1815
1816<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1817<h4>
1818 <a name="t_floating">Floating Point Types</a>
1819</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1820
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1821<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1822
1823<table>
1824 <tbody>
1825 <tr><th>Type</th><th>Description</th></tr>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1826 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1827 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1828 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1829 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1830 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1831 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1832 </tbody>
1833</table>
1834
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1835</div>
1836
1837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1838<h4>
1839 <a name="t_x86mmx">X86mmx Type</a>
1840</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1842<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1843
1844<h5>Overview:</h5>
1845<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>
1846
1847<h5>Syntax:</h5>
1848<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1849 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1850</pre>
1851
1852</div>
1853
1854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1855<h4>
1856 <a name="t_void">Void Type</a>
1857</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1858
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1859<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1861<h5>Overview:</h5>
1862<p>The void type does not represent any value and has no size.</p>
1863
1864<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1865<pre>
1866 void
1867</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_label">Label Type</a>
1874</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1875
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1877
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1878<h5>Overview:</h5>
1879<p>The label type represents code labels.</p>
1880
1881<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1882<pre>
1883 label
1884</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1885
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1886</div>
1887
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1888<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1889<h4>
1890 <a name="t_metadata">Metadata Type</a>
1891</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1892
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1893<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1894
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1895<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1896<p>The metadata type represents embedded metadata. No derived types may be
1897 created from metadata except for <a href="#t_function">function</a>
1898 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1899
1900<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1901<pre>
1902 metadata
1903</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1904
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1905</div>
1906
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1907</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1908
1909<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1910<h3>
1911 <a name="t_derived">Derived Types</a>
1912</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1913
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1914<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1916<p>The real power in LLVM comes from the derived types in the system. This is
1917 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1918 useful types. Each of these types contain one or more element types which
1919 may be a primitive type, or another derived type. For example, it is
1920 possible to have a two dimensional array, using an array as the element type
1921 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1922
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1924<h4>
1925 <a name="t_aggregate">Aggregate Types</a>
1926</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1927
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1928<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1929
1930<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands9aaec152011-12-14 15:44:20 +0000[diff] [blame]1931 member types. <a href="#t_array">Arrays</a> and
1932 <a href="#t_struct">structs</a> are aggregate types.
1933 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1934
1935</div>
1936
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1937<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1938<h4>
1939 <a name="t_array">Array Type</a>
1940</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1941
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1942<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1943
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1944<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1945<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1946 sequentially in memory. The array type requires a size (number of elements)
1947 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1948
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1949<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1950<pre>
1951 [&lt;# elements&gt; x &lt;elementtype&gt;]
1952</pre>
1953
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1954<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1955 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1956
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1957<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1958<table class="layout">
1959 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1960 <td class="left"><tt>[40 x i32]</tt></td>
1961 <td class="left">Array of 40 32-bit integer values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[41 x i32]</tt></td>
1965 <td class="left">Array of 41 32-bit integer values.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>[4 x i8]</tt></td>
1969 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1970 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1971</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1972<p>Here are some examples of multidimensional arrays:</p>
1973<table class="layout">
1974 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1975 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1976 <td class="left">3x4 array of 32-bit integer values.</td>
1977 </tr>
1978 <tr class="layout">
1979 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1980 <td class="left">12x10 array of single precision floating point values.</td>
1981 </tr>
1982 <tr class="layout">
1983 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1984 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1985 </tr>
1986</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1987
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1988<p>There is no restriction on indexing beyond the end of the array implied by
1989 a static type (though there are restrictions on indexing beyond the bounds
1990 of an allocated object in some cases). This means that single-dimension
1991 'variable sized array' addressing can be implemented in LLVM with a zero
1992 length array type. An implementation of 'pascal style arrays' in LLVM could
1993 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1995</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1996
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1997<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1998<h4>
1999 <a name="t_function">Function Type</a>
2000</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2001
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2002<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2003
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2004<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2005<p>The function type can be thought of as a function signature. It consists of
2006 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]2007 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]2008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2009<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2010<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2011 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2012</pre>
2013
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2014<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]2015 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2016 which indicates that the function takes a variable number of arguments.
2017 Variable argument functions can access their arguments with
2018 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2019 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2020 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2021
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2022<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2023<table class="layout">
2024 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2025 <td class="left"><tt>i32 (i32)</tt></td>
2026 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2027 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2028 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2029 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2030 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2031 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2032 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2033 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2034 </td>
2035 </tr><tr class="layout">
2036 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2037 <td class="left">A vararg function that takes at least one
2038 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2039 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2040 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2041 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2042 </tr><tr class="layout">
2043 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2044 <td class="left">A function taking an <tt>i32</tt>, returning a
2045 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2046 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2047 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2048</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2049
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2050</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2051
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2052<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2053<h4>
2054 <a name="t_struct">Structure Type</a>
2055</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2056
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2057<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2058
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2059<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2060<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2061 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]2062
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2063<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2064 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2065 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2066 Structures in registers are accessed using the
2067 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2068 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2069
2070<p>Structures may optionally be "packed" structures, which indicate that the
2071 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2072 the elements. In non-packed structs, padding between field types is inserted
2073 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2074 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2075
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2076<p>Structures can either be "literal" or "identified". A literal structure is
2077 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2078 types are always defined at the top level with a name. Literal types are
2079 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2080 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]2081 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2082</p>
2083
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2084<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2085<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2086 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2087 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2088</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2089
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2090<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2091<table class="layout">
2092 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2093 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2094 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2095 </tr>
2096 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2097 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2098 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2099 second element is a <a href="#t_pointer">pointer</a> to a
2100 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2101 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2102 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2103 <tr class="layout">
2104 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2105 <td class="left">A packed struct known to be 5 bytes in size.</td>
2106 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2107</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2108
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2109</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2110
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2111<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2112<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2113 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2114</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2115
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2116<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2117
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2118<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2119<p>Opaque structure types are used to represent named structure types that do
2120 not have a body specified. This corresponds (for example) to the C notion of
2121 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2122
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2123<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2124<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2125 %X = type opaque
2126 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2127</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2128
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2129<h5>Examples:</h5>
2130<table class="layout">
2131 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2132 <td class="left"><tt>opaque</tt></td>
2133 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2134 </tr>
2135</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2136
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2137</div>
2138
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2139
2140
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2141<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2142<h4>
2143 <a name="t_pointer">Pointer Type</a>
2144</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2145
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2146<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2147
2148<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2149<p>The pointer type is used to specify memory locations.
2150 Pointers are commonly used to reference objects in memory.</p>
2151
2152<p>Pointer types may have an optional address space attribute defining the
2153 numbered address space where the pointed-to object resides. The default
2154 address space is number zero. The semantics of non-zero address
2155 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2156
2157<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2158 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2159
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2160<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2161<pre>
2162 &lt;type&gt; *
2163</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2164
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2165<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2166<table class="layout">
2167 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2168 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2169 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2170 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2171 </tr>
2172 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2173 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2174 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2175 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2176 <tt>i32</tt>.</td>
2177 </tr>
2178 <tr class="layout">
2179 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2180 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2181 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2182 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2183</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2184
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2185</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2186
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2187<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2188<h4>
2189 <a name="t_vector">Vector Type</a>
2190</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2191
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2192<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2193
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2194<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2195<p>A vector type is a simple derived type that represents a vector of elements.
2196 Vector types are used when multiple primitive data are operated in parallel
2197 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2198 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2199 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2200
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2201<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2202<pre>
2203 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2204</pre>
2205
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2206<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2207 may be any integer or floating point type, or a pointer to these types.
2208 Vectors of size zero are not allowed. </p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2209
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2210<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2211<table class="layout">
2212 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2213 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2214 <td class="left">Vector of 4 32-bit integer values.</td>
2215 </tr>
2216 <tr class="layout">
2217 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2218 <td class="left">Vector of 8 32-bit floating-point values.</td>
2219 </tr>
2220 <tr class="layout">
2221 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2222 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2223 </tr>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2224 <tr class="layout">
2225 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2226 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2227 </tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2228</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2229
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2230</div>
2231
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2232</div>
2233
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2234</div>
2235
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2236<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2237<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2238<!-- *********************************************************************** -->
2239
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2240<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2241
2242<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2243 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2244
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2245<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2246<h3>
2247 <a name="simpleconstants">Simple Constants</a>
2248</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2249
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2250<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2251
2252<dl>
2253 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2254 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2255 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2256
2257 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2258 <dd>Standard integers (such as '4') are constants of
2259 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2260 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2261
2262 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2263 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2264 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2265 notation (see below). The assembler requires the exact decimal value of a
2266 floating-point constant. For example, the assembler accepts 1.25 but
2267 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2268 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2269
2270 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2271 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2272 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2273</dl>
2274
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2275<p>The one non-intuitive notation for constants is the hexadecimal form of
2276 floating point constants. For example, the form '<tt>double
2277 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2278 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2279 constants are required (and the only time that they are generated by the
2280 disassembler) is when a floating point constant must be emitted but it cannot
2281 be represented as a decimal floating point number in a reasonable number of
2282 digits. For example, NaN's, infinities, and other special values are
2283 represented in their IEEE hexadecimal format so that assembly and disassembly
2284 do not cause any bits to change in the constants.</p>
2285
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2286<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2287 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2288 representation for double); half and float values must, however, be exactly
2289 representable as IEE754 half and single precision, respectively.
2290 Hexadecimal format is always used
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2291 for long double, and there are three forms of long double. The 80-bit format
2292 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2293 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2294 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2295 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2296 currently supported target uses this format. Long doubles will only work if
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]2297 they match the long double format on your target. The IEEE 16-bit format
2298 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2299 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2300
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2301<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2302</div>
2303
2304<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2305<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2306<a name="aggregateconstants"></a> <!-- old anchor -->
2307<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2308</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2309
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2310<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2311
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2312<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2313 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2314
2315<dl>
2316 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2317 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2318 type definitions (a comma separated list of elements, surrounded by braces
2319 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2320 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2321 Structure constants must have <a href="#t_struct">structure type</a>, and
2322 the number and types of elements must match those specified by the
2323 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2324
2325 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2326 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2327 definitions (a comma separated list of elements, surrounded by square
2328 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2329 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2330 the number and types of elements must match those specified by the
2331 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2332
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2333 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2334 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2335 definitions (a comma separated list of elements, surrounded by
2336 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2337 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2338 have <a href="#t_vector">vector type</a>, and the number and types of
2339 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2340
2341 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2342 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2343 value to zero of <em>any</em> type, including scalar and
2344 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2345 This is often used to avoid having to print large zero initializers
2346 (e.g. for large arrays) and is always exactly equivalent to using explicit
2347 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2348
2349 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2350 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2351 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2352 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2353 be interpreted as part of the instruction stream, metadata is a place to
2354 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2355</dl>
2356
2357</div>
2358
2359<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2360<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2361 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2362</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2364<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2365
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2366<p>The addresses of <a href="#globalvars">global variables</a>
2367 and <a href="#functionstructure">functions</a> are always implicitly valid
2368 (link-time) constants. These constants are explicitly referenced when
2369 the <a href="#identifiers">identifier for the global</a> is used and always
2370 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2371 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2372
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2373<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2374@X = global i32 17
2375@Y = global i32 42
2376@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2377</pre>
2378
2379</div>
2380
2381<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2382<h3>
2383 <a name="undefvalues">Undefined Values</a>
2384</h3>
2385
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2386<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2387
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2388<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]2389 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2390 Undefined values may be of any type (other than '<tt>label</tt>'
2391 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2392
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2393<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2394 program is well defined no matter what value is used. This gives the
2395 compiler more freedom to optimize. Here are some examples of (potentially
2396 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2397
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2398
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2399<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2400 %A = add %X, undef
2401 %B = sub %X, undef
2402 %C = xor %X, undef
2403Safe:
2404 %A = undef
2405 %B = undef
2406 %C = undef
2407</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2408
2409<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]2410 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]2411
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2412<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2413 %A = or %X, undef
2414 %B = and %X, undef
2415Safe:
2416 %A = -1
2417 %B = 0
2418Unsafe:
2419 %A = undef
2420 %B = undef
2421</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2422
2423<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2424 For example, if <tt>%X</tt> has a zero bit, then the output of the
2425 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2426 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2427 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2428 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2429 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2430 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2431 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = select undef, %X, %Y
2435 %B = select undef, 42, %Y
2436 %C = select %X, %Y, undef
2437Safe:
2438 %A = %X (or %Y)
2439 %B = 42 (or %Y)
2440 %C = %Y
2441Unsafe:
2442 %A = undef
2443 %B = undef
2444 %C = undef
2445</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2446
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2447<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2448 branch) conditions can go <em>either way</em>, but they have to come from one
2449 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2450 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2451 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2452 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2453 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2454 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2455
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2456<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2457 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2458
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2459 %B = undef
2460 %C = xor %B, %B
2461
2462 %D = undef
2463 %E = icmp lt %D, 4
2464 %F = icmp gte %D, 4
2465
2466Safe:
2467 %A = undef
2468 %B = undef
2469 %C = undef
2470 %D = undef
2471 %E = undef
2472 %F = undef
2473</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2474
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2475<p>This example points out that two '<tt>undef</tt>' operands are not
2476 necessarily the same. This can be surprising to people (and also matches C
2477 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2478 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2479 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2480 its value over its "live range". This is true because the variable doesn't
2481 actually <em>have a live range</em>. Instead, the value is logically read
2482 from arbitrary registers that happen to be around when needed, so the value
2483 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2484 need to have the same semantics or the core LLVM "replace all uses with"
2485 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2486
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2487<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2488 %A = fdiv undef, %X
2489 %B = fdiv %X, undef
2490Safe:
2491 %A = undef
2492b: unreachable
2493</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2494
2495<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2496 value</em> and <em>undefined behavior</em>. An undefined value (like
2497 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2498 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2499 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2500 defined on SNaN's. However, in the second example, we can make a more
2501 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2502 arbitrary value, we are allowed to assume that it could be zero. Since a
2503 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2504 the operation does not execute at all. This allows us to delete the divide and
2505 all code after it. Because the undefined operation "can't happen", the
2506 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2507
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2508<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2509a: store undef -> %X
2510b: store %X -> undef
2511Safe:
2512a: &lt;deleted&gt;
2513b: unreachable
2514</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2515
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2516<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2517 undefined value can be assumed to not have any effect; we can assume that the
2518 value is overwritten with bits that happen to match what was already there.
2519 However, a store <em>to</em> an undefined location could clobber arbitrary
2520 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2521
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2522</div>
2523
2524<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2525<h3>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2526 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2527</h3>
2528
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2529<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2530
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2531<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2532 they also represent the fact that an instruction or constant expression which
2533 cannot evoke side effects has nevertheless detected a condition which results
2534 in undefined behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2535
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2536<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]2537 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2538 <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]2539
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2540<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2541
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2542<ul>
2543<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2544 their operands.</li>
2545
2546<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2547 to their dynamic predecessor basic block.</li>
2548
2549<li>Function arguments depend on the corresponding actual argument values in
2550 the dynamic callers of their functions.</li>
2551
2552<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2553 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2554 control back to them.</li>
2555
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2556<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]2557 <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]2558 or exception-throwing call instructions that dynamically transfer control
2559 back to them.</li>
2560
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2561<li>Non-volatile loads and stores depend on the most recent stores to all of the
2562 referenced memory addresses, following the order in the IR
2563 (including loads and stores implied by intrinsics such as
2564 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2565
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2566<!-- TODO: In the case of multiple threads, this only applies if the store
2567 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2568
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2569<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2570
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2571<li>An instruction with externally visible side effects depends on the most
2572 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2573 the order in the IR. (This includes
2574 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2575
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2576<li>An instruction <i>control-depends</i> on a
2577 <a href="#terminators">terminator instruction</a>
2578 if the terminator instruction has multiple successors and the instruction
2579 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2580 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2581
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2582<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2583 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2584 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2585 successor.</li>
2586
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2587<li>Dependence is transitive.</li>
2588
2589</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2590
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2591<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2592 with the additional affect that any instruction which has a <i>dependence</i>
2593 on a poison value has undefined behavior.</p>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2594
2595<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2596
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2597<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2598entry:
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2599 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2600 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2601 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2602 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2603
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2604 store i32 %poison, i32* @g ; Poison value stored to memory.
