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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ce718ff9f42c7da092eaa01dd0242e8d5ba84713 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Daniel Dunbaradea4972012-04-19 20:20:34 +0000[diff] [blame]10 <link rel="stylesheet" href="_static/llvm.css" type="text/css">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 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 Lattnerfa730212004-12-09 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 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 Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 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 Wendling987e7eb2009-07-20 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 Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 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 Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 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 Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 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 Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]106 <li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]107 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]108 </ol>
109 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]110 </ol>
111 </li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]112 <li><a href="#module_flags">Module Flags Metadata</a>
113 <ol>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]114 <li><a href="#objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a></li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]115 </ol>
116 </li>
Chris Lattner857755c2009-07-20 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 Lattner401e10c2009-07-20 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 Lattner857755c2009-07-20 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 Lattner00950542001-06-06 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 Lattner261efe92003-11-25 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]135 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]136 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]137 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]138 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 </ol>
140 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 <li><a href="#binaryops">Binary Operations</a>
142 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]148 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 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 Spencer0a783f72006-11-02 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]157 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
158 <ol>
Reid Spencer8e11bf82007-02-02 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]163 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]164 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner3df241e2006-04-08 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]172 </ol>
173 </li>
Dan Gohmana334d5f2008-05-12 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 Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]180 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]181 <ol>
Eli Friedmanff030482011-07-28 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 Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]188 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 </ol>
190 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]191 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 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 Spencerd4448792006-11-09 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 Spencer72679252006-11-11 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]204 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]205 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]206 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]207 <li><a href="#otherops">Other Operations</a>
208 <ol>
Reid Spencerf3a70a62006-11-18 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]212 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]214 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]215 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]218 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]220 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]221 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227 </ol>
228 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
230 <ol>
Reid Spencera3e435f2007-04-04 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]236 <li><a href="#int_codegen">Code Generator Intrinsics</a>
237 <ol>
Reid Spencera3e435f2007-04-04 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 Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]244 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]245 </ol>
246 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]247 <li><a href="#int_libc">Standard C Library Intrinsics</a>
248 <ol>
Reid Spencera3e435f2007-04-04 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 Gohman91c284c2007-10-15 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 Gohman08b280b2011-05-27 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 Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]259 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]260 </ol>
261 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]262 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]264 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]268 </ol>
269 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]270 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
271 <ol>
Bill Wendlingda01af72009-02-08 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]277 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]278 </ol>
279 </li>
Lang Hames5afba6f2012-06-05 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]285 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
286 <ol>
Chris Lattner82c3dc62010-03-14 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]289 </ol>
290 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]291 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]292 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]293 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]294 <ol>
295 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]296 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]297 </ol>
298 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]299 <li><a href="#int_memorymarkers">Memory Use Markers</a>
300 <ol>
Jakub Staszak8e1b12a2011-12-04 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 Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]305 </ol>
306 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]307 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]308 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]309 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]310 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]312 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]313 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]314 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]315 <li><a href="#int_debugtrap">
316 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]317 <li><a href="#int_stackprotector">
318 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]319 <li><a href="#int_objectsize">
320 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]321 <li><a href="#int_expect">
322 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]323 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]324 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]325 </ol>
326 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]327</ol>
Chris Lattnerd7923912004-05-23 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]338<div>
Bill Wendlinge910b4c2009-07-20 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]346</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]347
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]348<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]349<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]350<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]352<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]370 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]371 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]373<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]374<h4>
375 <a name="wellformed">Well-Formedness</a>
376</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]378<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]379
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]384
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]385<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]386%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387</pre>
388
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]396</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]397
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]398</div>
399
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]400<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]403<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]404<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]405
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]406<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]407
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]414<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]415 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]424 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]427 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]428 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]429</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]431<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]437<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
447<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]448 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]450<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]456<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]458<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]459%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
461
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]462<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]464<pre class="doc_code">
Gabor Greifec58f752009-10-28 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]467%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468</pre>
469
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]473<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]475 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]476
477 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]478 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]479
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]480 <li>Unnamed temporaries are numbered sequentially</li>
481</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]482
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]483<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]487
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]488</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]489
490<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]491<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]492<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]493<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]494<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]495<h3>
496 <a name="modulestructure">Module Structure</a>
497</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]499<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling4cc2be62012-03-14 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]508<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]509<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]511
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]512<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling4cc2be62012-03-14 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]514
515<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]516define i32 @main() { <i>; i32()* </i>&nbsp;
517 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]518 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.str, i64 0, i64 0
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]519
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]520 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]521 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]522 <a href="#i_ret">ret</a> i32 0&nbsp;
523}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]524
525<i>; Named metadata</i>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]526!1 = metadata !{i32 42}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]527!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]528</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530<p>This example is made up of a <a href="#globalvars">global variable</a> named
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]531 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]532 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]533 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]534 "<tt>foo</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]535
Bill Wendling4cc2be62012-03-14 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 Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]542</div>
543
544<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]545<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]546 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]547</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]548
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]549<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]551<p>All Global Variables and Functions have one of the following types of
552 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]553
554<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]555 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 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 Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]562
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]574
Bill Wendling55ae5152010-08-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]585 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]588
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]590 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 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 Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]599 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]611
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]612 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]624 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]625 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]626 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
627 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]628
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]629
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]631 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]636
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]641
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 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 Wendling5e721d72010-07-01 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 Wendlinge910b4c2009-07-20 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 Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]651
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]652 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]653 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 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 Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]656</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]661
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]662<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]663 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]664 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]669
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]670 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]671 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]676</dl>
677
Bill Wendlinge910b4c2009-07-20 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 Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]685 other than <tt>external</tt>, <tt>dllimport</tt>
686 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]688<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]689 or <tt>weak_odr</tt> linkages.</p>
690
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]691</div>
692
693<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]694<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]696</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]698<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]706
707<dl>
708 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]709 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]714
715 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]716 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 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 Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]720 (Application Binary Interface).
721 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]725
726 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]727 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]733
Chris Lattner29689432010-03-11 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 Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]754 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]755 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]756 target-specific calling conventions to be used. Target specific calling
757 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]758</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]759
760<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]761 support Pascal conventions or any other well-known target-independent
762 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]763
764</div>
765
766<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]767<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]769</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]771<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]772
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]773<p>All Global Variables and Functions have one of the following visibility
774 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]775
776<dl>
777 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]778 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]783
784 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]785 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]790
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]791 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]792 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]796</dl>
797
798</div>
799
800<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]801<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]802 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]803</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]805<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]806
807<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]811<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]812%mytype = type { %mytype*, i32 }
813</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]816 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]817 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]818
819<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]828
829</div>
830
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]831<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]832<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]833 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]834</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]835
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]836<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]837
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]838<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 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
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame^]841 alignment specified.</p>
842
843<p>A variable may be defined as <tt>thread_local</tt>, which
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]844 means that it will not be shared by threads (each thread will have a
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame^]845 separated copy of the variable). Not all targets support thread-local
846 variables. Optionally, a TLS model may be specified:</p>
847
848<dl>
849 <dt><b><tt>localdynamic</tt></b>:</dt>
850 <dd>For variables that are only used within the current shared library.</dd>
851
852 <dt><b><tt>initialexec</tt></b>:</dt>
853 <dd>For variables in modules that will not be loaded dynamically.</dd>
854
855 <dt><b><tt>localexec</tt></b>:</dt>
856 <dd>For variables defined in the executable and only used within it.</dd>
857</dl>
858
859<p>The models correspond to the ELF TLS models; see
860 <a href="http://people.redhat.com/drepper/tls.pdf">ELF
861 Handling For Thread-Local Storage</a> for more information on under which
862 circumstances the different models may be used. The target may choose a
863 different TLS model if the specified model is not supported, or if a better
864 choice of model can be made.</p>
865
866<p>A variable may be defined as a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]867 "constant," which indicates that the contents of the variable
868 will <b>never</b> be modified (enabling better optimization, allowing the
869 global data to be placed in the read-only section of an executable, etc).