2605 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2606
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2607 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2608
2609 %narrowaddr = bitcast i32* @g to i16*
2610 %wideaddr = bitcast i32* @g to i64*
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2611 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2612 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2613
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2614 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2615 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2616
2617true:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2618 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2619 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2620 br label %end
2621
2622end:
2623 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2624 ; Both edges into this PHI are
2625 ; control-dependent on %cmp, so this
2626 ; always results in a poison value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2627
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2628 store volatile i32 0, i32* @g ; This would depend on the store in %true
2629 ; if %cmp is true, or the store in %entry
2630 ; otherwise, so this is undefined behavior.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2631
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2632 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2633 ; The same branch again, but this time the
2634 ; true block doesn't have side effects.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2635
2636second_true:
2637 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2638 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2639
2640second_end:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2641 store volatile i32 0, i32* @g ; This time, the instruction always depends
2642 ; on the store in %end. Also, it is
2643 ; control-equivalent to %end, so this is
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2644 ; well-defined (ignoring earlier undefined
2645 ; behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2646</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2647
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2648</div>
2649
2650<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2651<h3>
2652 <a name="blockaddress">Addresses of Basic Blocks</a>
2653</h3>
2654
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2655<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2656
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2657<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2658
2659<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2660 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2661 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2662
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2663<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2664 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2665 comparisons against null. Pointer equality tests between labels addresses
2666 results in undefined behavior &mdash; though, again, comparison against null
2667 is ok, and no label is equal to the null pointer. This may be passed around
2668 as an opaque pointer sized value as long as the bits are not inspected. This
2669 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2670 long as the original value is reconstituted before the <tt>indirectbr</tt>
2671 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2672
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2673<p>Finally, some targets may provide defined semantics when using the value as
2674 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2675
2676</div>
2677
2678
2679<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2680<h3>
2681 <a name="constantexprs">Constant Expressions</a>
2682</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2683
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2684<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2685
2686<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2687 to be used as constants. Constant expressions may be of
2688 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2689 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2690 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2691
2692<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2693 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2694 <dd>Truncate a constant to another type. The bit size of CST must be larger
2695 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2696
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2697 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2698 <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]2699 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2700
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2701 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2702 <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]2703 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2704
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2705 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2706 <dd>Truncate a floating point constant to another floating point type. The
2707 size of CST must be larger than the size of TYPE. Both types must be
2708 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2709
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2710 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2711 <dd>Floating point extend a constant to another type. The size of CST must be
2712 smaller or equal to the size of TYPE. Both types must be floating
2713 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2714
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2715 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2716 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2717 constant. TYPE must be a scalar or vector integer type. CST must be of
2718 scalar or vector floating point type. Both CST and TYPE must be scalars,
2719 or vectors of the same number of elements. If the value won't fit in the
2720 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2721
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2722 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2723 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2724 constant. TYPE must be a scalar or vector integer type. CST must be of
2725 scalar or vector floating point type. Both CST and TYPE must be scalars,
2726 or vectors of the same number of elements. If the value won't fit in the
2727 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2728
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2729 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2730 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2731 constant. TYPE must be a scalar or vector floating point type. CST must be
2732 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2733 vectors of the same number of elements. If the value won't fit in the
2734 floating point type, the results are undefined.</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>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2737 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2738 constant. TYPE must be a scalar or vector floating point type. CST must be
2739 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2740 vectors of the same number of elements. If the value won't fit in the
2741 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2742
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2743 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2744 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2745 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2746 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2747 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2748
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2750 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2751 type. CST must be of integer type. The CST value is zero extended,
2752 truncated, or unchanged to make it fit in a pointer size. This one is
2753 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2754
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2756 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2757 are the same as those for the <a href="#i_bitcast">bitcast
2758 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2759
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2761 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2763 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2764 instruction, the index list may have zero or more indexes, which are
2765 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2766
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2767 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2768 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2769
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2771 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2772
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2773 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2774 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2775
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2776 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2777 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2778 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2779
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2780 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2781 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2782 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2783
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2784 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2785 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2786 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2787
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2788 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2789 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2790 constants. The index list is interpreted in a similar manner as indices in
2791 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2792 index value must be specified.</dd>
2793
2794 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2795 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2796 constants. The index list is interpreted in a similar manner as indices in
2797 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2798 index value must be specified.</dd>
2799
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2800 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2801 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2802 be any of the <a href="#binaryops">binary</a>
2803 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2804 on operands are the same as those for the corresponding instruction
2805 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2806</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2807
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2808</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2809
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2810</div>
2811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2812<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2813<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2814<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2815<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2816<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2817<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2818<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2819</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2820
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2821<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2823<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2824 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2825 a special value. This value represents the inline assembler as a string
2826 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2827 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2828 expression has side effects, and a flag indicating whether the function
2829 containing the asm needs to align its stack conservatively. An example
2830 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2831
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2832<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2833i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2834</pre>
2835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2836<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2837 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2838 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2839
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2840<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2841%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]2842</pre>
2843
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2844<p>Inline asms with side effects not visible in the constraint list must be
2845 marked as having side effects. This is done through the use of the
2846 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2847
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2848<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2849call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2850</pre>
2851
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2852<p>In some cases inline asms will contain code that will not work unless the
2853 stack is aligned in some way, such as calls or SSE instructions on x86,
2854 yet will not contain code that does that alignment within the asm.
2855 The compiler should make conservative assumptions about what the asm might
2856 contain and should generate its usual stack alignment code in the prologue
2857 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2858
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2859<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2860call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2861</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2862
2863<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2864 first.</p>
2865
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2866<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2867<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868 documented here. Constraints on what can be done (e.g. duplication, moving,
2869 etc need to be documented). This is probably best done by reference to
2870 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2871 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2872
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2873<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2874<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2875 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2876</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2878<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2879
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2880<p>The call instructions that wrap inline asm nodes may have a
2881 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2882 integers. If present, the code generator will use the integer as the
2883 location cookie value when report errors through the <tt>LLVMContext</tt>
2884 error reporting mechanisms. This allows a front-end to correlate backend
2885 errors that occur with inline asm back to the source code that produced it.
2886 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2887
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2888<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2889call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2890...
2891!42 = !{ i32 1234567 }
2892</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2893
2894<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]2895 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2896 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]2897
2898</div>
2899
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2900</div>
2901
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2902<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2903<h3>
2904 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2905</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2906
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2907<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2908
2909<p>LLVM IR allows metadata to be attached to instructions in the program that
2910 can convey extra information about the code to the optimizers and code
2911 generator. One example application of metadata is source-level debug
2912 information. There are two metadata primitives: strings and nodes. All
2913 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2914 preceding exclamation point ('<tt>!</tt>').</p>
2915
2916<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2917 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2918 "<tt>xx</tt>" is the two digit hex code. For example:
2919 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2920
2921<p>Metadata nodes are represented with notation similar to structure constants
2922 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2923 exclamation point). Metadata nodes can have any values as their operand. For
2924 example:</p>
2925
2926<div class="doc_code">
2927<pre>
2928!{ metadata !"test\00", i32 10}
2929</pre>
2930</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2931
2932<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2933 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2934 example:</p>
2935
2936<div class="doc_code">
2937<pre>
2938!foo = metadata !{!4, !3}
2939</pre>
2940</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2941
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2942<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2943 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2944
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2945<div class="doc_code">
2946<pre>
2947call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2948</pre>
2949</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2950
2951<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2952 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2953 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2954
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2955<div class="doc_code">
2956<pre>
2957%indvar.next = add i64 %indvar, 1, !dbg !21
2958</pre>
2959</div>
2960
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2961<p>More information about specific metadata nodes recognized by the optimizers
2962 and code generator is found below.</p>
2963
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2964<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2965<h4>
2966 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2967</h4>
2968
2969<div>
2970
2971<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2972 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2973 a type system of a higher level language. This can be used to implement
2974 typical C/C++ TBAA, but it can also be used to implement custom alias
2975 analysis behavior for other languages.</p>
2976
2977<p>The current metadata format is very simple. TBAA metadata nodes have up to
2978 three fields, e.g.:</p>
2979
2980<div class="doc_code">
2981<pre>
2982!0 = metadata !{ metadata !"an example type tree" }
2983!1 = metadata !{ metadata !"int", metadata !0 }
2984!2 = metadata !{ metadata !"float", metadata !0 }
2985!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2986</pre>
2987</div>
2988
2989<p>The first field is an identity field. It can be any value, usually
2990 a metadata string, which uniquely identifies the type. The most important
2991 name in the tree is the name of the root node. Two trees with
2992 different root node names are entirely disjoint, even if they
2993 have leaves with common names.</p>
2994
2995<p>The second field identifies the type's parent node in the tree, or
2996 is null or omitted for a root node. A type is considered to alias
2997 all of its descendants and all of its ancestors in the tree. Also,
2998 a type is considered to alias all types in other trees, so that
2999 bitcode produced from multiple front-ends is handled conservatively.</p>
3000
3001<p>If the third field is present, it's an integer which if equal to 1
3002 indicates that the type is "constant" (meaning
3003 <tt>pointsToConstantMemory</tt> should return true; see
3004 <a href="AliasAnalysis.html#OtherItfs">other useful
3005 <tt>AliasAnalysis</tt> methods</a>).</p>
3006
3007</div>
3008
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]3009<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3010<h4>
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3011 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3012</h4>
3013
3014<div>
3015
Duncan Sands34bd91a2012-04-14 12:36:06 +0000[diff] [blame]3016<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3017 type. It can be used to express the maximum acceptable error in the result of
3018 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3019 more efficient but less accurate method of computing it. ULP is defined as
3020 follows:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3021
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]3022<blockquote>
3023
3024<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3025 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3026 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3027 distance between the two non-equal finite floating-point numbers nearest
3028 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3029
3030</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3031
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3032<p>The metadata node shall consist of a single positive floating point number
Duncan Sands9af62982012-04-16 19:39:33 +0000[diff] [blame]3033 representing the maximum relative error, for example:</p>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3034
3035<div class="doc_code">
3036<pre>
Duncan Sands05f4df82012-04-16 16:28:59 +0000[diff] [blame]3037!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3038</pre>
3039</div>
3040
NAKAMURA Takumic9d9b922012-03-27 11:25:16 +0000[diff] [blame]3041</div>
3042
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3043<!-- _______________________________________________________________________ -->
3044<h4>
3045 <a name="range">'<tt>range</tt>' Metadata</a>
3046</h4>
3047
3048<div>
3049<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3050 expresses the possible ranges the loaded value is in. The ranges are
3051 represented with a flattened list of integers. The loaded value is known to
3052 be in the union of the ranges defined by each consecutive pair. Each pair
3053 has the following properties:</p>
3054<ul>
3055 <li>The type must match the type loaded by the instruction.</li>
3056 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3057 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3058 <li>The range is allowed to wrap.</li>
3059 <li>The range should not represent the full or empty set. That is,
3060 <tt>a!=b</tt>. </li>
3061</ul>
Rafael Espindolae3c5f3e2012-05-31 16:04:26 +0000[diff] [blame]3062<p> In addition, the pairs must be in signed order of the lower bound and
3063 they must be non-contiguous.</p>
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3064
3065<p>Examples:</p>
3066<div class="doc_code">
3067<pre>
3068 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3069 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3070 %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]3071 %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]3072...
3073!0 = metadata !{ i8 0, i8 2 }
3074!1 = metadata !{ i8 255, i8 2 }
3075!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindola97d77872012-05-31 13:45:46 +0000[diff] [blame]3076!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindolaef9f5502012-03-24 00:14:51 +0000[diff] [blame]3077</pre>
3078</div>
3079</div>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3080</div>
3081
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3082</div>
3083
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3084<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3085<h2>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3086 <a name="module_flags">Module Flags Metadata</a>
3087</h2>
3088<!-- *********************************************************************** -->
3089
3090<div>
3091
3092<p>Information about the module as a whole is difficult to convey to LLVM's
3093 subsystems. The LLVM IR isn't sufficient to transmit this
3094 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3095 facilitate this. These flags are in the form of key / value pairs &mdash;
3096 much like a dictionary &mdash; making it easy for any subsystem who cares
3097 about a flag to look it up.</p>
3098
3099<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3100 triplets. Each triplet has the following form:</p>
3101
3102<ul>
3103 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3104 when two (or more) modules are merged together, and it encounters two (or
3105 more) metadata with the same ID. The supported behaviors are described
3106 below.</li>
3107
3108 <li>The second element is a metadata string that is a unique ID for the
3109 metadata. How each ID is interpreted is documented below.</li>
3110
3111 <li>The third element is the value of the flag.</li>
3112</ul>
3113
3114<p>When two (or more) modules are merged together, the resulting
3115 <tt>llvm.module.flags</tt> metadata is the union of the
3116 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3117 with the <i>Override</i> behavior, which may override another flag's value
3118 (see below).</p>
3119
3120<p>The following behaviors are supported:</p>
3121
3122<table border="1" cellspacing="0" cellpadding="4">
3123 <tbody>
3124 <tr>
3125 <th>Value</th>
3126 <th>Behavior</th>
3127 </tr>
3128 <tr>
3129 <td>1</td>
3130 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3131 <dl>
3132 <dt><b>Error</b></dt>
3133 <dd>Emits an error if two values disagree. It is an error to have an ID
3134 with both an Error and a Warning behavior.</dd>
3135 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3136 </td>
3137 </tr>
3138 <tr>
3139 <td>2</td>
3140 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3141 <dl>
3142 <dt><b>Warning</b></dt>
3143 <dd>Emits a warning if two values disagree.</dd>
3144 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3145 </td>
3146 </tr>
3147 <tr>
3148 <td>3</td>
3149 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3150 <dl>
3151 <dt><b>Require</b></dt>
3152 <dd>Emits an error when the specified value is not present or doesn't
3153 have the specified value. It is an error for two (or more)
3154 <tt>llvm.module.flags</tt> with the same ID to have the Require
3155 behavior but different values. There may be multiple Require flags
3156 per ID.</dd>
3157 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3158 </td>
3159 </tr>
3160 <tr>
3161 <td>4</td>
3162 <td align="left">
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3163 <dl>
3164 <dt><b>Override</b></dt>
3165 <dd>Uses the specified value if the two values disagree. It is an
3166 error for two (or more) <tt>llvm.module.flags</tt> with the same
3167 ID to have the Override behavior but different values.</dd>
3168 </dl>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3169 </td>
3170 </tr>
3171 </tbody>
3172</table>
3173
3174<p>An example of module flags:</p>
3175
3176<pre class="doc_code">
3177!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3178!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3179!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3180!3 = metadata !{ i32 3, metadata !"qux",
3181 metadata !{
3182 metadata !"foo", i32 1
3183 }
3184}
3185!llvm.module.flags = !{ !0, !1, !2, !3 }
3186</pre>
3187
3188<ul>
3189 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3190 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3191 error if their values are not equal.</p></li>
3192
3193 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3194 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3195 value '37' if their values are not equal.</p></li>
3196
3197 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3198 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3199 warning if their values are not equal.</p></li>
3200
3201 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3202
3203<pre class="doc_code">
3204metadata !{ metadata !"foo", i32 1 }
3205</pre>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3206
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3207 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3208 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3209 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3210 the same value or an error will be issued.</p></li>
3211</ul>
3212
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3213
3214<!-- ======================================================================= -->
3215<h3>
3216<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3217</h3>
3218
3219<div>
3220
3221<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3222 in a special section called "image info". The metadata consists of a version
3223 number and a bitmask specifying what types of garbage collection are
3224 supported (if any) by the file. If two or more modules are linked together
3225 their garbage collection metadata needs to be merged rather than appended
3226 together.</p>
3227
3228<p>The Objective-C garbage collection module flags metadata consists of the
3229 following key-value pairs:</p>
3230
3231<table border="1" cellspacing="0" cellpadding="4">
Bill Wendling4fa13cc2012-03-06 09:23:25 +0000[diff] [blame]3232 <col width="30%">
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3233 <tbody>
3234 <tr>
Bill Wendlingd672d9c2012-03-06 09:17:04 +0000[diff] [blame]3235 <th>Key</th>
Bill Wendling73462772012-02-16 01:10:50 +0000[diff] [blame]3236 <th>Value</th>
3237 </tr>
3238 <tr>
3239 <td><tt>Objective-C&nbsp;Version</tt></td>
3240 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3241 version. Valid values are 1 and 2.</td>
3242 </tr>
3243 <tr>
3244 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3245 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3246 section. Currently always 0.</td>
3247 </tr>
3248 <tr>
3249 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3250 <td align="left"><b>[Required]</b> &mdash; The section to place the
3251 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3252 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3253 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3254 </tr>
3255 <tr>
3256 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3257 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3258 collection is supported or not. Valid values are 0, for no garbage
3259 collection, and 2, for garbage collection supported.</td>
3260 </tr>
3261 <tr>
3262 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3263 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3264 collection is supported. If present, its value must be 6. This flag
3265 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3266 value 2.</td>
3267 </tr>
3268 </tbody>
3269</table>
3270
3271<p>Some important flag interactions:</p>
3272
3273<ul>
3274 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3275 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3276 2, then the resulting module has the <tt>Objective-C Garbage
3277 Collection</tt> flag set to 0.</li>
3278
3279 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3280 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3281</ul>
3282
3283</div>
3284
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame]3285</div>
3286
3287<!-- *********************************************************************** -->
3288<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3289 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3290</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3291<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3292<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3293<p>LLVM has a number of "magic" global variables that contain data that affect
3294code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3295of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3296section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3297by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3298
3299<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3300<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3301<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3302</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3303
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3304<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3305
3306<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3307href="#linkage_appending">appending linkage</a>. This array contains a list of
3308pointers to global variables and functions which may optionally have a pointer
3309cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3310
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3311<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3312<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3313@X = global i8 4
3314@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3315
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3316@llvm.used = appending global [2 x i8*] [
3317 i8* @X,
3318 i8* bitcast (i32* @Y to i8*)
3319], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3320</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3321</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3322
3323<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]3324 compiler, assembler, and linker are required to treat the symbol as if there
3325 is a reference to the global that it cannot see. For example, if a variable
3326 has internal linkage and no references other than that from
3327 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3328 represent references from inline asms and other things the compiler cannot
3329 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3330
3331<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]3332 object file to prevent the assembler and linker from molesting the
3333 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3334
3335</div>
3336
3337<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3338<h3>
3339 <a name="intg_compiler_used">
3340 The '<tt>llvm.compiler.used</tt>' Global Variable
3341 </a>
3342</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3343
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3344<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3345
3346<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3347 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3348 touching the symbol. On targets that support it, this allows an intelligent
3349 linker to optimize references to the symbol without being impeded as it would
3350 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3351
3352<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]3353 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3354
3355</div>
3356
3357<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3358<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3359<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3360</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3361
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3362<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3363
3364<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3365<pre>
3366%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3367@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3368</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3369</div>
3370
3371<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3372 functions and associated priorities. The functions referenced by this array
3373 will be called in ascending order of priority (i.e. lowest first) when the
3374 module is loaded. The order of functions with the same priority is not
3375 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3376
3377</div>
3378
3379<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3380<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3381<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3382</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3383
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3384<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3385
3386<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3387<pre>
3388%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3389@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3390</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3391</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3392
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3393<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3394 and associated priorities. The functions referenced by this array will be
3395 called in descending order of priority (i.e. highest first) when the module
3396 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3397
3398</div>
3399
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3400</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3401
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3402<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3403<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3404<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3405
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3406<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3407
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3408<p>The LLVM instruction set consists of several different classifications of
3409 instructions: <a href="#terminators">terminator
3410 instructions</a>, <a href="#binaryops">binary instructions</a>,
3411 <a href="#bitwiseops">bitwise binary instructions</a>,
3412 <a href="#memoryops">memory instructions</a>, and
3413 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3414
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3415<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3416<h3>
3417 <a name="terminators">Terminator Instructions</a>
3418</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3419
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3420<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3421
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3423 in a program ends with a "Terminator" instruction, which indicates which
3424 block should be executed after the current block is finished. These
3425 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3426 control flow, not values (the one exception being the
3427 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3428
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3429<p>The terminator instructions are:
3430 '<a href="#i_ret"><tt>ret</tt></a>',
3431 '<a href="#i_br"><tt>br</tt></a>',
3432 '<a href="#i_switch"><tt>switch</tt></a>',
3433 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3434 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3435 '<a href="#i_resume"><tt>resume</tt></a>', and
3436 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3437
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3438<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3439<h4>
3440 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3441</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3443<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3445<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3446<pre>
3447 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]3448 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3449</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3450
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3451<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3453 a value) from a function back to the caller.</p>
3454
3455<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3456 value and then causes control flow, and one that just causes control flow to
3457 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3458
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3459<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3460<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3461 return value. The type of the return value must be a
3462 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3463
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3465 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3466 value or a return value with a type that does not match its type, or if it
3467 has a void return type and contains a '<tt>ret</tt>' instruction with a
3468 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3469
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3471<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3472 the calling function's context. If the caller is a
3473 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3474 instruction after the call. If the caller was an
3475 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3476 the beginning of the "normal" destination block. If the instruction returns
3477 a value, that value shall set the call or invoke instruction's return
3478 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3479
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3480<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3481<pre>
3482 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3483 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3484 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]3485</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3486
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3487</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3488<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3489<h4>
3490 <a name="i_br">'<tt>br</tt>' Instruction</a>
3491</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3492
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3493<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3494
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3495<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3496<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3497 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3498 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3499</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3500
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3502<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3503 different basic block in the current function. There are two forms of this
3504 instruction, corresponding to a conditional branch and an unconditional
3505 branch.</p>
3506
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3509 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3510 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3511 target.</p>
3512
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3513<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3514<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3516 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3517 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3518
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3519<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3520<pre>
3521Test:
3522 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3523 br i1 %cond, label %IfEqual, label %IfUnequal
3524IfEqual:
3525 <a href="#i_ret">ret</a> i32 1
3526IfUnequal:
3527 <a href="#i_ret">ret</a> i32 0
3528</pre>
3529
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3530</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3532<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3533<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3534 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3535</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3536
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3537<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3538
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3540<pre>
3541 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3542</pre>
3543
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3544<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3545<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]3546 several different places. It is a generalization of the '<tt>br</tt>'
3547 instruction, allowing a branch to occur to one of many possible
3548 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3551<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3553 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3554 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3555
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3556<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3557<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3558 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3559 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3560 transferred to the corresponding destination; otherwise, control flow is
3561 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3562
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3563<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3564<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3565 <tt>switch</tt> instruction, this instruction may be code generated in
3566 different ways. For example, it could be generated as a series of chained
3567 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3568
3569<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3570<pre>
3571 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3572 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3573 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3574
3575 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3576 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3577
3578 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3579 switch i32 %val, label %otherwise [ i32 0, label %onzero
3580 i32 1, label %onone
3581 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3582</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3584</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3585
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3586
3587<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3588<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3589 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3590</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3591
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3592<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3593
3594<h5>Syntax:</h5>
3595<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3596 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]3597</pre>
3598
3599<h5>Overview:</h5>
3600
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3601<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3602 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3603 "<tt>address</tt>". Address must be derived from a <a
3604 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3605
3606<h5>Arguments:</h5>
3607
3608<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3609 rest of the arguments indicate the full set of possible destinations that the
3610 address may point to. Blocks are allowed to occur multiple times in the
3611 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3612
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3613<p>This destination list is required so that dataflow analysis has an accurate
3614 understanding of the CFG.</p>
3615
3616<h5>Semantics:</h5>
3617
3618<p>Control transfers to the block specified in the address argument. All
3619 possible destination blocks must be listed in the label list, otherwise this
3620 instruction has undefined behavior. This implies that jumps to labels
3621 defined in other functions have undefined behavior as well.</p>
3622
3623<h5>Implementation:</h5>
3624
3625<p>This is typically implemented with a jump through a register.</p>
3626
3627<h5>Example:</h5>
3628<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3629 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3630</pre>
3631
3632</div>
3633
3634
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3635<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3636<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3637 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3638</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3639
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3640<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3641
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3642<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3643<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3644 &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]3645 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3646</pre>
3647
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3648<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3649<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3650 function, with the possibility of control flow transfer to either the
3651 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3652 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3653 control flow will return to the "normal" label. If the callee (or any
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3654 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3655 instruction or other exception handling mechanism, control is interrupted and
3656 continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3657
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3658<p>The '<tt>exception</tt>' label is a
3659 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3660 exception. As such, '<tt>exception</tt>' label is required to have the
3661 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosierc28f3e92011-12-09 02:00:44 +0000[diff] [blame]3662 the information about the behavior of the program after unwinding
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3663 happens, as its first non-PHI instruction. The restrictions on the
3664 "<tt>landingpad</tt>" instruction's tightly couples it to the
3665 "<tt>invoke</tt>" instruction, so that the important information contained
3666 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3667 code motion.</p>
3668
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3669<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3670<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3671
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3672<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3673 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3674 convention</a> the call should use. If none is specified, the call
3675 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3676
3677 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3679 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3680
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3681 <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]3682 function value being invoked. In most cases, this is a direct function
3683 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3684 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3685
3686 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3687 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3688
3689 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3690 signature argument types and parameter attributes. All arguments must be
3691 of <a href="#t_firstclass">first class</a> type. If the function
3692 signature indicates the function accepts a variable number of arguments,
3693 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3694
3695 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3696 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3697
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3698 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3699 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3700 handling mechanism.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3701
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3702 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3703 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3704 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3705</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3706
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3707<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3708<p>This instruction is designed to operate as a standard
3709 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3710 primary difference is that it establishes an association with a label, which
3711 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3712
3713<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3715 exception. Additionally, this is important for implementation of
3716 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3717
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718<p>For the purposes of the SSA form, the definition of the value returned by the
3719 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3720 block to the "normal" label. If the callee unwinds then no return value is
3721 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3722
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3723<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3724<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3725 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3726 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3727 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3728 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3729</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3730
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3732
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3733 <!-- _______________________________________________________________________ -->
3734
3735<h4>
3736 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3737</h4>
3738
3739<div>
3740
3741<h5>Syntax:</h5>
3742<pre>
3743 resume &lt;type&gt; &lt;value&gt;
3744</pre>
3745
3746<h5>Overview:</h5>
3747<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3748 successors.</p>
3749
3750<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3751<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3752 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3753 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3754
3755<h5>Semantics:</h5>
3756<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3757 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3758 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3759
3760<h5>Example:</h5>
3761<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3762 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3763</pre>
3764
3765</div>
3766
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3767<!-- _______________________________________________________________________ -->
3768
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3769<h4>
3770 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3771</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3772
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3773<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3774
3775<h5>Syntax:</h5>
3776<pre>
3777 unreachable
3778</pre>
3779
3780<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3781<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3782 instruction is used to inform the optimizer that a particular portion of the
3783 code is not reachable. This can be used to indicate that the code after a
3784 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3787<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3788
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3789</div>
3790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3791</div>
3792
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3793<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3794<h3>
3795 <a name="binaryops">Binary Operations</a>
3796</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3798<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3799
3800<p>Binary operators are used to do most of the computation in a program. They
3801 require two operands of the same type, execute an operation on them, and
3802 produce a single value. The operands might represent multiple data, as is
3803 the case with the <a href="#t_vector">vector</a> data type. The result value
3804 has the same type as its operands.</p>
3805
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3806<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3808<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3809<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3810 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3811</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3812
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3813<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3814
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3815<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3816<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3817 &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]3818 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3819 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3820 &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]3821</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3822
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3823<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3824<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3825
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3826<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3827<p>The two arguments to the '<tt>add</tt>' instruction must
3828 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3829 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3831<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3832<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3833
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834<p>If the sum has unsigned overflow, the result returned is the mathematical
3835 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]3836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3837<p>Because LLVM integers use a two's complement representation, this instruction
3838 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3839
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3840<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3841 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3842 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3843 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3844 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3847<pre>
3848 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3849</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3851</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3852
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3853<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3854<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3855 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3856</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3857
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3858<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3859
3860<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3861<pre>
3862 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3863</pre>
3864
3865<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3866<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3867
3868<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3869<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3870 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3871 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3872
3873<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3874<p>The value produced is the floating point sum of the two operands.</p>
3875
3876<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3877<pre>
3878 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3879</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3880
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3881</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3882
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3883<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3884<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3885 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3886</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3887
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3888<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3890<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3891<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3892 &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]3893 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3894 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3895 &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]3896</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3897
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3899<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3900 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3901
3902<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903 '<tt>neg</tt>' instruction present in most other intermediate
3904 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3905
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907<p>The two arguments to the '<tt>sub</tt>' instruction must
3908 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3909 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3910
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3912<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3913
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3914<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3915 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3916 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3917
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3918<p>Because LLVM integers use a two's complement representation, this instruction
3919 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3920
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3921<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3922 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3923 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3924 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3925 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3927<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3928<pre>
3929 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3930 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3931</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3932
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3933</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3936<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3937 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3938</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3939
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3940<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3941
3942<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3943<pre>
3944 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3945</pre>
3946
3947<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3948<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3950
3951<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3952 '<tt>fneg</tt>' instruction present in most other intermediate
3953 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3954
3955<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3956<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3958 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3959
3960<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3961<p>The value produced is the floating point difference of the two operands.</p>
3962
3963<h5>Example:</h5>
3964<pre>
3965 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3966 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3967</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3968
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3969</div>
3970
3971<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3972<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3973 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3974</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3975
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3976<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3978<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3979<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3980 &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]3981 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3982 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3983 &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]3984</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3985
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3986<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3987<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3989<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3990<p>The two arguments to the '<tt>mul</tt>' instruction must
3991 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3992 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3993
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3994<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3995<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3996
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3997<p>If the result of the multiplication has unsigned overflow, the result
3998 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3999 width of the result.</p>
4000
4001<p>Because LLVM integers use a two's complement representation, and the result
4002 is the same width as the operands, this instruction returns the correct
4003 result for both signed and unsigned integers. If a full product
4004 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4005 be sign-extended or zero-extended as appropriate to the width of the full
4006 product.</p>
4007
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]4008<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4009 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4010 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4011 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]4012 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4013
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4014<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4015<pre>
4016 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4017</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4018
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4019</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4020
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4021<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4022<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4023 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4024</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4025
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4026<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4027
4028<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4029<pre>
4030 &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]4031</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4032
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4033<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4034<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4035
4036<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4037<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4038 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4039 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4040
4041<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4042<p>The value produced is the floating point product of the two operands.</p>
4043
4044<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045<pre>
4046 &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]4047</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4048
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]4049</div>
4050
4051<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4052<h4>
4053 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4054</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4055
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4056<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4057
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4058<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4060 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4061 &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]4062</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4064<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4066
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4067<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4068<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4070 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4071
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4072<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4073<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4074
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4075<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4076 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4077
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4078<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4079
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]4080<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4081 <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]4082 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4083
4084
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4085<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4086<pre>
4087 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4088</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4089
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4090</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4092<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4093<h4>
4094 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4095</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4097<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4098
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4099<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4100<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4101 &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]4102 &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]4103</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4104
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4105<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4106<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4107
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4108<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4109<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4110 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4111 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4112
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4113<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114<p>The value produced is the signed integer quotient of the two operands rounded
4115 towards zero.</p>
4116
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4117<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4118 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4119
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4120<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4121 undefined behavior; this is a rare case, but can occur, for example, by doing
4122 a 32-bit division of -2147483648 by -1.</p>
4123
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]4124<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4125 <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]4126 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]4127
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4128<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129<pre>
4130 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4131</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4132
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4133</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4134
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4135<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4136<h4>
4137 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4138</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4139
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4140<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4141
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4142<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4143<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4144 &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]4145</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4146
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4147<h5>Overview:</h5>
4148<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4149
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4150<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4151<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4152 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4153 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4154
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4155<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4156<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4157
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4158<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4159<pre>
4160 &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]4161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4163</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4164
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4165<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4166<h4>
4167 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4168</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4169
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4170<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4172<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4173<pre>
4174 &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]4175</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4176
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4177<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4178<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4179 division of its two arguments.</p>
4180
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4181<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4182<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4183 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4184 values. Both arguments must have identical types.</p>
4185
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4186<h5>Semantics:</h5>
4187<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188 This instruction always performs an unsigned division to get the
4189 remainder.</p>
4190
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4191<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4192 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4193
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4194<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4195
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4196<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4197<pre>
4198 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4199</pre>
4200
4201</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4202
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4203<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4204<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4205 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4206</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4207
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4208<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4209
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4210<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4211<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4212 &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]4213</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4214
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4215<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4216<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4217 division of its two operands. This instruction can also take
4218 <a href="#t_vector">vector</a> versions of the values in which case the
4219 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]4220
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4221<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4222<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4223 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4224 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4225
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4226<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4227<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4228 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4229 <i>modulo</i> operator (where the result is either zero or has the same sign
4230 as the divisor, <tt>op2</tt>) of a value.
4231 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4233 Math Forum</a>. For a table of how this is implemented in various languages,
4234 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4235 Wikipedia: modulo operation</a>.</p>
4236
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4237<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4238 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4239
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4240<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4241 Overflow also leads to undefined behavior; this is a rare case, but can
4242 occur, for example, by taking the remainder of a 32-bit division of
4243 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4244 lets srem be implemented using instructions that return both the result of
4245 the division and the remainder.)</p>
4246
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4247<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4248<pre>
4249 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4250</pre>
4251
4252</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4253
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4254<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4255<h4>
4256 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4257</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4258
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4259<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4260
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4261<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4262<pre>
4263 &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]4264</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4265
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4266<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4268 its two operands.</p>
4269
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4270<h5>Arguments:</h5>
4271<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4272 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4273 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4274
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4275<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4276<p>This instruction returns the <i>remainder</i> of a division. The remainder
4277 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4278
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4279<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4280<pre>
4281 &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]4282</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4283
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4284</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4285
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4286</div>
4287
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4288<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4289<h3>
4290 <a name="bitwiseops">Bitwise Binary Operations</a>
4291</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4292
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4293<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294
4295<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4296 program. They are generally very efficient instructions and can commonly be
4297 strength reduced from other instructions. They require two operands of the
4298 same type, execute an operation on them, and produce a single value. The
4299 resulting value is the same type as its operands.</p>
4300
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4301<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4302<h4>
4303 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4304</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4306<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4308<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4310 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4311 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4312 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4313 &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]4314</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4315
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4316<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4317<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4318 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4319
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4320<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4321<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4322 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4323 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4324
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4325<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4326<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4327 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4328 is (statically or dynamically) negative or equal to or larger than the number
4329 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4330 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4331 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4332
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4333<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4334 <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]4335 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4336 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4337 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4338 they would if the shift were expressed as a mul instruction with the same
4339 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4340
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341<h5>Example:</h5>
4342<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4343 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4344 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4345 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4346 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4347 &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]4348</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4350</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4352<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4353<h4>
4354 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4355</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4356
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4357<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4359<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4361 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4362 &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]4363</pre>
4364
4365<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4366<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4367 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4368
4369<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4370<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4371 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4372 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4373
4374<h5>Semantics:</h5>
4375<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4376 significant bits of the result will be filled with zero bits after the shift.