870 Note that variables that need runtime initialization cannot be marked
871 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]872
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]873<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
874 constant, even if the final definition of the global is not. This capability
875 can be used to enable slightly better optimization of the program, but
876 requires the language definition to guarantee that optimizations based on the
877 'constantness' are valid for the translation units that do not include the
878 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]880<p>As SSA values, global variables define pointer values that are in scope
881 (i.e. they dominate) all basic blocks in the program. Global variables
882 always define a pointer to their "content" type because they describe a
883 region of memory, and all memory objects in LLVM are accessed through
884 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]886<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
887 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]888 like this can be merged with other constants if they have the same
889 initializer. Note that a constant with significant address <em>can</em>
890 be merged with a <tt>unnamed_addr</tt> constant, the result being a
891 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]892
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893<p>A global variable may be declared to reside in a target-specific numbered
894 address space. For targets that support them, address spaces may affect how
895 optimizations are performed and/or what target instructions are used to
896 access the variable. The default address space is zero. The address space
897 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]898
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]899<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]900 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]901
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]902<p>An explicit alignment may be specified for a global, which must be a power
903 of 2. If not present, or if the alignment is set to zero, the alignment of
904 the global is set by the target to whatever it feels convenient. If an
905 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]906 alignment. Targets and optimizers are not allowed to over-align the global
907 if the global has an assigned section. In this case, the extra alignment
908 could be observable: for example, code could assume that the globals are
909 densely packed in their section and try to iterate over them as an array,
910 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]911
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]912<p>For example, the following defines a global in a numbered address space with
913 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]914
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]915<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]916@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]917</pre>
918
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame^]919<p>The following example defines a thread-local global with
920 the <tt>initialexec</tt> TLS model:</p>
921
922<pre class="doc_code">
923@G = thread_local(initialexec) global i32 0, align 4
924</pre>
925
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926</div>
927
928
929<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]930<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]931 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]932</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]934<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]935
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]936<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]937 optional <a href="#linkage">linkage type</a>, an optional
938 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]939 <a href="#callingconv">calling convention</a>,
940 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 <a href="#paramattrs">parameter attribute</a> for the return type, a function
942 name, a (possibly empty) argument list (each with optional
943 <a href="#paramattrs">parameter attributes</a>), optional
944 <a href="#fnattrs">function attributes</a>, an optional section, an optional
945 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
946 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
949 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]950 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]951 <a href="#callingconv">calling convention</a>,
952 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]953 <a href="#paramattrs">parameter attribute</a> for the return type, a function
954 name, a possibly empty list of arguments, an optional alignment, and an
955 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]956
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]957<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]958 (Control Flow Graph) for the function. Each basic block may optionally start
959 with a label (giving the basic block a symbol table entry), contains a list
960 of instructions, and ends with a <a href="#terminators">terminator</a>
961 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]962
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]963<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]964 executed on entrance to the function, and it is not allowed to have
965 predecessor basic blocks (i.e. there can not be any branches to the entry
966 block of a function). Because the block can have no predecessors, it also
967 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]968
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]969<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]970 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]971
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]972<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]973 the alignment is set to zero, the alignment of the function is set by the
974 target to whatever it feels convenient. If an explicit alignment is
975 specified, the function is forced to have at least that much alignment. All
976 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]977
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]978<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]979 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]980
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]981<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]982<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]983define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]984 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
985 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
986 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
987 [<a href="#gc">gc</a>] { ... }
988</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]989
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]990</div>
991
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]992<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]993<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]994 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]995</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]997<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]998
999<p>Aliases act as "second name" for the aliasee value (which can be either
1000 function, global variable, another alias or bitcast of global value). Aliases
1001 may have an optional <a href="#linkage">linkage type</a>, and an
1002 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1003
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1004<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1005<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]1006@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1007</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1008
1009</div>
1010
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1011<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1012<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1013 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1014</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1015
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1016<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1017
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1018<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1019 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1020 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1021
1022<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1023<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1024; Some unnamed metadata nodes, which are referenced by the named metadata.
1025!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1026!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1027!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]1028; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1029!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1030</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1031
1032</div>
1033
1034<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1035<h3>
1036 <a name="paramattrs">Parameter Attributes</a>
1037</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1038
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1039<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1040
1041<p>The return type and each parameter of a function type may have a set of
1042 <i>parameter attributes</i> associated with them. Parameter attributes are
1043 used to communicate additional information about the result or parameters of
1044 a function. Parameter attributes are considered to be part of the function,
1045 not of the function type, so functions with different parameter attributes
1046 can have the same function type.</p>
1047
1048<p>Parameter attributes are simple keywords that follow the type specified. If
1049 multiple parameter attributes are needed, they are space separated. For
1050 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1051
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1052<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1053declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1054declare i32 @atoi(i8 zeroext)
1055declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1056</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1058<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1059 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1060
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1063<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1064 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1065 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1066 should be zero-extended to the extent required by the target's ABI (which
1067 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1068 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1069
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1070 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1072 should be sign-extended to the extent required by the target's ABI (which
1073 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1074 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1075
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1076 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1077 <dd>This indicates that this parameter or return value should be treated in a
1078 special target-dependent fashion during while emitting code for a function
1079 call or return (usually, by putting it in a register as opposed to memory,
1080 though some targets use it to distinguish between two different kinds of
1081 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1082
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1083 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1084 <dd><p>This indicates that the pointer parameter should really be passed by
1085 value to the function. The attribute implies that a hidden copy of the
1086 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087 is made between the caller and the callee, so the callee is unable to
Chris Lattneref097052012-05-30 00:40:23 +0000[diff] [blame]1088 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 pointer arguments. It is generally used to pass structs and arrays by
1090 value, but is also valid on pointers to scalars. The copy is considered
1091 to belong to the caller not the callee (for example,
1092 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1093 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1094 values.</p>
1095
1096 <p>The byval attribute also supports specifying an alignment with
1097 the align attribute. It indicates the alignment of the stack slot to
1098 form and the known alignment of the pointer specified to the call site. If
1099 the alignment is not specified, then the code generator makes a
1100 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1102 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1103 <dd>This indicates that the pointer parameter specifies the address of a
1104 structure that is the return value of the function in the source program.
1105 This pointer must be guaranteed by the caller to be valid: loads and
1106 stores to the structure may be assumed by the callee to not to trap. This
1107 may only be applied to the first parameter. This is not a valid attribute
1108 for return values. </dd>
1109
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1110 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1111 <dd>This indicates that pointer values
1112 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1113 value do not alias pointer values which are not <i>based</i> on it,
1114 ignoring certain "irrelevant" dependencies.