4377 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4378 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4379 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4380 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4381
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4382<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4383 <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]4384 shifted out are non-zero.</p>
4385
4386
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4387<h5>Example:</h5>
4388<pre>
4389 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4390 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4391 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4392 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4393 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4394 &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]4395</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4396
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4397</div>
4398
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4399<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4400<h4>
4401 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4402</h4>
4403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4404<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4405
4406<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4407<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4408 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4409 &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]4410</pre>
4411
4412<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4413<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4414 operand shifted to the right a specified number of bits with sign
4415 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4416
4417<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4418<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4419 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4420 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4421
4422<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4423<p>This instruction always performs an arithmetic shift right operation, The
4424 most significant bits of the result will be filled with the sign bit
4425 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4426 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4427 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4428 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4429
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4430<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4431 <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]4432 shifted out are non-zero.</p>
4433
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4434<h5>Example:</h5>
4435<pre>
4436 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4437 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4438 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4439 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4440 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4441 &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]4442</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4443
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4444</div>
4445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4446<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4447<h4>
4448 <a name="i_and">'<tt>and</tt>' Instruction</a>
4449</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4450
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4451<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4452
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4453<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4454<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4455 &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]4456</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4457
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4458<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4459<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4460 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4461
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4462<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4463<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4464 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4465 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4466
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4467<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4468<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4470<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4471 <tbody>
4472 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4473 <th>In0</th>
4474 <th>In1</th>
4475 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4476 </tr>
4477 <tr>
4478 <td>0</td>
4479 <td>0</td>
4480 <td>0</td>
4481 </tr>
4482 <tr>
4483 <td>0</td>
4484 <td>1</td>
4485 <td>0</td>
4486 </tr>
4487 <tr>
4488 <td>1</td>
4489 <td>0</td>
4490 <td>0</td>
4491 </tr>
4492 <tr>
4493 <td>1</td>
4494 <td>1</td>
4495 <td>1</td>
4496 </tr>
4497 </tbody>
4498</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4499
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4500<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4501<pre>
4502 &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]4503 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4504 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4505</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4506</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4507<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4508<h4>
4509 <a name="i_or">'<tt>or</tt>' Instruction</a>
4510</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4511
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4512<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4513
4514<h5>Syntax:</h5>
4515<pre>
4516 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4517</pre>
4518
4519<h5>Overview:</h5>
4520<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4521 two operands.</p>
4522
4523<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4524<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4525 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4526 values. Both arguments must have identical types.</p>
4527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4528<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4529<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4530
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4531<table border="1" cellspacing="0" cellpadding="4">
4532 <tbody>
4533 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4534 <th>In0</th>
4535 <th>In1</th>
4536 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4537 </tr>
4538 <tr>
4539 <td>0</td>
4540 <td>0</td>
4541 <td>0</td>
4542 </tr>
4543 <tr>
4544 <td>0</td>
4545 <td>1</td>
4546 <td>1</td>
4547 </tr>
4548 <tr>
4549 <td>1</td>
4550 <td>0</td>
4551 <td>1</td>
4552 </tr>
4553 <tr>
4554 <td>1</td>
4555 <td>1</td>
4556 <td>1</td>
4557 </tr>
4558 </tbody>
4559</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4560
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4561<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562<pre>
4563 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4564 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4565 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4566</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4567
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4568</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4569
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4570<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4571<h4>
4572 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4573</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4575<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4576
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4577<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4578<pre>
4579 &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]4580</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4581
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4582<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4583<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4584 its two operands. The <tt>xor</tt> is used to implement the "one's
4585 complement" operation, which is the "~" operator in C.</p>
4586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4587<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4588<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4589 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4590 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4592<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4593<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4595<table border="1" cellspacing="0" cellpadding="4">
4596 <tbody>
4597 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4598 <th>In0</th>
4599 <th>In1</th>
4600 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4601 </tr>
4602 <tr>
4603 <td>0</td>
4604 <td>0</td>
4605 <td>0</td>
4606 </tr>
4607 <tr>
4608 <td>0</td>
4609 <td>1</td>
4610 <td>1</td>
4611 </tr>
4612 <tr>
4613 <td>1</td>
4614 <td>0</td>
4615 <td>1</td>
4616 </tr>
4617 <tr>
4618 <td>1</td>
4619 <td>1</td>
4620 <td>0</td>
4621 </tr>
4622 </tbody>
4623</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4624
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4625<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4626<pre>
4627 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4628 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4629 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4630 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4631</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4632
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4633</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4634
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4635</div>
4636
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4637<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4638<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4639 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4640</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4641
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4642<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4643
4644<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4645 target-independent manner. These instructions cover the element-access and
4646 vector-specific operations needed to process vectors effectively. While LLVM
4647 does directly support these vector operations, many sophisticated algorithms
4648 will want to use target-specific intrinsics to take full advantage of a
4649 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4650
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4651<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4652<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4653 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4654</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4655
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4656<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4657
4658<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4659<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4660 &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]4661</pre>
4662
4663<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4665 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4666
4667
4668<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4670 of <a href="#t_vector">vector</a> type. The second operand is an index
4671 indicating the position from which to extract the element. The index may be
4672 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4673
4674<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4675<p>The result is a scalar of the same type as the element type of
4676 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4677 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4678 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4679
4680<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4681<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4682 &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]4683</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4684
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4686
4687<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4688<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4689 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4690</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4691
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4692<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4693
4694<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4695<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4696 &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]4697</pre>
4698
4699<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4701 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4702
4703<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4705 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4706 whose type must equal the element type of the first operand. The third
4707 operand is an index indicating the position at which to insert the value.
4708 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4709
4710<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4712 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4713 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4714 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4715
4716<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4717<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4718 &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]4719</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4720
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4721</div>
4722
4723<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4724<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4725 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4726</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4727
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4728<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4729
4730<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4731<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4732 &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]4733</pre>
4734
4735<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4736<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4737 from two input vectors, returning a vector with the same element type as the
4738 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4739
4740<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsbe3d3a62012-06-14 14:58:28 +0000[diff] [blame^]4742 with the same type. The third argument is a shuffle mask whose
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4743 element type is always 'i32'. The result of the instruction is a vector
4744 whose length is the same as the shuffle mask and whose element type is the
4745 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4746
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4747<p>The shuffle mask operand is required to be a constant vector with either
4748 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4749
4750<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4751<p>The elements of the two input vectors are numbered from left to right across
4752 both of the vectors. The shuffle mask operand specifies, for each element of
4753 the result vector, which element of the two input vectors the result element
4754 gets. The element selector may be undef (meaning "don't care") and the
4755 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4756
4757<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4758<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4759 &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]4760 &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]4761 &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]4762 &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]4763 &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]4764 &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]4765 &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]4766 &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]4767</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4768
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4770
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4771</div>
4772
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4773<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4774<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4775 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4776</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4777
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4778<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4779
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4780<p>LLVM supports several instructions for working with
4781 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4782
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4783<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4784<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4785 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4786</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4787
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4788<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4789
4790<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4791<pre>
4792 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4793</pre>
4794
4795<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4796<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4797 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4798
4799<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4801 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4802 <a href="#t_array">array</a> type. The operands are constant indices to
4803 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4804 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4805 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4806 <ul>
4807 <li>Since the value being indexed is not a pointer, the first index is
4808 omitted and assumed to be zero.</li>
4809 <li>At least one index must be specified.</li>
4810 <li>Not only struct indices but also array indices must be in
4811 bounds.</li>
4812 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4813
4814<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4815<p>The result is the value at the position in the aggregate specified by the
4816 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4817
4818<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4819<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4820 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4821</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4823</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4824
4825<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4826<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4827 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4828</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4829
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4830<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4831
4832<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4833<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4834 &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]4835</pre>
4836
4837<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4838<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4839 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4840
4841<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4842<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4843 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4844 <a href="#t_array">array</a> type. The second operand is a first-class
4845 value to insert. The following operands are constant indices indicating
4846 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]4847 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4848 value to insert must have the same type as the value identified by the
4849 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4850
4851<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4852<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4853 that of <tt>val</tt> except that the value at the position specified by the
4854 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4855
4856<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4857<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4858 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4859 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4860 %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]4861</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4863</div>
4864
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4865</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4866
4867<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4868<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4869 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4870</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4871
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4872<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4874<p>A key design point of an SSA-based representation is how it represents
4875 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4876 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4877 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4878
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4879<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4880<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4881 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4882</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4883
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4884<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4885
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4886<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4887<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4888 &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]4889</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4890
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4891<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4892<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4893 currently executing function, to be automatically released when this function
4894 returns to its caller. The object is always allocated in the generic address
4895 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4896
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4897<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4898<p>The '<tt>alloca</tt>' instruction
4899 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4900 runtime stack, returning a pointer of the appropriate type to the program.
4901 If "NumElements" is specified, it is the number of elements allocated,
4902 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4903 specified, the value result of the allocation is guaranteed to be aligned to
4904 at least that boundary. If not specified, or if zero, the target can choose
4905 to align the allocation on any convenient boundary compatible with the
4906 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4907
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4908<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4910<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4911<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4912 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4913 memory is automatically released when the function returns. The
4914 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4915 variables that must have an address available. When the function returns
4916 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]4917 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]4918 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4919 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewyckyf70a2bd2012-03-18 09:35:50 +0000[diff] [blame]4920 not specified.</p>
Nick Lewyckyefe5e2e2012-02-29 08:26:44 +0000[diff] [blame]4921
4922<p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4923
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4924<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4925<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4926 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4927 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4928 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4929 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4930</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4931
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4932</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4933
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4934<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4935<h4>
4936 <a name="i_load">'<tt>load</tt>' Instruction</a>
4937</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4938
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4939<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4941<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4942<pre>
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]4943 &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]4944 &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]4945 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4946</pre>
4947
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4948<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4949<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4950
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4951<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4953 from which to load. The pointer must point to
4954 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4955 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4956 number or order of execution of this <tt>load</tt> with other <a
4957 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4958
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4959<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4960 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4961 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4962 not valid on <code>load</code> instructions. Atomic loads produce <a
4963 href="#memorymodel">defined</a> results when they may see multiple atomic
4964 stores. The type of the pointee must be an integer type whose bit width
4965 is a power of two greater than or equal to eight and less than or equal
4966 to a target-specific size limit. <code>align</code> must be explicitly
4967 specified on atomic loads, and the load has undefined behavior if the
4968 alignment is not set to a value which is at least the size in bytes of
4969 the pointee. <code>!nontemporal</code> does not have any defined semantics
4970 for atomic loads.</p>
4971
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4972<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4973 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]4974 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4975 alignment for the target. It is the responsibility of the code emitter to
4976 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4977 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4978 produce less efficient code. An alignment of 1 is always safe.</p>
4979
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4980<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4981 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4982 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4983 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4984 and code generator that this load is not expected to be reused in the cache.
4985 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4986 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4987
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]4988<p>The optional <tt>!invariant.load</tt> metadata must reference a single
4989 metatadata name &lt;index&gt; corresponding to a metadata node with no
4990 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
4991 instruction tells the optimizer and code generator that this load address
4992 points to memory which does not change value during program execution.
4993 The optimizer may then move this load around, for example, by hoisting it
4994 out of loops using loop invariant code motion.</p>
4995
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4996<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4997<p>The location of memory pointed to is loaded. If the value being loaded is of
4998 scalar type then the number of bytes read does not exceed the minimum number
4999 of bytes needed to hold all bits of the type. For example, loading an
5000 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5001 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5002 is undefined if the value was not originally written using a store of the
5003 same type.</p>
5004
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5005<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5006<pre>
5007 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5008 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5009 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5010</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5011
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5012</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5013
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5014<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5015<h4>
5016 <a name="i_store">'<tt>store</tt>' Instruction</a>
5017</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5018
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5019<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5020
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5021<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5022<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5023 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>
5024 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]5025</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5026
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5027<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5028<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5029
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5030<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5031<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5032 and an address at which to store it. The type of the
5033 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5034 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]5035 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5036 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5037 order of execution of this <tt>store</tt> with other <a
5038 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5039
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]5040<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5041 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5042 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5043 valid on <code>store</code> instructions. Atomic loads produce <a
5044 href="#memorymodel">defined</a> results when they may see multiple atomic
5045 stores. The type of the pointee must be an integer type whose bit width
5046 is a power of two greater than or equal to eight and less than or equal
5047 to a target-specific size limit. <code>align</code> must be explicitly
5048 specified on atomic stores, and the store has undefined behavior if the
5049 alignment is not set to a value which is at least the size in bytes of
5050 the pointee. <code>!nontemporal</code> does not have any defined semantics
5051 for atomic stores.</p>
5052
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5053<p>The optional constant "align" argument specifies the alignment of the
5054 operation (that is, the alignment of the memory address). A value of 0 or an
5055 omitted "align" argument means that the operation has the preferential
5056 alignment for the target. It is the responsibility of the code emitter to
5057 ensure that the alignment information is correct. Overestimating the
5058 alignment results in an undefined behavior. Underestimating the alignment may
5059 produce less efficient code. An alignment of 1 is always safe.</p>
5060
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5061<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5062 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5063 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5064 instruction tells the optimizer and code generator that this load is
5065 not expected to be reused in the cache. The code generator may
5066 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5067 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]5068
5069
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5070<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5072 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5073 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5074 does not exceed the minimum number of bytes needed to hold all bits of the
5075 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5076 writing a value of a type like <tt>i20</tt> with a size that is not an
5077 integral number of bytes, it is unspecified what happens to the extra bits
5078 that do not belong to the type, but they will typically be overwritten.</p>
5079
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5080<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5081<pre>
5082 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]5083 store i32 3, i32* %ptr <i>; yields {void}</i>
5084 %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]5085</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5087</div>
5088
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]5089<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5090<h4>
5091<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5092</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5093
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5094<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5095
5096<h5>Syntax:</h5>
5097<pre>
5098 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5099</pre>
5100
5101<h5>Overview:</h5>
5102<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5103between operations.</p>
5104
5105<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5106href="#ordering">ordering</a> argument which defines what
5107<i>synchronizes-with</i> edges they add. They can only be given
5108<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5109<code>seq_cst</code> orderings.</p>
5110
5111<h5>Semantics:</h5>
5112<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5113semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5114<code>acquire</code> ordering semantics if and only if there exist atomic
5115operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5116<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5117<var>X</var> modifies <var>M</var> (either directly or through some side effect
5118of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5119<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5120<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5121than an explicit <code>fence</code>, one (but not both) of the atomic operations
5122<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5123<code>acquire</code> (resp.) ordering constraint and still
5124<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5125<i>happens-before</i> edge.</p>
5126
5127<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5128having both <code>acquire</code> and <code>release</code> semantics specified
5129above, participates in the global program order of other <code>seq_cst</code>
5130operations and/or fences.</p>
5131
5132<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5133specifies that the fence only synchronizes with other fences in the same
5134thread. (This is useful for interacting with signal handlers.)</p>
5135
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5136<h5>Example:</h5>
5137<pre>
5138 fence acquire <i>; yields {void}</i>
5139 fence singlethread seq_cst <i>; yields {void}</i>
5140</pre>
5141
5142</div>
5143
5144<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5145<h4>
5146<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5147</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5148
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5149<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5150
5151<h5>Syntax:</h5>
5152<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5153 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]5154</pre>
5155
5156<h5>Overview:</h5>
5157<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5158It loads a value in memory and compares it to a given value. If they are
5159equal, it stores a new value into the memory.</p>
5160
5161<h5>Arguments:</h5>
5162<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5163address to operate on, a value to compare to the value currently be at that
5164address, and a new value to place at that address if the compared values are
5165equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5166bit width is a power of two greater than or equal to eight and less than
5167or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5168'<var>&lt;new&gt;</var>' must have the same type, and the type of
5169'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5170<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5171optimizer is not allowed to modify the number or order of execution
5172of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5173operations</a>.</p>
5174
5175<!-- FIXME: Extend allowed types. -->
5176
5177<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5178<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5179
5180<p>The optional "<code>singlethread</code>" argument declares that the
5181<code>cmpxchg</code> is only atomic with respect to code (usually signal
5182handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5183cmpxchg is atomic with respect to all other code in the system.</p>
5184
5185<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5186the size in memory of the operand.
5187
5188<h5>Semantics:</h5>
5189<p>The contents of memory at the location specified by the
5190'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5191'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5192'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5193is returned.
5194
5195<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5196purpose of identifying <a href="#release_sequence">release sequences</a>. A
5197failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5198parameter determined by dropping any <code>release</code> part of the
5199<code>cmpxchg</code>'s ordering.</p>
5200
5201<!--
5202FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5203optimization work on ARM.)
5204
5205FIXME: Is a weaker ordering constraint on failure helpful in practice?
5206-->
5207
5208<h5>Example:</h5>
5209<pre>
5210entry:
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5211 %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]5212 <a href="#i_br">br</a> label %loop
5213
5214loop:
5215 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5216 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5217 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5218 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5219 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5220
5221done:
5222 ...
5223</pre>
5224
5225</div>
5226
5227<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5228<h4>
5229<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5230</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5231
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5232<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5233
5234<h5>Syntax:</h5>
5235<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]5236 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]5237</pre>
5238
5239<h5>Overview:</h5>
5240<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5241
5242<h5>Arguments:</h5>
5243<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5244operation to apply, an address whose value to modify, an argument to the
5245operation. The operation must be one of the following keywords:</p>
5246<ul>
5247 <li>xchg</li>
5248 <li>add</li>
5249 <li>sub</li>
5250 <li>and</li>
5251 <li>nand</li>
5252 <li>or</li>
5253 <li>xor</li>
5254 <li>max</li>
5255 <li>min</li>
5256 <li>umax</li>
5257 <li>umin</li>
5258</ul>
5259
5260<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5261bit width is a power of two greater than or equal to eight and less than
5262or equal to a target-specific size limit. The type of the
5263'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5264If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5265optimizer is not allowed to modify the number or order of execution of this
5266<code>atomicrmw</code> with other <a href="#volatile">volatile
5267 operations</a>.</p>
5268
5269<!-- FIXME: Extend allowed types. -->
5270
5271<h5>Semantics:</h5>
5272<p>The contents of memory at the location specified by the
5273'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5274back. The original value at the location is returned. The modification is
5275specified by the <var>operation</var> argument:</p>
5276
5277<ul>
5278 <li>xchg: <code>*ptr = val</code></li>
5279 <li>add: <code>*ptr = *ptr + val</code></li>
5280 <li>sub: <code>*ptr = *ptr - val</code></li>
5281 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5282 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5283 <li>or: <code>*ptr = *ptr | val</code></li>
5284 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5285 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5286 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5287 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5288 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5289</ul>
5290
5291<h5>Example:</h5>
5292<pre>
5293 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5294</pre>
5295
5296</div>
5297
5298<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5299<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5300 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5301</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5302
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5303<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5304
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5305<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5306<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5307 &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]5308 &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]5309 &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]5310</pre>
5311
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5312<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5313<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5314 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5315 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5316
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5317<h5>Arguments:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5318<p>The first argument is always a pointer or a vector of pointers,
5319 and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5320 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5321 elements of the aggregate object are indexed. The interpretation of each
5322 index is dependent on the type being indexed into. The first index always
5323 indexes the pointer value given as the first argument, the second index
5324 indexes a value of the type pointed to (not necessarily the value directly
5325 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5326 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5327 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5328 can never be pointers, since that would require loading the pointer before
5329 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5330
5331<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]5332 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5333 integer <b>constants</b> are allowed. When indexing into an array, pointer
5334 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]5335 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5336
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5337<p>For example, let's consider a C code fragment and how it gets compiled to
5338 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5339
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5340<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5341struct RT {
5342 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5343 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5344 char C;
5345};
5346struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5347 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5348 double Y;
5349 struct RT Z;
5350};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5351
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5352int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5353 return &amp;s[1].Z.B[5][13];
5354}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5355</pre>
5356
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5357<p>The LLVM code generated by Clang is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5358
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5359<pre class="doc_code">
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5360%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5361%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5362
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5363define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5364entry:
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5365 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5366 ret i32* %arrayidx
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5367}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5368</pre>
5369
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5370<h5>Semantics:</h5>
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5371<p>In the example above, the first index is indexing into the
5372 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5373 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5374 structure. The second index indexes into the third element of the structure,
5375 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5376 type, another structure. The third index indexes into the second element of
5377 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5378 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5379 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5380 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5381
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5382<p>Note that it is perfectly legal to index partially through a structure,
5383 returning a pointer to an inner element. Because of this, the LLVM code for
5384 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5385
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5386<pre class="doc_code">
5387define i32* @foo(%struct.ST* %s) {
5388 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5389 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5390 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5391 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5392 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5393 ret i32* %t5
5394}
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5395</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5396
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5397<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]5398 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5399 base pointer is not an <i>in bounds</i> address of an allocated object,
5400 or if any of the addresses that would be formed by successive addition of
5401 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5402 precise signed arithmetic are not an <i>in bounds</i> address of that
5403 allocated object. The <i>in bounds</i> addresses for an allocated object
5404 are all the addresses that point into the object, plus the address one
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5405 byte past the end.
5406 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5407 applies to each of the computations element-wise. </p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5408
5409<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]5410 the base address with silently-wrapping two's complement arithmetic. If the
5411 offsets have a different width from the pointer, they are sign-extended or
5412 truncated to the width of the pointer. The result value of the
5413 <tt>getelementptr</tt> may be outside the object pointed to by the base
5414 pointer. The result value may not necessarily be used to access memory
5415 though, even if it happens to point into allocated storage. See the
5416 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5417 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5418
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5419<p>The getelementptr instruction is often confusing. For some more insight into
5420 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5421
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5422<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5423<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5424 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5425 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5426 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5427 %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]5428 <i>; yields i8*:eptr</i>
5429 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5430 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5431 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5432</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5433
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5434<p>In cases where the pointer argument is a vector of pointers, only a
5435 single index may be used, and the number of vector elements has to be
5436 the same. For example: </p>
5437<pre class="doc_code">
5438 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5439</pre>
5440
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5441</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5443</div>
5444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5445<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5446<h3>
5447 <a name="convertops">Conversion Operations</a>
5448</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5450<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5451
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5452<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5453 which all take a single operand and a type. They perform various bit
5454 conversions on the operand.</p>
5455
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5456<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5457<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5458 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5459</h4>
5460
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5461<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5462
5463<h5>Syntax:</h5>
5464<pre>
5465 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5466</pre>
5467
5468<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5469<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5470 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5471
5472<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5473<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5474 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5475 of the same number of integers.
5476 The bit size of the <tt>value</tt> must be larger than
5477 the bit size of the destination type, <tt>ty2</tt>.
5478 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5479
5480<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5481<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5482 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5483 source size must be larger than the destination size, <tt>trunc</tt> cannot
5484 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5485
5486<h5>Example:</h5>
5487<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5488 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5489 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5490 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5491 %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]5492</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5493
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5494</div>
5495
5496<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5497<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5498 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5499</h4>
5500
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5501<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5502
5503<h5>Syntax:</h5>
5504<pre>
5505 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5506</pre>
5507
5508<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5509<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5510 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5511
5512
5513<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5514<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5515 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5516 of the same number of integers.
5517 The bit size of the <tt>value</tt> must be smaller than
5518 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5519 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5520
5521<h5>Semantics:</h5>
5522<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]5523 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5524
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5525<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]5526
5527<h5>Example:</h5>
5528<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5529 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5530 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5531 %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]5532</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5533
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5534</div>
5535
5536<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5537<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5538 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5539</h4>
5540
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5541<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5542
5543<h5>Syntax:</h5>
5544<pre>
5545 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5546</pre>
5547
5548<h5>Overview:</h5>
5549<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5550
5551<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5552<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5553 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5554 of the same number of integers.
5555 The bit size of the <tt>value</tt> must be smaller than
5556 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5557 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5558
5559<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5560<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5561 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5562 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5563
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5564<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]5565
5566<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5567<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5568 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5569 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5570 %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]5571</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5572
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5573</div>
5574
5575<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5576<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5577 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5578</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5579
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5580<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5581
5582<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5583<pre>
5584 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5585</pre>
5586
5587<h5>Overview:</h5>
5588<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5589 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5590
5591<h5>Arguments:</h5>
5592<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5593 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5594 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]5595 <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]5596 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5597
5598<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5599<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5600 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5601 <a href="#t_floating">floating point</a> type. If the value cannot fit
5602 within the destination type, <tt>ty2</tt>, then the results are
5603 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5604
5605<h5>Example:</h5>
5606<pre>
5607 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5608 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5609</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5610
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5611</div>
5612
5613<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5614<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5615 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5616</h4>
5617
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5618<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5619
5620<h5>Syntax:</h5>
5621<pre>
5622 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5623</pre>
5624
5625<h5>Overview:</h5>
5626<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]5627 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5628
5629<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5630<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5631 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5632 a <a href="#t_floating">floating point</a> type to cast it to. The source
5633 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5634
5635<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5636<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5637 <a href="#t_floating">floating point</a> type to a larger
5638 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5639 used to make a <i>no-op cast</i> because it always changes bits. Use
5640 <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]5641
5642<h5>Example:</h5>
5643<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5644 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5645 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5646</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5647
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5648</div>
5649
5650<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5651<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5652 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5653</h4>
5654
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5655<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5656
5657<h5>Syntax:</h5>
5658<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5659 &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]5660</pre>
5661
5662<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5663<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5664 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5665
5666<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5667<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5668 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5669 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5670 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5671 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5672
5673<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5674<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5675 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5676 towards zero) unsigned integer value. If the value cannot fit
5677 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5678
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5679<h5>Example:</h5>
5680<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5681 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5682 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5683 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5684</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5685
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5686</div>
5687
5688<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5689<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5690 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5691</h4>
5692
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5693<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5694
5695<h5>Syntax:</h5>
5696<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5697 &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]5698</pre>
5699
5700<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5701<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5702 <a href="#t_floating">floating point</a> <tt>value</tt> to
5703 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5704
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5705<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5707 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5708 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5709 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5710 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5711
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5712<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5713<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5714 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5715 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5716 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5717
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5718<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5719<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5720 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5721 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5722 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5723</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5725</div>
5726
5727<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5728<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5729 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5730</h4>
5731
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5732<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5733
5734<h5>Syntax:</h5>
5735<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5736 &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]5737</pre>
5738
5739<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5740<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5741 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5742
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5743<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5744<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]5745 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5746 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5747 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5748 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5749
5750<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5751<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5752 integer quantity and converts it to the corresponding floating point
5753 value. If the value cannot fit in the floating point value, the results are
5754 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5755
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5756<h5>Example:</h5>
5757<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5758 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5759 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5760</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5762</div>
5763
5764<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5765<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5766 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5767</h4>
5768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5769<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5770
5771<h5>Syntax:</h5>
5772<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5773 &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]5774</pre>
5775
5776<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5777<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5778 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5781<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]5782 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5783 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5784 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5785 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5786
5787<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5788<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5789 quantity and converts it to the corresponding floating point value. If the
5790 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5791
5792<h5>Example:</h5>
5793<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5794 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5795 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5796</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5797
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5798</div>
5799
5800<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5801<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5802 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5803</h4>
5804
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5805<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5806
5807<h5>Syntax:</h5>
5808<pre>
5809 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5810</pre>
5811
5812<h5>Overview:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5813<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5814 pointers <tt>value</tt> to
5815 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5816
5817<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5818<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5819 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5820 pointers, and a type to cast it to
5821 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5822 of integers type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5823
5824<h5>Semantics:</h5>
5825<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5826 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5827 truncating or zero extending that value to the size of the integer type. If
5828 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5829 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5830 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5831 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5832
5833<h5>Example:</h5>
5834<pre>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5835 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5836 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5837 %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]5838</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5839
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5840</div>
5841
5842<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5843<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5844 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5845</h4>
5846
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5847<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5848
5849<h5>Syntax:</h5>
5850<pre>
5851 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5852</pre>
5853
5854<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5856 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5857
5858<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5859<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5860 value to cast, and a type to cast it to, which must be a
5861 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5862
5863<h5>Semantics:</h5>
5864<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5866 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5867 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5868 than the size of a pointer then a zero extension is done. If they are the
5869 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5870
5871<h5>Example:</h5>
5872<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5873 %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]5874 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5875 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5876 %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]5877</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5878
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5879</div>
5880
5881<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5882<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5883 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5884</h4>
5885
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5886<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5887
5888<h5>Syntax:</h5>
5889<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5890 &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]5891</pre>
5892
5893<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5894<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5896
5897<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5898<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5899 non-aggregate first class value, and a type to cast it to, which must also be
5900 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5901 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5902 identical. If the source type is a pointer, the destination type must also be
5903 a pointer. This instruction supports bitwise conversion of vectors to
5904 integers and to vectors of other types (as long as they have the same
5905 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5906
5907<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5908<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5909 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5910 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5911 stored to memory and read back as type <tt>ty2</tt>.
5912 Pointer (or vector of pointers) types may only be converted to other pointer
5913 (or vector of pointers) types with this instruction. To convert
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5914 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5915 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5916
5917<h5>Example:</h5>
5918<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5919 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5920 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5921 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5922 %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]5923</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5924
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5925</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5926
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5927</div>
5928
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5929<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5930<h3>
5931 <a name="otherops">Other Operations</a>
5932</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5933
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5934<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5935
5936<p>The instructions in this category are the "miscellaneous" instructions, which
5937 defy better classification.</p>
5938
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5939<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5940<h4>
5941 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5942</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5944<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5945
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5946<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5947<pre>
5948 &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]5949</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5951<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5952<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5953 boolean values based on comparison of its two integer, integer vector,
5954 pointer, or pointer vector operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5955
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5956<h5>Arguments:</h5>
5957<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5958 the condition code indicating the kind of comparison to perform. It is not a
5959 value, just a keyword. The possible condition code are:</p>
5960
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5961<ol>
5962 <li><tt>eq</tt>: equal</li>
5963 <li><tt>ne</tt>: not equal </li>
5964 <li><tt>ugt</tt>: unsigned greater than</li>
5965 <li><tt>uge</tt>: unsigned greater or equal</li>
5966 <li><tt>ult</tt>: unsigned less than</li>
5967 <li><tt>ule</tt>: unsigned less or equal</li>
5968 <li><tt>sgt</tt>: signed greater than</li>
5969 <li><tt>sge</tt>: signed greater or equal</li>
5970 <li><tt>slt</tt>: signed less than</li>
5971 <li><tt>sle</tt>: signed less or equal</li>
5972</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5973
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5974<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5975 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5976 typed. They must also be identical types.</p>
5977
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5978<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5979<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5980 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5981 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]5982 result, as follows:</p>
5983
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5984<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5985 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5986 <tt>false</tt> otherwise. No sign interpretation is necessary or
5987 performed.</li>
5988
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5989 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5990 <tt>false</tt> otherwise. No sign interpretation is necessary or
5991 performed.</li>
5992
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5993 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5994 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5995
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5996 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5997 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5998 to <tt>op2</tt>.</li>
5999
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6000 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6002
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6003 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6005
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6006 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6008
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6009 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6010 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6011 to <tt>op2</tt>.</li>
6012
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6013 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6014 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6015
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6016 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017 <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]6018</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6019
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6020<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6021 values are compared as if they were integers.</p>
6022
6023<p>If the operands are integer vectors, then they are compared element by
6024 element. The result is an <tt>i1</tt> vector with the same number of elements
6025 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6026
6027<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028<pre>
6029 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6030 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6031 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6032 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6033 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6034 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6035</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6036
6037<p>Note that the code generator does not yet support vector types with
6038 the <tt>icmp</tt> instruction.</p>
6039
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6040</div>
6041
6042<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6043<h4>
6044 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6045</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6046
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6047<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6048
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6049<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6050<pre>
6051 &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]6052</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6054<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6055<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6056 values based on comparison of its operands.</p>
6057
6058<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]6059(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6060
6061<p>If the operands are floating point vectors, then the result type is a vector
6062 of boolean with the same number of elements as the operands being
6063 compared.</p>
6064
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6065<h5>Arguments:</h5>
6066<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6067 the condition code indicating the kind of comparison to perform. It is not a
6068 value, just a keyword. The possible condition code are:</p>
6069
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6070<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6071 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6072 <li><tt>oeq</tt>: ordered and equal</li>
6073 <li><tt>ogt</tt>: ordered and greater than </li>
6074 <li><tt>oge</tt>: ordered and greater than or equal</li>
6075 <li><tt>olt</tt>: ordered and less than </li>
6076 <li><tt>ole</tt>: ordered and less than or equal</li>
6077 <li><tt>one</tt>: ordered and not equal</li>
6078 <li><tt>ord</tt>: ordered (no nans)</li>
6079 <li><tt>ueq</tt>: unordered or equal</li>
6080 <li><tt>ugt</tt>: unordered or greater than </li>
6081 <li><tt>uge</tt>: unordered or greater than or equal</li>
6082 <li><tt>ult</tt>: unordered or less than </li>
6083 <li><tt>ule</tt>: unordered or less than or equal</li>
6084 <li><tt>une</tt>: unordered or not equal</li>
6085 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6086 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6087</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6088
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6089<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6090 <i>unordered</i> means that either operand may be a QNAN.</p>
6091
6092<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6093 a <a href="#t_floating">floating point</a> type or
6094 a <a href="#t_vector">vector</a> of floating point type. They must have
6095 identical types.</p>
6096
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6097<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]6098<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6099 according to the condition code given as <tt>cond</tt>. If the operands are
6100 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]6101 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6102 follows:</p>
6103
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6104<ol>
6105 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6106
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6107 <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]6108 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6109
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6110 <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]6111 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6112
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6113 <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]6114 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6115
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6116 <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]6117 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6118
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6119 <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]6120 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6121
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6122 <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]6123 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6124
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6125 <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]6126
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6127 <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]6128 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6129
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6130 <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]6131 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6132
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6133 <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]6134 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6135
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6136 <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]6137 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6138
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6139 <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]6140 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6141
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6142 <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]6143 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6144
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6145 <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]6146
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6147 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6148</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6149
6150<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6151<pre>
6152 &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]6153 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6154 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6155 &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]6156</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6157
6158<p>Note that the code generator does not yet support vector types with
6159 the <tt>fcmp</tt> instruction.</p>
6160
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6161</div>
6162
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6163<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6164<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6165 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6166</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6167
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6168<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6169
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6170<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6171<pre>
6172 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6173</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6174
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6175<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6176<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6177 SSA graph representing the function.</p>
6178
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6179<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6180<p>The type of the incoming values is specified with the first type field. After
6181 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6182 one pair for each predecessor basic block of the current block. Only values
6183 of <a href="#t_firstclass">first class</a> type may be used as the value
6184 arguments to the PHI node. Only labels may be used as the label
6185 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6186
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6187<p>There must be no non-phi instructions between the start of a basic block and
6188 the PHI instructions: i.e. PHI instructions must be first in a basic
6189 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6190
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6191<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6192 occur on the edge from the corresponding predecessor block to the current
6193 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6194 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]6195
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6196<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6197<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6198 specified by the pair corresponding to the predecessor basic block that
6199 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6200
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6201<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6202<pre>
6203Loop: ; Infinite loop that counts from 0 on up...