1115 For a call to the parent function, dependencies between memory
1116 references from before or after the call and from those during the call
1117 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1118 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1119 The caller shares the responsibility with the callee for ensuring that
1120 these requirements are met.
1121 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1122 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1123<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1124 Note that this definition of <tt>noalias</tt> is intentionally
1125 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1126 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1127<br>
1128 For function return values, C99's <tt>restrict</tt> is not meaningful,
1129 while LLVM's <tt>noalias</tt> is.
1130 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1131
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1132 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This indicates that the callee does not make any copies of the pointer
1134 that outlive the callee itself. This is not a valid attribute for return
1135 values.</dd>
1136
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1137 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1138 <dd>This indicates that the pointer parameter can be excised using the
1139 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1140 attribute for return values.</dd>
1141</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1142
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1143</div>
1144
1145<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1146<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1147 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1148</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1149
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1150<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1152<p>Each function may specify a garbage collector name, which is simply a
1153 string:</p>
1154
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1155<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1156define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1157</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1158
1159<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1160 collector which will cause the compiler to alter its output in order to
1161 support the named garbage collection algorithm.</p>
1162
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1163</div>
1164
1165<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1166<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1167 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1168</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1169
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1170<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1171
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1172<p>Function attributes are set to communicate additional information about a
1173 function. Function attributes are considered to be part of the function, not
1174 of the function type, so functions with different parameter attributes can
1175 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1177<p>Function attributes are simple keywords that follow the type specified. If
1178 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1179
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1180<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1181define void @f() noinline { ... }
1182define void @f() alwaysinline { ... }
1183define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1184define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1185</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1186
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1187<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1188 <dt><tt><b>address_safety</b></tt></dt>
1189 <dd>This attribute indicates that the address safety analysis
1190 is enabled for this function. </dd>
1191
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1192 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1193 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1194 the backend should forcibly align the stack pointer. Specify the
1195 desired alignment, which must be a power of two, in parentheses.
1196
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute indicates that the inliner should attempt to inline this
1199 function into callers whenever possible, ignoring any active inlining size
1200 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1201
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1202 <dt><tt><b>nonlazybind</b></tt></dt>
1203 <dd>This attribute suppresses lazy symbol binding for the function. This
1204 may make calls to the function faster, at the cost of extra program
1205 startup time if the function is not called during program startup.</dd>
1206
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1207 <dt><tt><b>inlinehint</b></tt></dt>
1208 <dd>This attribute indicates that the source code contained a hint that inlining
1209 this function is desirable (such as the "inline" keyword in C/C++). It
1210 is just a hint; it imposes no requirements on the inliner.</dd>
1211
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1212 <dt><tt><b>naked</b></tt></dt>
1213 <dd>This attribute disables prologue / epilogue emission for the function.
1214 This can have very system-specific consequences.</dd>
1215
1216 <dt><tt><b>noimplicitfloat</b></tt></dt>
1217 <dd>This attributes disables implicit floating point instructions.</dd>
1218
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1219 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1220 <dd>This attribute indicates that the inliner should never inline this
1221 function in any situation. This attribute may not be used together with
1222 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1223
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1224 <dt><tt><b>noredzone</b></tt></dt>
1225 <dd>This attribute indicates that the code generator should not use a red
1226 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1227
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1228 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1229 <dd>This function attribute indicates that the function never returns
1230 normally. This produces undefined behavior at runtime if the function
1231 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1232
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1233 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1234 <dd>This function attribute indicates that the function never returns with an
1235 unwind or exceptional control flow. If the function does unwind, its
1236 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1237
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1238 <dt><tt><b>optsize</b></tt></dt>
1239 <dd>This attribute suggests that optimization passes and code generator passes
1240 make choices that keep the code size of this function low, and otherwise
1241 do optimizations specifically to reduce code size.</dd>
1242
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1243 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244 <dd>This attribute indicates that the function computes its result (or decides
1245 to unwind an exception) based strictly on its arguments, without
1246 dereferencing any pointer arguments or otherwise accessing any mutable
1247 state (e.g. memory, control registers, etc) visible to caller functions.
1248 It does not write through any pointer arguments
1249 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1250 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1251 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1252
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1253 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1254 <dd>This attribute indicates that the function does not write through any
1255 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1256 arguments) or otherwise modify any state (e.g. memory, control registers,
1257 etc) visible to caller functions. It may dereference pointer arguments
1258 and read state that may be set in the caller. A readonly function always
1259 returns the same value (or unwinds an exception identically) when called
1260 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1261 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1262
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1263 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1264 <dd>This attribute indicates that this function can return twice. The
1265 C <code>setjmp</code> is an example of such a function. The compiler
1266 disables some optimizations (like tail calls) in the caller of these
1267 functions.</dd>
1268
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1269 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1270 <dd>This attribute indicates that the function should emit a stack smashing
1271 protector. It is in the form of a "canary"&mdash;a random value placed on
1272 the stack before the local variables that's checked upon return from the
1273 function to see if it has been overwritten. A heuristic is used to
1274 determine if a function needs stack protectors or not.<br>
1275<br>
1276 If a function that has an <tt>ssp</tt> attribute is inlined into a
1277 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1278 function will have an <tt>ssp</tt> attribute.</dd>
1279
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1280 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1281 <dd>This attribute indicates that the function should <em>always</em> emit a
1282 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1283 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1284<br>
1285 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1286 function that doesn't have an <tt>sspreq</tt> attribute or which has
1287 an <tt>ssp</tt> attribute, then the resulting function will have
1288 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1289
1290 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1291 <dd>This attribute indicates that the ABI being targeted requires that
1292 an unwind table entry be produce for this function even if we can
1293 show that no exceptions passes by it. This is normally the case for
1294 the ELF x86-64 abi, but it can be disabled for some compilation
1295 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1296</dl>
1297
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1298</div>
1299
1300<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1301<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1302 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1303</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1304
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1305<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1306
1307<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1308 the GCC "file scope inline asm" blocks. These blocks are internally
1309 concatenated by LLVM and treated as a single unit, but may be separated in
1310 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1311
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1312<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1313module asm "inline asm code goes here"
1314module asm "more can go here"
1315</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1316
1317<p>The strings can contain any character by escaping non-printable characters.