6204 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6205 %nextindvar = add i32 %indvar, 1
6206 br label %Loop
6207</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6208
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6209</div>
6210
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6211<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6212<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6213 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6214</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6215
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6216<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6217
6218<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6219<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6220 &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>
6221
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6222 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6223</pre>
6224
6225<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6226<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6227 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6228
6229
6230<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6231<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6232 values indicating the condition, and two values of the
6233 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6234 vectors and the condition is a scalar, then entire vectors are selected, not
6235 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6236
6237<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6238<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6239 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6240
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6241<p>If the condition is a vector of i1, then the value arguments must be vectors
6242 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6243
6244<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6245<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]6246 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6247</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6248
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6249</div>
6250
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]6251<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6252<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6253 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6254</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6255
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6256<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6257
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6258<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6259<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6260 &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]6261</pre>
6262
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6263<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6264<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6265
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6266<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6267<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6268
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6269<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6270 <li>The optional "tail" marker indicates that the callee function does not
6271 access any allocas or varargs in the caller. Note that calls may be
6272 marked "tail" even if they do not occur before
6273 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6274 present, the function call is eligible for tail call optimization,
6275 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6276 optimized into a jump</a>. The code generator may optimize calls marked
6277 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6278 sibling call optimization</a> when the caller and callee have
6279 matching signatures, or 2) forced tail call optimization when the
6280 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6281 <ul>
6282 <li>Caller and callee both have the calling
6283 convention <tt>fastcc</tt>.</li>
6284 <li>The call is in tail position (ret immediately follows call and ret
6285 uses value of call or is void).</li>
6286 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6287 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6288 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6289 constraints are met.</a></li>
6290 </ul>
6291 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6292
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6293 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6294 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6295 defaults to using C calling conventions. The calling convention of the
6296 call must match the calling convention of the target function, or else the
6297 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6298
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6299 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6300 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6301 '<tt>inreg</tt>' attributes are valid here.</li>
6302
6303 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6304 type of the return value. Functions that return no value are marked
6305 <tt><a href="#t_void">void</a></tt>.</li>
6306
6307 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6308 being invoked. The argument types must match the types implied by this
6309 signature. This type can be omitted if the function is not varargs and if
6310 the function type does not return a pointer to a function.</li>
6311
6312 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6313 be invoked. In most cases, this is a direct function invocation, but
6314 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6315 to function value.</li>
6316
6317 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6318 signature argument types and parameter attributes. All arguments must be
6319 of <a href="#t_firstclass">first class</a> type. If the function
6320 signature indicates the function accepts a variable number of arguments,
6321 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6322
6323 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6324 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6325 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6326</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6328<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6329<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6330 a specified function, with its incoming arguments bound to the specified
6331 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6332 function, control flow continues with the instruction after the function
6333 call, and the return value of the function is bound to the result
6334 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6336<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6337<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6338 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6339 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6340 %X = tail call i32 @foo() <i>; yields i32</i>
6341 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6342 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6343
6344 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6345 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6346 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6347 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6348 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6349 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6350</pre>
6351
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6352<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6353standard C99 library as being the C99 library functions, and may perform
6354optimizations or generate code for them under that assumption. This is
6355something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6356freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6357
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6358</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6359
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6360<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6361<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6362 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6363</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6364
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6365<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6366
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6367<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6368<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6369 &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]6370</pre>
6371
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6372<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6373<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6374 the "variable argument" area of a function call. It is used to implement the
6375 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6376
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6377<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6378<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6379 argument. It returns a value of the specified argument type and increments
6380 the <tt>va_list</tt> to point to the next argument. The actual type
6381 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6382
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6383<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6385 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6386 to the next argument. For more information, see the variable argument
6387 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6388
6389<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]6390 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6391 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6392
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6393<p><tt>va_arg</tt> is an LLVM instruction instead of
6394 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6395 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6396
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6397<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6398<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6399
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6400<p>Note that the code generator does not yet fully support va_arg on many
6401 targets. Also, it does not currently support va_arg with aggregate types on
6402 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6403
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6404</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6405
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6406<!-- _______________________________________________________________________ -->
6407<h4>
6408 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6409</h4>
6410
6411<div>
6412
6413<h5>Syntax:</h5>
6414<pre>
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6415 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6416 &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]6417
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6418 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6419 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6420</pre>
6421
6422<h5>Overview:</h5>
6423<p>The '<tt>landingpad</tt>' instruction is used by
6424 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6425 system</a> to specify that a basic block is a landing pad &mdash; one where
6426 the exception lands, and corresponds to the code found in the
6427 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6428 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6429 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6430 type <tt>resultty</tt>.</p>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6431
6432<h5>Arguments:</h5>
6433<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6434 function associated with the unwinding mechanism. The optional
6435 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6436
6437<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6438 or <tt>filter</tt> &mdash; and contains the global variable representing the
6439 "type" that may be caught or filtered respectively. Unlike the
6440 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6441 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6442 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6443 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6444
6445<h5>Semantics:</h5>
6446<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6447 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6448 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6449 calling conventions, how the personality function results are represented in
6450 LLVM IR is target specific.</p>
6451
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6452<p>The clauses are applied in order from top to bottom. If two
6453 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6454 clauses from the calling function are appended to the list of clauses.
6455 When the call stack is being unwound due to an exception being thrown, the
6456 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6457 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6458 unwinding continues further up the call stack.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6459
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6460<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6461
6462<ul>
6463 <li>A landing pad block is a basic block which is the unwind destination of an
6464 '<tt>invoke</tt>' instruction.</li>
6465 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6466 first non-PHI instruction.</li>
6467 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6468 pad block.</li>
6469 <li>A basic block that is not a landing pad block may not include a
6470 '<tt>landingpad</tt>' instruction.</li>
6471 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6472 personality function.</li>
6473</ul>
6474
6475<h5>Example:</h5>
6476<pre>
6477 ;; A landing pad which can catch an integer.
6478 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6479 catch i8** @_ZTIi
6480 ;; A landing pad that is a cleanup.
6481 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6482 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6483 ;; A landing pad which can catch an integer and can only throw a double.
6484 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6485 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6486 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6487</pre>
6488
6489</div>
6490
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6491</div>
6492
6493</div>
6494
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6495<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6496<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6497<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6498
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6499<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6500
6501<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6502 well known names and semantics and are required to follow certain
6503 restrictions. Overall, these intrinsics represent an extension mechanism for
6504 the LLVM language that does not require changing all of the transformations
6505 in LLVM when adding to the language (or the bitcode reader/writer, the
6506 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6507
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6508<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6509 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6510 begin with this prefix. Intrinsic functions must always be external
6511 functions: you cannot define the body of intrinsic functions. Intrinsic
6512 functions may only be used in call or invoke instructions: it is illegal to
6513 take the address of an intrinsic function. Additionally, because intrinsic
6514 functions are part of the LLVM language, it is required if any are added that
6515 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6516
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6517<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6518 family of functions that perform the same operation but on different data
6519 types. Because LLVM can represent over 8 million different integer types,
6520 overloading is used commonly to allow an intrinsic function to operate on any
6521 integer type. One or more of the argument types or the result type can be
6522 overloaded to accept any integer type. Argument types may also be defined as
6523 exactly matching a previous argument's type or the result type. This allows
6524 an intrinsic function which accepts multiple arguments, but needs all of them
6525 to be of the same type, to only be overloaded with respect to a single
6526 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6527
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6528<p>Overloaded intrinsics will have the names of its overloaded argument types
6529 encoded into its function name, each preceded by a period. Only those types
6530 which are overloaded result in a name suffix. Arguments whose type is matched
6531 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6532 can take an integer of any width and returns an integer of exactly the same
6533 integer width. This leads to a family of functions such as
6534 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6535 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6536 suffix is required. Because the argument's type is matched against the return
6537 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6538
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6539<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6540 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6541
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6542<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6543<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6544 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6545</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6546
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6547<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6548
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6549<p>Variable argument support is defined in LLVM with
6550 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6551 intrinsic functions. These functions are related to the similarly named
6552 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6553
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6554<p>All of these functions operate on arguments that use a target-specific value
6555 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6556 not define what this type is, so all transformations should be prepared to
6557 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6558
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6559<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]6560 instruction and the variable argument handling intrinsic functions are
6561 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6562
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6563<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6564define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6565 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6566 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6567 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6568 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6569
6570 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6571 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6572
6573 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6574 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6575 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6576 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6577 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6578
6579 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6580 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6581 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6582}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6583
6584declare void @llvm.va_start(i8*)
6585declare void @llvm.va_copy(i8*, i8*)
6586declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6587</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6588
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6589<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6590<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6591 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6592</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6593
6594
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6595<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6596
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6597<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6598<pre>
6599 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6600</pre>
6601
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6602<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6603<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6604 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]6605
6606<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6607<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]6608
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6609<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6610<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]6611 macro available in C. In a target-dependent way, it initializes
6612 the <tt>va_list</tt> element to which the argument points, so that the next
6613 call to <tt>va_arg</tt> will produce the first variable argument passed to
6614 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6615 need to know the last argument of the function as the compiler can figure
6616 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6617
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6618</div>
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_end">'<tt>llvm.va_end</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
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6625<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6626
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6627<h5>Syntax:</h5>
6628<pre>
6629 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6630</pre>
6631
6632<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6633<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634 which has been initialized previously
6635 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6636 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6637
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6638<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6639<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]6640
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6641<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6642<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]6643 macro available in C. In a target-dependent way, it destroys
6644 the <tt>va_list</tt> element to which the argument points. Calls
6645 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6646 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6647 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +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_copy">'<tt>llvm.va_copy</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 Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6657
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6658<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6659<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6660 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6661</pre>
6662
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6663<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6664<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6665 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6666
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6667<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6668<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]6669 The second argument is a pointer to a <tt>va_list</tt> element to copy
6670 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6671
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6672<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6673<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]6674 macro available in C. In a target-dependent way, it copies the
6675 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6676 element. This intrinsic is necessary because
6677 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6678 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +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
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6682</div>
6683
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6684<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6685<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6686 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6687</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6689<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6690
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6691<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6692Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6693intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6694roots on the stack</a>, as well as garbage collector implementations that
6695require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6696barriers. Front-ends for type-safe garbage collected languages should generate
6697these intrinsics to make use of the LLVM garbage collectors. For more details,
6698see <a href="GarbageCollection.html">Accurate Garbage Collection with
6699LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6700
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6701<p>The garbage collection intrinsics only operate on objects in the generic
6702 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6703
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6704<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6705<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6706 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6707</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6708
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6709<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6710
6711<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6712<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6713 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6714</pre>
6715
6716<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6717<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]6718 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6719
6720<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6721<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6722 root pointer. The second pointer (which must be either a constant or a
6723 global value address) contains the meta-data to be associated with the
6724 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6725
6726<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6727<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]6728 location. At compile-time, the code generator generates information to allow
6729 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6730 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6731 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6732
6733</div>
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_gcread">'<tt>llvm.gcread</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 i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6745</pre>
6746
6747<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6748<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6749 locations, allowing garbage collector implementations that require read
6750 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6751
6752<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6753<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]6754 allocated from the garbage collector. The first object is a pointer to the
6755 start of the referenced object, if needed by the language runtime (otherwise
6756 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6757
6758<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6759<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6760 instruction, but may be replaced with substantially more complex code by the
6761 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6762 may only be used in a function which <a href="#gc">specifies a GC
6763 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6764
6765</div>
6766
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6767<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6768<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6769 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6770</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6771
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6772<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6773
6774<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6775<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6776 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6777</pre>
6778
6779<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6780<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6781 locations, allowing garbage collector implementations that require write
6782 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6783
6784<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6785<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]6786 object to store it to, and the third is the address of the field of Obj to
6787 store to. If the runtime does not require a pointer to the object, Obj may
6788 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6789
6790<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6791<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6792 instruction, but may be replaced with substantially more complex code by the
6793 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6794 may only be used in a function which <a href="#gc">specifies a GC
6795 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6796
6797</div>
6798
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6799</div>
6800
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6801<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6802<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6803 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6804</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6805
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6806<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6807
6808<p>These intrinsics are provided by LLVM to expose special features that may
6809 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6810
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6811<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6812<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6813 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6814</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6815
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6816<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6817
6818<h5>Syntax:</h5>
6819<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6820 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6821</pre>
6822
6823<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6824<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6825 target-specific value indicating the return address of the current function
6826 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6827
6828<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6829<p>The argument to this intrinsic indicates which function to return the address
6830 for. Zero indicates the calling function, one indicates its caller, etc.
6831 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6832
6833<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6834<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6835 indicating the return address of the specified call frame, or zero if it
6836 cannot be identified. The value returned by this intrinsic is likely to be
6837 incorrect or 0 for arguments other than zero, so it should only be used for
6838 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6839
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6840<p>Note that calling this intrinsic does not prevent function inlining or other
6841 aggressive transformations, so the value returned may not be that of the
6842 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6843
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6844</div>
6845
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6846<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6847<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6848 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6849</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6850
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6851<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6852
6853<h5>Syntax:</h5>
6854<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6855 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6856</pre>
6857
6858<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6859<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6860 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6861
6862<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6863<p>The argument to this intrinsic indicates which function to return the frame
6864 pointer for. Zero indicates the calling function, one indicates its caller,
6865 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6866
6867<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6869 indicating the frame address of the specified call frame, or zero if it
6870 cannot be identified. The value returned by this intrinsic is likely to be
6871 incorrect or 0 for arguments other than zero, so it should only be used for
6872 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6874<p>Note that calling this intrinsic does not prevent function inlining or other
6875 aggressive transformations, so the value returned may not be that of the
6876 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6877
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6878</div>
6879
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6880<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6881<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6882 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6883</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6884
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6885<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6886
6887<h5>Syntax:</h5>
6888<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6889 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6890</pre>
6891
6892<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6893<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6894 of the function stack, for use
6895 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6896 useful for implementing language features like scoped automatic variable
6897 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6898
6899<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6900<p>This intrinsic returns a opaque pointer value that can be passed
6901 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6902 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6903 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6904 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6905 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6906 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6907
6908</div>
6909
6910<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6911<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6912 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6913</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6914
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6915<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6916
6917<h5>Syntax:</h5>
6918<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6919 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6920</pre>
6921
6922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6924 the function stack to the state it was in when the
6925 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6926 executed. This is useful for implementing language features like scoped
6927 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6928
6929<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6930<p>See the description
6931 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6932
6933</div>
6934
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6935<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6936<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6937 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6938</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6939
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6940<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6941
6942<h5>Syntax:</h5>
6943<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6944 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]6945</pre>
6946
6947<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6949 insert a prefetch instruction if supported; otherwise, it is a noop.