1318 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1320
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1321<p>The inline asm code is simply printed to the machine code .s file when
1322 assembly code is generated.</p>
1323
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1324</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1327<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1328 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1329</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1331<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1334 data is to be laid out in memory. The syntax for the data layout is
1335 simply:</p>
1336
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1337<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338target datalayout = "<i>layout specification</i>"
1339</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1340
1341<p>The <i>layout specification</i> consists of a list of specifications
1342 separated by the minus sign character ('-'). Each specification starts with
1343 a letter and may include other information after the letter to define some
1344 aspect of the data layout. The specifications accepted are as follows:</p>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346<dl>
1347 <dt><tt>E</tt></dt>
1348 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1349 bits with the most significance have the lowest address location.</dd>
1350
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1351 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1352 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1353 the bits with the least significance have the lowest address
1354 location.</dd>
1355
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1356 <dt><tt>S<i>size</i></tt></dt>
1357 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1358 of stack variables is limited to the natural stack alignment to avoid
1359 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1360 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1361 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1362
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1363 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1364 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1365 <i>preferred</i> alignments. All sizes are in bits. Specifying
1366 the <i>pref</i> alignment is optional. If omitted, the
1367 preceding <tt>:</tt> should be omitted too.</dd>
1368
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1369 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1370 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1371 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1372
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1373 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1374 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1375 <i>size</i>.</dd>
1376
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1377 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1378 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1379 <i>size</i>. Only values of <i>size</i> that are supported by the target
1380 will work. 32 (float) and 64 (double) are supported on all targets;
1381 80 or 128 (different flavors of long double) are also supported on some
1382 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1383
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1384 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1385 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1386 <i>size</i>.</dd>
1387
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1388 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1389 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1390 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1391
1392 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1393 <dd>This specifies a set of native integer widths for the target CPU
1394 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1395 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1396 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1397 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1398</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1399
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1400<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1401 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1402 specifications in the <tt>datalayout</tt> keyword. The default specifications
1403 are given in this list:</p>
1404
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1405<ul>
1406 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1407 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1408 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1409 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1410 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1411 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1412 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1413 alignment of 64-bits</li>
1414 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1415 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1416 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1417 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1418 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1419 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1420</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1421
1422<p>When LLVM is determining the alignment for a given type, it uses the
1423 following rules:</p>
1424
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1425<ol>
1426 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1427 specification is used.</li>
1428
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1429 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1430 smallest integer type that is larger than the bitwidth of the sought type
1431 is used. If none of the specifications are larger than the bitwidth then
1432 the the largest integer type is used. For example, given the default
1433 specifications above, the i7 type will use the alignment of i8 (next
1434 largest) while both i65 and i256 will use the alignment of i64 (largest
1435 specified).</li>
1436
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1437 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1438 largest vector type that is smaller than the sought vector type will be
1439 used as a fall back. This happens because &lt;128 x double&gt; can be
1440 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1441</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1442
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1443<p>The function of the data layout string may not be what you expect. Notably,
1444 this is not a specification from the frontend of what alignment the code
1445 generator should use.</p>
1446
1447<p>Instead, if specified, the target data layout is required to match what the
1448 ultimate <em>code generator</em> expects. This string is used by the
1449 mid-level optimizers to
1450 improve code, and this only works if it matches what the ultimate code
1451 generator uses. If you would like to generate IR that does not embed this
1452 target-specific detail into the IR, then you don't have to specify the
1453 string. This will disable some optimizations that require precise layout
1454 information, but this also prevents those optimizations from introducing
1455 target specificity into the IR.</p>
1456
1457
1458
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1459</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1460
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1461<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1462<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1463 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1464</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1466<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1467
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1468<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1469with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1470is undefined. Pointer values are associated with address ranges
1471according to the following rules:</p>
1472
1473<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1474 <li>A pointer value is associated with the addresses associated with
1475 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1476 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1477 range of the variable's storage.</li>
1478 <li>The result value of an allocation instruction is associated with
1479 the address range of the allocated storage.</li>
1480 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1481 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1482 <li>An integer constant other than zero or a pointer value returned
1483 from a function not defined within LLVM may be associated with address
1484 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1485 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1486 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1487</ul>
1488
1489<p>A pointer value is <i>based</i> on another pointer value according
1490 to the following rules:</p>
1491
1492<ul>
1493 <li>A pointer value formed from a
1494 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1495 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1496 <li>The result value of a
1497 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1498 of the <tt>bitcast</tt>.</li>
1499 <li>A pointer value formed by an
1500 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1501 pointer values that contribute (directly or indirectly) to the
1502 computation of the pointer's value.</li>
1503 <li>The "<i>based</i> on" relationship is transitive.</li>
1504</ul>
1505
1506<p>Note that this definition of <i>"based"</i> is intentionally
1507 similar to the definition of <i>"based"</i> in C99, though it is
1508 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1509
1510<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1511<tt><a href="#i_load">load</a></tt> merely indicates the size and
1512alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1513interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1514<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1515and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1516
1517<p>Consequently, type-based alias analysis, aka TBAA, aka
1518<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1519LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1520additional information which specialized optimization passes may use
1521to implement type-based alias analysis.</p>
1522
1523</div>
1524
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1525<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1526<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1527 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1528</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1529
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1530<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1531
1532<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1533href="#i_store"><tt>store</tt></a>s, and <a
1534href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1535The optimizers must not change the number of volatile operations or change their
1536order of execution relative to other volatile operations. The optimizers
1537<i>may</i> change the order of volatile operations relative to non-volatile
1538operations. This is not Java's "volatile" and has no cross-thread
1539synchronization behavior.</p>
1540
1541</div>
1542
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1543<!-- ======================================================================= -->
1544<h3>
1545 <a name="memmodel">Memory Model for Concurrent Operations</a>
1546</h3>
1547
1548<div>
1549
1550<p>The LLVM IR does not define any way to start parallel threads of execution
1551or to register signal handlers. Nonetheless, there are platform-specific
1552ways to create them, and we define LLVM IR's behavior in their presence. This
1553model is inspired by the C++0x memory model.</p>
1554
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1555<p>For a more informal introduction to this model, see the
1556<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1557
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1558<p>We define a <i>happens-before</i> partial order as the least partial order
1559that</p>
1560<ul>
1561 <li>Is a superset of single-thread program order, and</li>
1562 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1563 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1564 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1565 creation, thread joining, etc., and by atomic instructions.
1566 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1567 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1568</ul>
1569
1570<p>Note that program order does not introduce <i>happens-before</i> edges
1571between a thread and signals executing inside that thread.</p>
1572
1573<p>Every (defined) read operation (load instructions, memcpy, atomic
1574loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1575(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1576stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1577initialized globals are considered to have a write of the initializer which is
1578atomic and happens before any other read or write of the memory in question.
1579For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1580any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1581
1582<ul>
1583 <li>If <var>write<sub>1</sub></var> happens before
1584 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1585 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1586 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1587 <li>If <var>R<sub>byte</sub></var> happens before
1588 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1589 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1590</ul>
1591
1592<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1593<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1594 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1595 is supposed to give guarantees which can support
1596 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1597 addresses which do not behave like normal memory. It does not generally
1598 provide cross-thread synchronization.)
1599 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1600 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1601 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1602 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1603 <var>R<sub>byte</sub></var> returns the value written by that
1604 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1605 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1606 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1607 values written. See the <a href="#ordering">Atomic Memory Ordering
1608 Constraints</a> section for additional constraints on how the choice
1609 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1610 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1611</ul>
1612
1613<p><var>R</var> returns the value composed of the series of bytes it read.
1614This implies that some bytes within the value may be <tt>undef</tt>
1615<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1616defines the semantics of the operation; it doesn't mean that targets will
1617emit more than one instruction to read the series of bytes.</p>
1618
1619<p>Note that in cases where none of the atomic intrinsics are used, this model
1620places only one restriction on IR transformations on top of what is required
1621for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1622otherwise be stored is not allowed in general. (Specifically, in the case
1623where another thread might write to and read from an address, introducing a
1624store can change a load that may see exactly one write into a load that may
1625see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1626
1627<!-- FIXME: This model assumes all targets where concurrency is relevant have
1628a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1629none of the backends currently in the tree fall into this category; however,
1630there might be targets which care. If there are, we want a paragraph
1631like the following:
1632
1633Targets may specify that stores narrower than a certain width are not
1634available; on such a target, for the purposes of this model, treat any
1635non-atomic write with an alignment or width less than the minimum width
1636as if it writes to the relevant surrounding bytes.