6950 Prefetches have no effect on the behavior of the program but can change its
6951 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6952
6953<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6954<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6955 specifier determining if the fetch should be for a read (0) or write (1),
6956 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6957 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6958 specifies whether the prefetch is performed on the data (1) or instruction (0)
6959 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6960 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6961
6962<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6963<p>This intrinsic does not modify the behavior of the program. In particular,
6964 prefetches cannot trap and do not produce a value. On targets that support
6965 this intrinsic, the prefetch can provide hints to the processor cache for
6966 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6967
6968</div>
6969
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6970<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6971<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6972 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6973</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6974
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6975<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6976
6977<h5>Syntax:</h5>
6978<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6979 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6980</pre>
6981
6982<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6983<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6984 Counter (PC) in a region of code to simulators and other tools. The method
6985 is target specific, but it is expected that the marker will use exported
6986 symbols to transmit the PC of the marker. The marker makes no guarantees
6987 that it will remain with any specific instruction after optimizations. It is
6988 possible that the presence of a marker will inhibit optimizations. The
6989 intended use is to be inserted after optimizations to allow correlations of
6990 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6991
6992<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6993<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6994
6995<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6996<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6997 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6998
6999</div>
7000
Andrew Lenharth01aa5632005-11-11 16:47:30 +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_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7004</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7005
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7006<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7007
7008<h5>Syntax:</h5>
7009<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7010 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +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.readcyclecounter</tt>' intrinsic provides access to the cycle
7015 counter register (or similar low latency, high accuracy clocks) on those
7016 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7017 should map to RPCC. As the backing counters overflow quickly (on the order
7018 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7019
7020<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021<p>When directly supported, reading the cycle counter should not modify any
7022 memory. Implementations are allowed to either return a application specific
7023 value or a system wide value. On backends without support, this is lowered
7024 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]7025
7026</div>
7027
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7028</div>
7029
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7030<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7031<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7032 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7033</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7034
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7035<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7036
7037<p>LLVM provides intrinsics for a few important standard C library functions.
7038 These intrinsics allow source-language front-ends to pass information about
7039 the alignment of the pointer arguments to the code generator, providing
7040 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7041
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7042<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7043<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7044 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7045</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7046
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7047<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7048
7049<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7050<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]7051 integer bit width and for different address spaces. Not all targets support
7052 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7053
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7054<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7055 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]7056 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7057 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]7058 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7059</pre>
7060
7061<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7062<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7063 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7064
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7065<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7066 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7067 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7068
7069<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7070
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7071<p>The first argument is a pointer to the destination, the second is a pointer
7072 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7073 number of bytes to copy, the fourth argument is the alignment of the
7074 source and destination locations, and the fifth is a boolean indicating a
7075 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7076
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7077<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]7078 then the caller guarantees that both the source and destination pointers are
7079 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7080
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7081<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7082 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7083 The detailed access behavior is not very cleanly specified and it is unwise
7084 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7085
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7086<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7089 source location to the destination location, which are not allowed to
7090 overlap. It copies "len" bytes of memory over. If the argument is known to
7091 be aligned to some boundary, this can be specified as the fourth argument,
7092 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7093
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]7094</div>
7095
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7096<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7097<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7098 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7099</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7100
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7101<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7102
7103<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7104<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]7105 width and for different address space. Not all targets support all bit
7106 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7107
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7108<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7109 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]7110 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7111 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]7112 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7113</pre>
7114
7115<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7116<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7117 source location to the destination location. It is similar to the
7118 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7119 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7120
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7121<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7122 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7123 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7124
7125<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7126
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7127<p>The first argument is a pointer to the destination, the second is a pointer
7128 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7129 number of bytes to copy, the fourth argument is the alignment of the
7130 source and destination locations, and the fifth is a boolean indicating a
7131 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7132
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7133<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]7134 then the caller guarantees that the source and destination pointers are
7135 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7136
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7137<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7138 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7139 The detailed access behavior is not very cleanly specified and it is unwise
7140 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7141
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7142<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7143
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7144<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7145 source location to the destination location, which may overlap. It copies
7146 "len" bytes of memory over. If the argument is known to be aligned to some
7147 boundary, this can be specified as the fourth argument, otherwise it should
7148 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7149
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7150</div>
7151
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7152<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7153<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7154 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7155</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7156
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7157<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7158
7159<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7160<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]7161 width and for different address spaces. However, not all targets support all
7162 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7163
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7164<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7165 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7166 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7167 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7168 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7169</pre>
7170
7171<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7172<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7173 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7174
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7175<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7176 intrinsic does not return a value and takes extra alignment/volatile
7177 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7178
7179<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7180<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]7181 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7182 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7183 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7184
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7185<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]7186 then the caller guarantees that the destination pointer is aligned to that
7187 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7188
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7189<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7190 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7191 The detailed access behavior is not very cleanly specified and it is unwise
7192 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7193
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7194<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7195<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7196 at the destination location. If the argument is known to be aligned to some
7197 boundary, this can be specified as the fourth argument, otherwise it should
7198 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7199
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7200</div>
7201
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7202<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7203<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7204 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7205</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7206
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7207<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7208
7209<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7210<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7211 floating point or vector of floating point type. Not all targets support all
7212 types however.</p>
7213
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7214<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7215 declare float @llvm.sqrt.f32(float %Val)
7216 declare double @llvm.sqrt.f64(double %Val)
7217 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7218 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7219 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7220</pre>
7221
7222<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7223<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7224 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7225 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7226 behavior for negative numbers other than -0.0 (which allows for better
7227 optimization, because there is no need to worry about errno being
7228 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]7229
7230<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7231<p>The argument and return value are floating point numbers of the same
7232 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7233
7234<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7235<p>This function returns the sqrt of the specified operand if it is a
7236 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7237
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7238</div>
7239
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7240<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7241<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7242 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7243</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7244
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7245<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7246
7247<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7248<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7249 floating point or vector of floating point type. Not all targets support all
7250 types however.</p>
7251
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7252<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7253 declare float @llvm.powi.f32(float %Val, i32 %power)
7254 declare double @llvm.powi.f64(double %Val, i32 %power)
7255 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7256 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7257 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7258</pre>
7259
7260<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7261<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7262 specified (positive or negative) power. The order of evaluation of
7263 multiplications is not defined. When a vector of floating point type is
7264 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7265
7266<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7267<p>The second argument is an integer power, and the first is a value to raise to
7268 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7269
7270<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7271<p>This function returns the first value raised to the second power with an
7272 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7273
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7274</div>
7275
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7276<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7277<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7278 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7279</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7280
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7281<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7282
7283<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7284<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7285 floating point or vector of floating point type. Not all targets support all
7286 types however.</p>
7287
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7288<pre>
7289 declare float @llvm.sin.f32(float %Val)
7290 declare double @llvm.sin.f64(double %Val)
7291 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7292 declare fp128 @llvm.sin.f128(fp128 %Val)
7293 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7294</pre>
7295
7296<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7297<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7298
7299<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7300<p>The argument and return value are floating point numbers of the same
7301 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7302
7303<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7304<p>This function returns the sine of the specified operand, returning the same
7305 values as the libm <tt>sin</tt> functions would, and handles error conditions
7306 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7307
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7308</div>
7309
7310<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7311<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7312 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7313</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7314
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7315<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7316
7317<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7318<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7319 floating point or vector of floating point type. Not all targets support all
7320 types however.</p>
7321
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7322<pre>
7323 declare float @llvm.cos.f32(float %Val)
7324 declare double @llvm.cos.f64(double %Val)
7325 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7326 declare fp128 @llvm.cos.f128(fp128 %Val)
7327 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7328</pre>
7329
7330<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7332
7333<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334<p>The argument and return value are floating point numbers of the same
7335 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7336
7337<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7338<p>This function returns the cosine of the specified operand, returning the same
7339 values as the libm <tt>cos</tt> functions would, and handles error conditions
7340 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7341
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7342</div>
7343
7344<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7345<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7346 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7347</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7348
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7349<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7350
7351<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7352<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7353 floating point or vector of floating point type. Not all targets support all
7354 types however.</p>
7355
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7356<pre>
7357 declare float @llvm.pow.f32(float %Val, float %Power)
7358 declare double @llvm.pow.f64(double %Val, double %Power)
7359 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7360 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7361 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7362</pre>
7363
7364<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7365<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7366 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7367
7368<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369<p>The second argument is a floating point power, and the first is a value to
7370 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7371
7372<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7373<p>This function returns the first value raised to the second power, returning
7374 the same values as the libm <tt>pow</tt> functions would, and handles error
7375 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7376
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7377</div>
7378
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7379<!-- _______________________________________________________________________ -->
7380<h4>
7381 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7382</h4>
7383
7384<div>
7385
7386<h5>Syntax:</h5>
7387<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7388 floating point or vector of floating point type. Not all targets support all
7389 types however.</p>
7390
7391<pre>
7392 declare float @llvm.exp.f32(float %Val)
7393 declare double @llvm.exp.f64(double %Val)
7394 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7395 declare fp128 @llvm.exp.f128(fp128 %Val)
7396 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7397</pre>
7398
7399<h5>Overview:</h5>
7400<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7401
7402<h5>Arguments:</h5>
7403<p>The argument and return value are floating point numbers of the same
7404 type.</p>
7405
7406<h5>Semantics:</h5>
7407<p>This function returns the same values as the libm <tt>exp</tt> functions
7408 would, and handles error conditions in the same way.</p>
7409
7410</div>
7411
7412<!-- _______________________________________________________________________ -->
7413<h4>
7414 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7415</h4>
7416
7417<div>
7418
7419<h5>Syntax:</h5>
7420<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7421 floating point or vector of floating point type. Not all targets support all
7422 types however.</p>
7423
7424<pre>
7425 declare float @llvm.log.f32(float %Val)
7426 declare double @llvm.log.f64(double %Val)
7427 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7428 declare fp128 @llvm.log.f128(fp128 %Val)
7429 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7430</pre>
7431
7432<h5>Overview:</h5>
7433<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7434
7435<h5>Arguments:</h5>
7436<p>The argument and return value are floating point numbers of the same
7437 type.</p>
7438
7439<h5>Semantics:</h5>
7440<p>This function returns the same values as the libm <tt>log</tt> functions
7441 would, and handles error conditions in the same way.</p>
7442
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7443</div>
7444
7445<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7446<h4>
7447 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7448</h4>
7449
7450<div>
7451
7452<h5>Syntax:</h5>
7453<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7454 floating point or vector of floating point type. Not all targets support all
7455 types however.</p>
7456
7457<pre>
7458 declare float @llvm.fma.f32(float %a, float %b, float %c)
7459 declare double @llvm.fma.f64(double %a, double %b, double %c)
7460 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7461 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7462 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7463</pre>
7464
7465<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7466<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7467 operation.</p>
7468
7469<h5>Arguments:</h5>
7470<p>The argument and return value are floating point numbers of the same
7471 type.</p>
7472
7473<h5>Semantics:</h5>
7474<p>This function returns the same values as the libm <tt>fma</tt> functions
7475 would.</p>
7476
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7477</div>
7478
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7479</div>
7480
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7481<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7482<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7483 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7484</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7485
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7486<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7487
7488<p>LLVM provides intrinsics for a few important bit manipulation operations.
7489 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7490
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7491<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7492<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7493 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7494</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7495
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7496<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7497
7498<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7499<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7500 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7501
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7502<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7503 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7504 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7505 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7506</pre>
7507
7508<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7509<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7510 values with an even number of bytes (positive multiple of 16 bits). These
7511 are useful for performing operations on data that is not in the target's
7512 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7513
7514<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7515<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7516 and low byte of the input i16 swapped. Similarly,
7517 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7518 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7519 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7520 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7521 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7522 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7523
7524</div>
7525
7526<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7527<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7528 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7529</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7530
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7531<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7532
7533<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7534<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]7535 width, or on any vector with integer elements. Not all targets support all
7536 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7537
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7538<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7539 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7540 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7541 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7542 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7543 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7544 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]7545</pre>
7546
7547<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7548<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7549 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7550
7551<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7552<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]7553 integer type, or a vector with integer elements.
7554 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7555
7556<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7557<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7558 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7559
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7560</div>
7561
7562<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7563<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7564 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7565</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7566
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7567<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7568
7569<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7570<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]7571 integer bit width, or any vector whose elements are integers. Not all
7572 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7573
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7574<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7575 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7576 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7577 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7578 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7579 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7580 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]7581</pre>
7582
7583<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7584<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7585 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7586
7587<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7588<p>The first argument is the value to be counted. This argument may be of any
7589 integer type, or a vectory with integer element type. The return type
7590 must match the first argument type.</p>
7591
7592<p>The second argument must be a constant and is a flag to indicate whether the
7593 intrinsic should ensure that a zero as the first argument produces a defined
7594 result. Historically some architectures did not provide a defined result for
7595 zero values as efficiently, and many algorithms are now predicated on
7596 avoiding zero-value inputs.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7597
7598<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7599<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7600 zeros in a variable, or within each element of the vector.
7601 If <tt>src == 0</tt> then the result is the size in bits of the type of
7602 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7603 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7604
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7605</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7606
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7607<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7608<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7609 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7610</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7611
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7612<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7613
7614<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7615<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]7616 integer bit width, or any vector of integer elements. Not all targets
7617 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7618
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7619<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7620 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7621 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7622 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7623 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7624 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7625 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]7626</pre>
7627
7628<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7629<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7630 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7631
7632<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7633<p>The first argument is the value to be counted. This argument may be of any
7634 integer type, or a vectory with integer element type. The return type
7635 must match the first argument type.</p>
7636
7637<p>The second argument must be a constant and is a flag to indicate whether the
7638 intrinsic should ensure that a zero as the first argument produces a defined
7639 result. Historically some architectures did not provide a defined result for
7640 zero values as efficiently, and many algorithms are now predicated on
7641 avoiding zero-value inputs.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7642
7643<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7644<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7645 zeros in a variable, or within each element of a vector.