1637-->
1638
1639</div>
1640
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1641<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1642<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1643 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1644</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1645
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1646<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647
1648<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1649<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1650<a href="#i_fence"><code>fence</code></a>,
1651<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1652<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1653that determines which other atomic instructions on the same address they
1654<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1655but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1656check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1657<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1658<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1659treat these orderings somewhat differently since they don't take an address.
1660See that instruction's documentation for details.</p>
1661
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1662<p>For a simpler introduction to the ordering constraints, see the
1663<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1664
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1665<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1666<dt><code>unordered</code></dt>
1667<dd>The set of values that can be read is governed by the happens-before
1668partial order. A value cannot be read unless some operation wrote it.
1669This is intended to provide a guarantee strong enough to model Java's
1670non-volatile shared variables. This ordering cannot be specified for
1671read-modify-write operations; it is not strong enough to make them atomic
1672in any interesting way.</dd>
1673<dt><code>monotonic</code></dt>
1674<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1675total order for modifications by <code>monotonic</code> operations on each
1676address. All modification orders must be compatible with the happens-before
1677order. There is no guarantee that the modification orders can be combined to
1678a global total order for the whole program (and this often will not be
1679possible). The read in an atomic read-modify-write operation
1680(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1681<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1682reads the value in the modification order immediately before the value it
1683writes. If one atomic read happens before another atomic read of the same
1684address, the later read must see the same value or a later value in the
1685address's modification order. This disallows reordering of
1686<code>monotonic</code> (or stronger) operations on the same address. If an
1687address is written <code>monotonic</code>ally by one thread, and other threads
1688<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1689eventually see the write. This corresponds to the C++0x/C1x
1690<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1691<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1692<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1693a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1694operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1695<dt><code>release</code></dt>
1696<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1697writes a value which is subsequently read by an <code>acquire</code> operation,
1698it <i>synchronizes-with</i> that operation. (This isn't a complete
1699description; see the C++0x definition of a release sequence.) This corresponds
1700to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1701<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1702<code>acquire</code> and <code>release</code> operation on its address.
1703This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1704<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1705<dd>In addition to the guarantees of <code>acq_rel</code>
1706(<code>acquire</code> for an operation which only reads, <code>release</code>
1707for an operation which only writes), there is a global total order on all
1708sequentially-consistent operations on all addresses, which is consistent with
1709the <i>happens-before</i> partial order and with the modification orders of
1710all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1711preceding write to the same address in this global order. This corresponds
1712to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1713</dl>
1714
1715<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1716it only <i>synchronizes with</i> or participates in modification and seq_cst
1717total orderings with other operations running in the same thread (for example,
1718in signal handlers).</p>
1719
1720</div>
1721
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1722</div>
1723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1725<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1726<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1727
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1728<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1729
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1730<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1731 intermediate representation. Being typed enables a number of optimizations
1732 to be performed on the intermediate representation directly, without having
1733 to do extra analyses on the side before the transformation. A strong type
1734 system makes it easier to read the generated code and enables novel analyses
1735 and transformations that are not feasible to perform on normal three address
1736 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1739<h3>
1740 <a name="t_classifications">Type Classifications</a>
1741</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1742
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1743<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1744
1745<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1746
1747<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1748 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1750 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1751 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1752 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1753 </tr>
1754 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1755 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1756 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1757 </tr>
1758 <tr>
1759 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1760 <td><a href="#t_integer">integer</a>,
1761 <a href="#t_floating">floating point</a>,
1762 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1763 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1764 <a href="#t_struct">structure</a>,
1765 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1766 <a href="#t_label">label</a>,
1767 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1768 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1769 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1770 <tr>
1771 <td><a href="#t_primitive">primitive</a></td>
1772 <td><a href="#t_label">label</a>,
1773 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1774 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1775 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1776 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1777 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1778 </tr>
1779 <tr>
1780 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1781 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1782 <a href="#t_function">function</a>,
1783 <a href="#t_pointer">pointer</a>,
1784 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1785 <a href="#t_vector">vector</a>,
1786 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1787 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1788 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1789 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1790</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1792<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1793 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1794 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1796</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1799<h3>
1800 <a name="t_primitive">Primitive Types</a>
1801</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1803<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1804
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1805<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1806 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1807
1808<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1809<h4>
1810 <a name="t_integer">Integer Type</a>
1811</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1812
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1813<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1814
1815<h5>Overview:</h5>
1816<p>The integer type is a very simple type that simply specifies an arbitrary
1817 bit width for the integer type desired. Any bit width from 1 bit to
1818 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1819
1820<h5>Syntax:</h5>
1821<pre>
1822 iN
1823</pre>
1824
1825<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1826 value.</p>
1827
1828<h5>Examples:</h5>
1829<table class="layout">
1830 <tr class="layout">
1831 <td class="left"><tt>i1</tt></td>
1832 <td class="left">a single-bit integer.</td>
1833 </tr>
1834 <tr class="layout">
1835 <td class="left"><tt>i32</tt></td>
1836 <td class="left">a 32-bit integer.</td>
1837 </tr>
1838 <tr class="layout">
1839 <td class="left"><tt>i1942652</tt></td>
1840 <td class="left">a really big integer of over 1 million bits.</td>
1841 </tr>
1842</table>
1843
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1844</div>
1845
1846<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1847<h4>
1848 <a name="t_floating">Floating Point Types</a>
1849</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1850
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1851<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1852
1853<table>
1854 <tbody>
1855 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1856 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1858 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1859 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1860 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1861 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1862 </tbody>
1863</table>
1864
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1865</div>
1866
1867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1868<h4>
1869 <a name="t_x86mmx">X86mmx Type</a>
1870</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1871
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1872<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1873
1874<h5>Overview:</h5>
1875<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>
1876
1877<h5>Syntax:</h5>
1878<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1879 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1880</pre>
1881
1882</div>
1883
1884<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1885<h4>
1886 <a name="t_void">Void Type</a>
1887</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1889<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1890
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1891<h5>Overview:</h5>
1892<p>The void type does not represent any value and has no size.</p>
1893
1894<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1895<pre>
1896 void
1897</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1898
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1899</div>
1900
1901<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1902<h4>
1903 <a name="t_label">Label Type</a>
1904</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1905
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1906<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1907
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1908<h5>Overview:</h5>
1909<p>The label type represents code labels.</p>
1910
1911<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1912<pre>
1913 label
1914</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1915
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1916</div>
1917
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1919<h4>
1920 <a name="t_metadata">Metadata Type</a>
1921</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1922
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1923<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1924
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1925<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1926<p>The metadata type represents embedded metadata. No derived types may be
1927 created from metadata except for <a href="#t_function">function</a>
1928 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1929
1930<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1931<pre>
1932 metadata
1933</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1934
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1935</div>
1936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1937</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1938
1939<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1940<h3>
1941 <a name="t_derived">Derived Types</a>
1942</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1944<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1945
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1946<p>The real power in LLVM comes from the derived types in the system. This is
1947 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1948 useful types. Each of these types contain one or more element types which
1949 may be a primitive type, or another derived type. For example, it is
1950 possible to have a two dimensional array, using an array as the element type
1951 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1952
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1953<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1954<h4>
1955 <a name="t_aggregate">Aggregate Types</a>
1956</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1957
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1958<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1959
1960<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1961 member types. <a href="#t_array">Arrays</a> and
1962 <a href="#t_struct">structs</a> are aggregate types.
1963 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1964
1965</div>
1966
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1967<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1968<h4>
1969 <a name="t_array">Array Type</a>
1970</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1971
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1972<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1974<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1975<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976 sequentially in memory. The array type requires a size (number of elements)
1977 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1978
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1979<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1980<pre>
1981 [&lt;# elements&gt; x &lt;elementtype&gt;]
1982</pre>
1983
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1985 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1986
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1987<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1988<table class="layout">
1989 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1990 <td class="left"><tt>[40 x i32]</tt></td>
1991 <td class="left">Array of 40 32-bit integer values.</td>
1992 </tr>
1993 <tr class="layout">
1994 <td class="left"><tt>[41 x i32]</tt></td>
1995 <td class="left">Array of 41 32-bit integer values.</td>
1996 </tr>
1997 <tr class="layout">
1998 <td class="left"><tt>[4 x i8]</tt></td>
1999 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2000 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2001</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2002<p>Here are some examples of multidimensional arrays:</p>
2003<table class="layout">
2004 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2005 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
2006 <td class="left">3x4 array of 32-bit integer values.</td>
2007 </tr>
2008 <tr class="layout">
2009 <td class="left"><tt>[12 x [10 x float]]</tt></td>
2010 <td class="left">12x10 array of single precision floating point values.</td>
2011 </tr>
2012 <tr class="layout">
2013 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
2014 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2015 </tr>
2016</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2017
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]2018<p>There is no restriction on indexing beyond the end of the array implied by
2019 a static type (though there are restrictions on indexing beyond the bounds
2020 of an allocated object in some cases). This means that single-dimension
2021 'variable sized array' addressing can be implemented in LLVM with a zero
2022 length array type. An implementation of 'pascal style arrays' in LLVM could
2023 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2024
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2025</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2026
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2027<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2028<h4>
2029 <a name="t_function">Function Type</a>
2030</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2031
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2032<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2033
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035<p>The function type can be thought of as a function signature. It consists of
2036 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]2037 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]2038
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2039<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2040<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2041 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2042</pre>
2043
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2044<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2045 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2046 which indicates that the function takes a variable number of arguments.
2047 Variable argument functions can access their arguments with
2048 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2049 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2050 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2051
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2052<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2053<table class="layout">
2054 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2055 <td class="left"><tt>i32 (i32)</tt></td>
2056 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2057 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2058 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2059 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2060 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2061 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2062 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2063 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2064 </td>
2065 </tr><tr class="layout">
2066 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2067 <td class="left">A vararg function that takes at least one
2068 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2069 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2070 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2071 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2072 </tr><tr class="layout">
2073 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2074 <td class="left">A function taking an <tt>i32</tt>, returning a
2075 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2076 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2077 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2078</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2079
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2080</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2081
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2082<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2083<h4>
2084 <a name="t_struct">Structure Type</a>
2085</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2086
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2087<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2088
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2089<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2090<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2091 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2092
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2093<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2094 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2095 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2096 Structures in registers are accessed using the
2097 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2098 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2099
2100<p>Structures may optionally be "packed" structures, which indicate that the
2101 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2102 the elements. In non-packed structs, padding between field types is inserted
2103 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2104 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2105
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2106<p>Structures can either be "literal" or "identified". A literal structure is
2107 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2108 types are always defined at the top level with a name. Literal types are
2109 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2110 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2111 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2112</p>
2113
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2114<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2115<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2116 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2117 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2118</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2119
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2120<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2121<table class="layout">
2122 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2123 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2124 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2125 </tr>
2126 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2127 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2128 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2129 second element is a <a href="#t_pointer">pointer</a> to a
2130 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2131 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2132 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2133 <tr class="layout">
2134 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2135 <td class="left">A packed struct known to be 5 bytes in size.</td>
2136 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2138
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2139</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2140
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2141<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2142<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2143 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2144</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2145
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2146<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2147
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2148<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2149<p>Opaque structure types are used to represent named structure types that do
2150 not have a body specified. This corresponds (for example) to the C notion of
2151 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2152
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2153<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2154<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2155 %X = type opaque
2156 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2157</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2158
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2159<h5>Examples:</h5>
2160<table class="layout">
2161 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2162 <td class="left"><tt>opaque</tt></td>
2163 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2164 </tr>
2165</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2166
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2167</div>
2168
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2169
2170
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2171<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2172<h4>
2173 <a name="t_pointer">Pointer Type</a>
2174</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2175
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2176<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177
2178<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2179<p>The pointer type is used to specify memory locations.
2180 Pointers are commonly used to reference objects in memory.</p>
2181
2182<p>Pointer types may have an optional address space attribute defining the
2183 numbered address space where the pointed-to object resides. The default
2184 address space is number zero. The semantics of non-zero address
2185 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186
2187<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2188 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2189
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2190<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2191<pre>
2192 &lt;type&gt; *
2193</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2194
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2195<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2196<table class="layout">
2197 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2198 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2199 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2200 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2201 </tr>
2202 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2203 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2204 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2205 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2206 <tt>i32</tt>.</td>
2207 </tr>
2208 <tr class="layout">
2209 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2210 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2211 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2212 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2213</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2215</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2216
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2217<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2218<h4>
2219 <a name="t_vector">Vector Type</a>
2220</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2221
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2222<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2223
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2224<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2225<p>A vector type is a simple derived type that represents a vector of elements.
2226 Vector types are used when multiple primitive data are operated in parallel
2227 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2228 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2229 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2230
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2231<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2232<pre>
2233 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2234</pre>
2235
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2236<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2237 may be any integer or floating point type, or a pointer to these types.
2238 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2239
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2240<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2241<table class="layout">
2242 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2243 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2244 <td class="left">Vector of 4 32-bit integer values.</td>
2245 </tr>
2246 <tr class="layout">
2247 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2248 <td class="left">Vector of 8 32-bit floating-point values.</td>
2249 </tr>
2250 <tr class="layout">
2251 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2252 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2253 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2254 <tr class="layout">
2255 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2256 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2257 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2258</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2259
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2260</div>
2261
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2262</div>
2263
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2264</div>
2265
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2266<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2267<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2268<!-- *********************************************************************** -->
2269
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2270<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2271
2272<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2273 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2274
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2275<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2276<h3>
2277 <a name="simpleconstants">Simple Constants</a>
2278</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2280<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2281
2282<dl>
2283 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2284 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2285 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2286
2287 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2288 <dd>Standard integers (such as '4') are constants of
2289 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2290 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2291
2292 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2293 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2294 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2295 notation (see below). The assembler requires the exact decimal value of a
2296 floating-point constant. For example, the assembler accepts 1.25 but
2297 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2298 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2299
2300 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2301 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2302 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303</dl>
2304
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305<p>The one non-intuitive notation for constants is the hexadecimal form of
2306 floating point constants. For example, the form '<tt>double
2307 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2308 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2309 constants are required (and the only time that they are generated by the
2310 disassembler) is when a floating point constant must be emitted but it cannot
2311 be represented as a decimal floating point number in a reasonable number of
2312 digits. For example, NaN's, infinities, and other special values are
2313 represented in their IEEE hexadecimal format so that assembly and disassembly
2314 do not cause any bits to change in the constants.</p>
2315
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2316<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2317 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2318 representation for double); half and float values must, however, be exactly
2319 representable as IEE754 half and single precision, respectively.