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7646 If <tt>src == 0</tt> then the result is the size in bits of the type of
7647 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7648 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7649
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7650</div>
7651
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7652</div>
7653
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7654<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7655<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7656 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7657</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7659<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7660
7661<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7662
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7663<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7664<h4>
7665 <a name="int_sadd_overflow">
7666 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7667 </a>
7668</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7669
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7670<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7671
7672<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7673<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]7674 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7675
7676<pre>
7677 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7678 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7679 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7680</pre>
7681
7682<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7683<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7684 a signed addition of the two arguments, and indicate whether an overflow
7685 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7686
7687<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7688<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]7689 be of integer types of any bit width, but they must have the same bit
7690 width. The second element of the result structure must be of
7691 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7692 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7693
7694<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7695<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7696 a signed addition of the two variables. They return a structure &mdash; the
7697 first element of which is the signed summation, and the second element of
7698 which is a bit specifying if the signed summation resulted in an
7699 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7700
7701<h5>Examples:</h5>
7702<pre>
7703 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7704 %sum = extractvalue {i32, i1} %res, 0
7705 %obit = extractvalue {i32, i1} %res, 1
7706 br i1 %obit, label %overflow, label %normal
7707</pre>
7708
7709</div>
7710
7711<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7712<h4>
7713 <a name="int_uadd_overflow">
7714 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7715 </a>
7716</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7718<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7719
7720<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7721<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]7722 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7723
7724<pre>
7725 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7726 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7727 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7728</pre>
7729
7730<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7731<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7732 an unsigned addition of the two arguments, and indicate whether a carry
7733 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7734
7735<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7736<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]7737 be of integer types of any bit width, but they must have the same bit
7738 width. The second element of the result structure must be of
7739 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7740 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7741
7742<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7743<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7744 an unsigned addition of the two arguments. They return a structure &mdash;
7745 the first element of which is the sum, and the second element of which is a
7746 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7747
7748<h5>Examples:</h5>
7749<pre>
7750 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7751 %sum = extractvalue {i32, i1} %res, 0
7752 %obit = extractvalue {i32, i1} %res, 1
7753 br i1 %obit, label %carry, label %normal
7754</pre>
7755
7756</div>
7757
7758<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7759<h4>
7760 <a name="int_ssub_overflow">
7761 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7762 </a>
7763</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7764
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7765<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7766
7767<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7768<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]7769 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7770
7771<pre>
7772 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7773 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7774 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7775</pre>
7776
7777<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7778<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7779 a signed subtraction of the two arguments, and indicate whether an overflow
7780 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7781
7782<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7783<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]7784 be of integer types of any bit width, but they must have the same bit
7785 width. The second element of the result structure must be of
7786 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7787 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7788
7789<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7790<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7791 a signed subtraction of the two arguments. They return a structure &mdash;
7792 the first element of which is the subtraction, and the second element of
7793 which is a bit specifying if the signed subtraction resulted in an
7794 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7795
7796<h5>Examples:</h5>
7797<pre>
7798 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7799 %sum = extractvalue {i32, i1} %res, 0
7800 %obit = extractvalue {i32, i1} %res, 1
7801 br i1 %obit, label %overflow, label %normal
7802</pre>
7803
7804</div>
7805
7806<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7807<h4>
7808 <a name="int_usub_overflow">
7809 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7810 </a>
7811</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7812
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7813<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7814
7815<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7816<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]7817 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7818
7819<pre>
7820 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7821 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7822 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7823</pre>
7824
7825<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7826<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7827 an unsigned subtraction of the two arguments, and indicate whether an
7828 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7829
7830<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7831<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]7832 be of integer types of any bit width, but they must have the same bit
7833 width. The second element of the result structure must be of
7834 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7835 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7836
7837<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7838<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7839 an unsigned subtraction of the two arguments. They return a structure &mdash;
7840 the first element of which is the subtraction, and the second element of
7841 which is a bit specifying if the unsigned subtraction resulted in an
7842 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7843
7844<h5>Examples:</h5>
7845<pre>
7846 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7847 %sum = extractvalue {i32, i1} %res, 0
7848 %obit = extractvalue {i32, i1} %res, 1
7849 br i1 %obit, label %overflow, label %normal
7850</pre>
7851
7852</div>
7853
7854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7855<h4>
7856 <a name="int_smul_overflow">
7857 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7858 </a>
7859</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7860
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7861<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7862
7863<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7864<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]7865 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7866
7867<pre>
7868 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7869 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7870 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7871</pre>
7872
7873<h5>Overview:</h5>
7874
7875<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7876 a signed multiplication of the two arguments, and indicate whether an
7877 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7878
7879<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7880<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]7881 be of integer types of any bit width, but they must have the same bit
7882 width. The second element of the result structure must be of
7883 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7884 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7885
7886<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7887<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7888 a signed multiplication of the two arguments. They return a structure &mdash;
7889 the first element of which is the multiplication, and the second element of
7890 which is a bit specifying if the signed multiplication resulted in an
7891 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7892
7893<h5>Examples:</h5>
7894<pre>
7895 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7896 %sum = extractvalue {i32, i1} %res, 0
7897 %obit = extractvalue {i32, i1} %res, 1
7898 br i1 %obit, label %overflow, label %normal
7899</pre>
7900
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7901</div>
7902
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7903<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7904<h4>
7905 <a name="int_umul_overflow">
7906 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7907 </a>
7908</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7909
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7910<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7911
7912<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7913<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]7914 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7915
7916<pre>
7917 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7918 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7919 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7920</pre>
7921
7922<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7923<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7924 a unsigned multiplication of the two arguments, and indicate whether an
7925 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7926
7927<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7928<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]7929 be of integer types of any bit width, but they must have the same bit
7930 width. The second element of the result structure must be of
7931 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7932 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7933
7934<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7935<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7936 an unsigned multiplication of the two arguments. They return a structure
7937 &mdash; the first element of which is the multiplication, and the second
7938 element of which is a bit specifying if the unsigned multiplication resulted
7939 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7940
7941<h5>Examples:</h5>
7942<pre>
7943 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7944 %sum = extractvalue {i32, i1} %res, 0
7945 %obit = extractvalue {i32, i1} %res, 1
7946 br i1 %obit, label %overflow, label %normal
7947</pre>
7948
7949</div>
7950
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7951</div>
7952
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7953<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7954<h3>
Lang Hamesa59100c2012-06-05 19:07:46 +0000[diff] [blame]7955 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
7956</h3>
7957
7958<!-- _______________________________________________________________________ -->
7959
7960<h4>
7961 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
7962</h4>
7963
7964<div>
7965
7966<h5>Syntax:</h5>
7967<pre>
7968 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
7969 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
7970</pre>
7971
7972<h5>Overview:</h5>
7973<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
7974expressions that can be fused if the code generator determines that the fused
7975expression would be legal and efficient.</p>
7976
7977<h5>Arguments:</h5>
7978<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
7979multiplicands, a and b, and an addend c.</p>
7980
7981<h5>Semantics:</h5>
7982<p>The expression:</p>
7983<pre>
7984 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
7985</pre>
7986<p>is equivalent to the expression a * b + c, except that rounding will not be
7987performed between the multiplication and addition steps if the code generator
7988fuses the operations. Fusion is not guaranteed, even if the target platform
7989supports it. If a fused multiply-add is required the corresponding llvm.fma.*
7990intrinsic function should be used instead.</p>
7991
7992<h5>Examples:</h5>
7993<pre>
7994 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
7995</pre>
7996
7997</div>
7998
7999<!-- ======================================================================= -->
8000<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8001 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8002</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8003
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8004<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8005
Tobias Grosser6b31d172012-05-24 15:59:06 +0000[diff] [blame]8006<p>For most target platforms, half precision floating point is a storage-only
8007 format. This means that it is
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8008 a dense encoding (in memory) but does not support computation in the
8009 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8010
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8011<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8012 value as an i16, then convert it to float with <a
8013 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8014 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8015 double etc). To store the value back to memory, it is first converted to
8016 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8017 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8018 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8019
8020<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8021<h4>
8022 <a name="int_convert_to_fp16">
8023 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8024 </a>
8025</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8026
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8027<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8028
8029<h5>Syntax:</h5>
8030<pre>
8031 declare i16 @llvm.convert.to.fp16(f32 %a)
8032</pre>
8033
8034<h5>Overview:</h5>
8035<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8036 a conversion from single precision floating point format to half precision
8037 floating point format.</p>
8038
8039<h5>Arguments:</h5>
8040<p>The intrinsic function contains single argument - the value to be
8041 converted.</p>
8042
8043<h5>Semantics:</h5>
8044<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8045 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8046 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8047 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8048
8049<h5>Examples:</h5>
8050<pre>
8051 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8052 store i16 %res, i16* @x, align 2
8053</pre>
8054
8055</div>
8056
8057<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8058<h4>
8059 <a name="int_convert_from_fp16">
8060 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8061 </a>
8062</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8063
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8064<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8065
8066<h5>Syntax:</h5>
8067<pre>
8068 declare f32 @llvm.convert.from.fp16(i16 %a)
8069</pre>
8070
8071<h5>Overview:</h5>
8072<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8073 a conversion from half precision floating point format to single precision
8074 floating point format.</p>
8075
8076<h5>Arguments:</h5>
8077<p>The intrinsic function contains single argument - the value to be
8078 converted.</p>
8079
8080<h5>Semantics:</h5>
8081<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]8082 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]8083 precision floating point format. The input half-float value is represented by
8084 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8085
8086<h5>Examples:</h5>
8087<pre>
8088 %a = load i16* @x, align 2
8089 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8090</pre>
8091
8092</div>
8093
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8094</div>
8095
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]8096<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8097<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8098 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8099</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8100
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8101<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8102
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8103<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8104 prefix), are described in
8105 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8106 Level Debugging</a> document.</p>
8107
8108</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]8109
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8110<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8111<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8112 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8113</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8114
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8115<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8116
8117<p>The LLVM exception handling intrinsics (which all start with
8118 <tt>llvm.eh.</tt> prefix), are described in
8119 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8120 Handling</a> document.</p>
8121
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8122</div>
8123
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8124<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8125<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8126 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8127</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8130
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8131<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]8132 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8133 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8134 function pointer lacking the nest parameter - the caller does not need to
8135 provide a value for it. Instead, the value to use is stored in advance in a
8136 "trampoline", a block of memory usually allocated on the stack, which also
8137 contains code to splice the nest value into the argument list. This is used
8138 to implement the GCC nested function address extension.</p>
8139
8140<p>For example, if the function is
8141 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8142 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8143 follows:</p>
8144
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]8145<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8146 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8147 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8148 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8149 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]8150 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8151</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8152
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8153<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8154 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8155
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8156<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8157<h4>
8158 <a name="int_it">
8159 '<tt>llvm.init.trampoline</tt>' Intrinsic
8160 </a>
8161</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8162
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8163<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8164
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8165<h5>Syntax:</h5>
8166<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8167 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]8168</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8169
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8170<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8171<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8172 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8173
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8174<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8175<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8176 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8177 sufficiently aligned block of memory; this memory is written to by the
8178 intrinsic. Note that the size and the alignment are target-specific - LLVM
8179 currently provides no portable way of determining them, so a front-end that
8180 generates this intrinsic needs to have some target-specific knowledge.
8181 The <tt>func</tt> argument must hold a function bitcast to
8182 an <tt>i8*</tt>.</p>
8183
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8184<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8185<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]8186 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8187 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8188 which can be <a href="#int_trampoline">bitcast (to a new function) and
8189 called</a>. The new function's signature is the same as that of
8190 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8191 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8192 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8193 with the same argument list, but with <tt>nval</tt> used for the missing
8194 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8195 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8196 to the returned function pointer is undefined.</p>
8197</div>
8198
8199<!-- _______________________________________________________________________ -->
8200<h4>
8201 <a name="int_at">
8202 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8203 </a>
8204</h4>
8205
8206<div>
8207
8208<h5>Syntax:</h5>
8209<pre>
8210 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8211</pre>
8212
8213<h5>Overview:</h5>
8214<p>This performs any required machine-specific adjustment to the address of a
8215 trampoline (passed as <tt>tramp</tt>).</p>
8216
8217<h5>Arguments:</h5>
8218<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8219 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8220 </a>.</p>
8221
8222<h5>Semantics:</h5>
8223<p>On some architectures the address of the code to be executed needs to be
8224 different to the address where the trampoline is actually stored. This
8225 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8226 after performing the required machine specific adjustments.
8227 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8228 executed</a>.
8229</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8230
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8231</div>
8232
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8233</div>
8234
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8235<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8236<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8237 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8238</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8239
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8240<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8241
8242<p>This class of intrinsics exists to information about the lifetime of memory
8243 objects and ranges where variables are immutable.</p>
8244
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8245<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8246<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8247 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8248</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8249
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8250<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8251
8252<h5>Syntax:</h5>
8253<pre>
8254 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8255</pre>
8256
8257<h5>Overview:</h5>
8258<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8259 object's lifetime.</p>
8260
8261<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8262<p>The first argument is a constant integer representing the size of the
8263 object, or -1 if it is variable sized. The second argument is a pointer to
8264 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8265
8266<h5>Semantics:</h5>
8267<p>This intrinsic indicates that before this point in the code, the value of the
8268 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]8269 never be used and has an undefined value. A load from the pointer that
8270 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8271 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8272
8273</div>
8274
8275<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8276<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8277 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8278</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8279
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8280<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8281
8282<h5>Syntax:</h5>
8283<pre>
8284 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8285</pre>
8286
8287<h5>Overview:</h5>
8288<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8289 object's lifetime.</p>
8290
8291<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8292<p>The first argument is a constant integer representing the size of the
8293 object, or -1 if it is variable sized. The second argument is a pointer to
8294 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8295
8296<h5>Semantics:</h5>
8297<p>This intrinsic indicates that after this point in the code, the value of the
8298 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8299 never be used and has an undefined value. Any stores into the memory object
8300 following this intrinsic may be removed as dead.
8301
8302</div>
8303
8304<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8305<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8306 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8307</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8308
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8309<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8310
8311<h5>Syntax:</h5>
8312<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8313 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8314</pre>
8315
8316<h5>Overview:</h5>
8317<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8318 a memory object will not change.</p>
8319
8320<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8321<p>The first argument is a constant integer representing the size of the
8322 object, or -1 if it is variable sized. The second argument is a pointer to
8323 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8324
8325<h5>Semantics:</h5>
8326<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8327 the return value, the referenced memory location is constant and
8328 unchanging.</p>
8329
8330</div>
8331
8332<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8333<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8334 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8335</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8336
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8337<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8338
8339<h5>Syntax:</h5>
8340<pre>
8341 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8342</pre>
8343
8344<h5>Overview:</h5>
8345<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8346 a memory object are mutable.</p>
8347
8348<h5>Arguments:</h5>
8349<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8350 The second argument is a constant integer representing the size of the
8351 object, or -1 if it is variable sized and the third argument is a pointer
8352 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8353
8354<h5>Semantics:</h5>
8355<p>This intrinsic indicates that the memory is mutable again.</p>
8356
8357</div>
8358
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8359</div>
8360
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8361<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8362<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8363 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8364</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8365
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8366<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8367
8368<p>This class of intrinsics is designed to be generic and has no specific
8369 purpose.</p>
8370
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8371<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8372<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8373 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8374</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8376<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8377
8378<h5>Syntax:</h5>
8379<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8380 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]8381</pre>
8382
8383<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8384<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8385
8386<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8387<p>The first argument is a pointer to a value, the second is a pointer to a
8388 global string, the third is a pointer to a global string which is the source
8389 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8390
8391<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8392<p>This intrinsic allows annotation of local variables with arbitrary strings.
8393 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8394 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8395 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8396
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8397</div>
8398
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8399<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8400<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8401 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8402</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8404<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8405
8406<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8407<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8408 any integer bit width.</p>
8409
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8410<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8411 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8412 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8413 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8414 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8415 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]8416</pre>
8417
8418<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8419<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8420
8421<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8422<p>The first argument is an integer value (result of some expression), the
8423 second is a pointer to a global string, the third is a pointer to a global
8424 string which is the source file name, and the last argument is the line
8425 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8426
8427<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8428<p>This intrinsic allows annotations to be put on arbitrary expressions with
8429 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8430 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8431 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8432
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8433</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8434
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8435<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8436<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8437 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8438</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8439
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8440<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8441
8442<h5>Syntax:</h5>
8443<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8444 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8445</pre>
8446
8447<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8448<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8449
8450<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8451<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8452
8453<h5>Semantics:</h5>
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8454<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8455 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell4e711922012-05-16 00:26:51 +0000[diff] [blame]8456 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8457
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8458</div>
8459
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8460<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8461<h4>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8462 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8463</h4>
8464
8465<div>
8466
8467<h5>Syntax:</h5>
8468<pre>
Chris Lattnerff9e08b2012-05-27 23:20:41 +0000[diff] [blame]8469 declare void @llvm.debugtrap() nounwind
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8470</pre>
8471
8472<h5>Overview:</h5>
Dan Gohman164fe182012-05-14 18:58:10 +0000[diff] [blame]8473<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmandfab4432012-05-11 00:19:32 +0000[diff] [blame]8474
8475<h5>Arguments:</h5>
8476<p>None.</p>
8477
8478<h5>Semantics:</h5>
8479<p>This intrinsic is lowered to code which is intended to cause an execution
8480 trap with the intention of requesting the attention of a debugger.</p>
8481
8482</div>
8483
8484<!-- _______________________________________________________________________ -->
8485<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8486 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8487</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8488
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8489<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8490
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8491<h5>Syntax:</h5>
8492<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8493 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8494</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8495
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8496<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8497<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8498 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8499 ensure that it is placed on the stack before local variables.</p>
8500
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8501<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8502<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8503 arguments. The first argument is the value loaded from the stack
8504 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8505 that has enough space to hold the value of the guard.</p>
8506
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8507<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8508<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8509 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8510 stack. This is to ensure that if a local variable on the stack is
8511 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8512 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8513 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8514 function.</p>
8515
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8516</div>
8517
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8518<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8519<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8520 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8521</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8522
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8523<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8524
8525<h5>Syntax:</h5>
8526<pre>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8527 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8528 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8529</pre>
8530
8531<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8532<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8533 the optimizers to determine at compile time whether a) an operation (like
8534 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8535 runtime check for overflow isn't necessary. An object in this context means
8536 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8537
8538<h5>Arguments:</h5>
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8539<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8540 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8541 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8542 true) or -1 (if false) when the object size is unknown.
8543 The second argument only accepts constants.</p>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8544
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8545<h5>Semantics:</h5>
Nuno Lopes01547b32012-05-09 15:52:43 +0000[diff] [blame]8546<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8547 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopesad40c0a2012-05-22 15:25:31 +0000[diff] [blame]8548 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8549 (depending on the <tt>min</tt> argument).</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8550
8551</div>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8552<!-- _______________________________________________________________________ -->
8553<h4>
8554 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8555</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8556
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8557<div>
8558
8559<h5>Syntax:</h5>
8560<pre>
8561 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8562 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8563</pre>
8564
8565<h5>Overview:</h5>
8566<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8567 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8568
8569<h5>Arguments:</h5>
8570<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8571 argument is a value. The second argument is an expected value, this needs to
8572 be a constant value, variables are not allowed.</p>
8573
8574<h5>Semantics:</h5>
8575<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8576</div>
8577
8578</div>
8579
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8580</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8581<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8582<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8583<address>
8584 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8585 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8586 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8587 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8588
8589 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8590 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8591 Last modified: $Date$
8592</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8593
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8594</body>
8595</html>