2320 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2321 for long double, and there are three forms of long double. The 80-bit format
2322 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2323 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2324 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2325 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2326 currently supported target uses this format. Long doubles will only work if
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]2327 they match the long double format on your target. The IEEE 16-bit format
2328 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2329 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2330
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2331<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2332</div>
2333
2334<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2335<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2336<a name="aggregateconstants"></a> <!-- old anchor -->
2337<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2338</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2339
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2340<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2341
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2342<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2343 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2344
2345<dl>
2346 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2347 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2348 type definitions (a comma separated list of elements, surrounded by braces
2349 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2350 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2351 Structure constants must have <a href="#t_struct">structure type</a>, and
2352 the number and types of elements must match those specified by the
2353 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2354
2355 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2356 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2357 definitions (a comma separated list of elements, surrounded by square
2358 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2359 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2360 the number and types of elements must match those specified by the
2361 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2362
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2363 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2364 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2365 definitions (a comma separated list of elements, surrounded by
2366 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2367 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2368 have <a href="#t_vector">vector type</a>, and the number and types of
2369 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2370
2371 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2372 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2373 value to zero of <em>any</em> type, including scalar and
2374 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2375 This is often used to avoid having to print large zero initializers
2376 (e.g. for large arrays) and is always exactly equivalent to using explicit
2377 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2378
2379 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2380 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2381 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2382 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2383 be interpreted as part of the instruction stream, metadata is a place to
2384 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2385</dl>
2386
2387</div>
2388
2389<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2390<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2391 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2392</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2394<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2396<p>The addresses of <a href="#globalvars">global variables</a>
2397 and <a href="#functionstructure">functions</a> are always implicitly valid
2398 (link-time) constants. These constants are explicitly referenced when
2399 the <a href="#identifiers">identifier for the global</a> is used and always
2400 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2401 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2402
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2403<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2404@X = global i32 17
2405@Y = global i32 42
2406@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2407</pre>
2408
2409</div>
2410
2411<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2412<h3>
2413 <a name="undefvalues">Undefined Values</a>
2414</h3>
2415
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2416<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2417
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2418<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2419 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2420 Undefined values may be of any type (other than '<tt>label</tt>'
2421 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2422
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2423<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2424 program is well defined no matter what value is used. This gives the
2425 compiler more freedom to optimize. Here are some examples of (potentially
2426 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2427
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2428
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2429<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2430 %A = add %X, undef
2431 %B = sub %X, undef
2432 %C = xor %X, undef
2433Safe:
2434 %A = undef
2435 %B = undef
2436 %C = undef
2437</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2438
2439<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2440 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2441
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2442<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2443 %A = or %X, undef
2444 %B = and %X, undef
2445Safe:
2446 %A = -1
2447 %B = 0
2448Unsafe:
2449 %A = undef
2450 %B = undef
2451</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2452
2453<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2454 For example, if <tt>%X</tt> has a zero bit, then the output of the
2455 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2456 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2457 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2458 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2459 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2460 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2461 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2462
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2463<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2464 %A = select undef, %X, %Y
2465 %B = select undef, 42, %Y
2466 %C = select %X, %Y, undef
2467Safe:
2468 %A = %X (or %Y)
2469 %B = 42 (or %Y)
2470 %C = %Y
2471Unsafe:
2472 %A = undef
2473 %B = undef
2474 %C = undef
2475</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2476
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2477<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2478 branch) conditions can go <em>either way</em>, but they have to come from one
2479 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2480 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2481 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2482 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2483 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2484 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2485
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2486<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2487 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2488
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2489 %B = undef
2490 %C = xor %B, %B
2491
2492 %D = undef
2493 %E = icmp lt %D, 4
2494 %F = icmp gte %D, 4
2495
2496Safe:
2497 %A = undef
2498 %B = undef
2499 %C = undef
2500 %D = undef
2501 %E = undef
2502 %F = undef
2503</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2504
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2505<p>This example points out that two '<tt>undef</tt>' operands are not
2506 necessarily the same. This can be surprising to people (and also matches C
2507 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2508 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2509 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2510 its value over its "live range". This is true because the variable doesn't
2511 actually <em>have a live range</em>. Instead, the value is logically read
2512 from arbitrary registers that happen to be around when needed, so the value
2513 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2514 need to have the same semantics or the core LLVM "replace all uses with"
2515 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2516
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2517<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2518 %A = fdiv undef, %X
2519 %B = fdiv %X, undef
2520Safe:
2521 %A = undef
2522b: unreachable
2523</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2524
2525<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2526 value</em> and <em>undefined behavior</em>. An undefined value (like
2527 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2528 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2529 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2530 defined on SNaN's. However, in the second example, we can make a more
2531 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2532 arbitrary value, we are allowed to assume that it could be zero. Since a
2533 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2534 the operation does not execute at all. This allows us to delete the divide and
2535 all code after it. Because the undefined operation "can't happen", the
2536 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2537
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2538<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2539a: store undef -> %X
2540b: store %X -> undef
2541Safe:
2542a: &lt;deleted&gt;
2543b: unreachable
2544</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2545
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2546<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2547 undefined value can be assumed to not have any effect; we can assume that the
2548 value is overwritten with bits that happen to match what was already there.
2549 However, a store <em>to</em> an undefined location could clobber arbitrary
2550 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2551
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2552</div>
2553
2554<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2555<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2556 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2557</h3>
2558
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2559<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2560
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2561<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2562 they also represent the fact that an instruction or constant expression which
2563 cannot evoke side effects has nevertheless detected a condition which results
2564 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2565
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2566<p>There is currently no way of representing a poison value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2567 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2568 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2569
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2570<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2571
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2572<ul>
2573<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2574 their operands.</li>
2575
2576<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2577 to their dynamic predecessor basic block.</li>
2578
2579<li>Function arguments depend on the corresponding actual argument values in
2580 the dynamic callers of their functions.</li>
2581
2582<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2583 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2584 control back to them.</li>
2585
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2586<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2587 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_resume"><tt>resume</tt></a>,
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2588 or exception-throwing call instructions that dynamically transfer control
2589 back to them.</li>
2590
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2591<li>Non-volatile loads and stores depend on the most recent stores to all of the
2592 referenced memory addresses, following the order in the IR
2593 (including loads and stores implied by intrinsics such as
2594 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2595
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2596<!-- TODO: In the case of multiple threads, this only applies if the store
2597 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2598
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2599<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2600
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2601<li>An instruction with externally visible side effects depends on the most
2602 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2603 the order in the IR. (This includes
2604 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2605
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2606<li>An instruction <i>control-depends</i> on a
2607 <a href="#terminators">terminator instruction</a>
2608 if the terminator instruction has multiple successors and the instruction
2609 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2610 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2611
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2612<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2613 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2614 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2615 successor.</li>
2616
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2617<li>Dependence is transitive.</li>
2618
2619</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2620
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2621<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2622 with the additional affect that any instruction which has a <i>dependence</i>
2623 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2624
2625<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2626
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2627<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2628entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2629 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2630 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2631 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2632 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2633
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2634 store i32 %poison, i32* @g ; Poison value stored to memory.
2635 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2636
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2637 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2638
2639 %narrowaddr = bitcast i32* @g to i16*
2640 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2641 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2642 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2643
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2644 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2645 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2646
2647true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2648 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2649 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2650 br label %end
2651
2652end:
2653 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2654 ; Both edges into this PHI are
2655 ; control-dependent on %cmp, so this
2656 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2657
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2658 store volatile i32 0, i32* @g ; This would depend on the store in %true
2659 ; if %cmp is true, or the store in %entry
2660 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2661
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2662 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2663 ; The same branch again, but this time the
2664 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2665
2666second_true:
2667 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2668 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2669
2670second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2671 store volatile i32 0, i32* @g ; This time, the instruction always depends
2672 ; on the store in %end. Also, it is
2673 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2674 ; well-defined (ignoring earlier undefined
2675 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2676</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2677
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2678</div>
2679
2680<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2681<h3>
2682 <a name="blockaddress">Addresses of Basic Blocks</a>
2683</h3>
2684
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2685<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2686
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2687<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2688
2689<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2690 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2691 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2692
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2693<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2694 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2695 comparisons against null. Pointer equality tests between labels addresses
2696 results in undefined behavior &mdash; though, again, comparison against null
2697 is ok, and no label is equal to the null pointer. This may be passed around
2698 as an opaque pointer sized value as long as the bits are not inspected. This
2699 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2700 long as the original value is reconstituted before the <tt>indirectbr</tt>
2701 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2702
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2703<p>Finally, some targets may provide defined semantics when using the value as
2704 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2705
2706</div>
2707
2708
2709<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2710<h3>
2711 <a name="constantexprs">Constant Expressions</a>
2712</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2713
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2714<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2715
2716<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2717 to be used as constants. Constant expressions may be of
2718 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2719 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2720 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2721
2722<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2723 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2724 <dd>Truncate a constant to another type. The bit size of CST must be larger
2725 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2726
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2727 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2728 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2729 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2730
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2731 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2732 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2733 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2734
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2736 <dd>Truncate a floating point constant to another floating point type. The
2737 size of CST must be larger than the size of TYPE. Both types must be
2738 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2739
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2740 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2741 <dd>Floating point extend a constant to another type. The size of CST must be
2742 smaller or equal to the size of TYPE. Both types must be floating
2743 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2746 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2747 constant. TYPE must be a scalar or vector integer type. CST must be of
2748 scalar or vector floating point type. Both CST and TYPE must be scalars,
2749 or vectors of the same number of elements. If the value won't fit in the
2750 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2753 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2754 constant. TYPE must be a scalar or vector integer type. CST must be of
2755 scalar or vector floating point type. Both CST and TYPE must be scalars,
2756 or vectors of the same number of elements. If the value won't fit in the
2757 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2758
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2760 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2761 constant. TYPE must be a scalar or vector floating point type. CST must be
2762 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2763 vectors of the same number of elements. If the value won't fit in the
2764 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2765
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2766 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2767 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2768 constant. TYPE must be a scalar or vector floating point type. CST must be
2769 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2770 vectors of the same number of elements. If the value won't fit in the
2771 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2772
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2773 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2774 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2775 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2776 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2777 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2778
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2779 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2780 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2781 type. CST must be of integer type. The CST value is zero extended,
2782 truncated, or unchanged to make it fit in a pointer size. This one is
2783 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2784
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2785 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2786 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2787 are the same as those for the <a href="#i_bitcast">bitcast
2788 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2789
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2790 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2791 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2792 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2794 instruction, the index list may have zero or more indexes, which are
2795 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2796
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2797 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2799
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2800 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2801 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2802
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2803 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2804 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2805
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2806 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2807 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2808 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2809
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2810 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2812 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2813
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2814 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2816 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2817
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2818 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2819 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2820 constants. The index list is interpreted in a similar manner as indices in
2821 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2822 index value must be specified.</dd>
2823
2824 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2825 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2826 constants. The index list is interpreted in a similar manner as indices in
2827 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2828 index value must be specified.</dd>
2829
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2830 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2831 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2832 be any of the <a href="#binaryops">binary</a>
2833 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2834 on operands are the same as those for the corresponding instruction
2835 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2836</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2838</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2839
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2840</div>
2841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2843<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2844<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2845<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2846<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2847<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2848<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2849</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2850
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2851<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2852
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2854 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2855 a special value. This value represents the inline assembler as a string
2856 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2857 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2858 expression has side effects, and a flag indicating whether the function
2859 containing the asm needs to align its stack conservatively. An example
2860 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2861
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2862<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2863i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2864</pre>
2865
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2867 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2868 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2869
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2870<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2871%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2872</pre>
2873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<p>Inline asms with side effects not visible in the constraint list must be
2875 marked as having side effects. This is done through the use of the
2876 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2878<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2879call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2880</pre>
2881
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2882<p>In some cases inline asms will contain code that will not work unless the
2883 stack is aligned in some way, such as calls or SSE instructions on x86,
2884 yet will not contain code that does that alignment within the asm.
2885 The compiler should make conservative assumptions about what the asm might
2886 contain and should generate its usual stack alignment code in the prologue
2887 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2888
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2889<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2890call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2891</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2892
2893<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2894 first.</p>
2895
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2896<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2897<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898 documented here. Constraints on what can be done (e.g. duplication, moving,
2899 etc need to be documented). This is probably best done by reference to
2900 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2901 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2902
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2903<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2904<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2905 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2906</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2907
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2908<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2909
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2910<p>The call instructions that wrap inline asm nodes may have a
2911 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2912 integers. If present, the code generator will use the integer as the
2913 location cookie value when report errors through the <tt>LLVMContext</tt>
2914 error reporting mechanisms. This allows a front-end to correlate backend
2915 errors that occur with inline asm back to the source code that produced it.
2916 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2917
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2918<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2919call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2920...
2921!42 = !{ i32 1234567 }
2922</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2923
2924<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2925 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2926 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2927
2928</div>
2929
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2930</div>
2931
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2932<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2933<h3>
2934 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2935</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2937<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2938
2939<p>LLVM IR allows metadata to be attached to instructions in the program that
2940 can convey extra information about the code to the optimizers and code
2941 generator. One example application of metadata is source-level debug
2942 information. There are two metadata primitives: strings and nodes. All
2943 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2944 preceding exclamation point ('<tt>!</tt>').</p>
2945
2946<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2947 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2948 "<tt>xx</tt>" is the two digit hex code. For example:
2949 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2950
2951<p>Metadata nodes are represented with notation similar to structure constants
2952 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2953 exclamation point). Metadata nodes can have any values as their operand. For
2954 example:</p>
2955
2956<div class="doc_code">
2957<pre>
2958!{ metadata !"test\00", i32 10}
2959</pre>
2960</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2961
2962<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2963 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2964 example:</p>
2965
2966<div class="doc_code">
2967<pre>
2968!foo = metadata !{!4, !3}
2969</pre>
2970</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2971
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2972<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2973 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2974
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2975<div class="doc_code">
2976<pre>
2977call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2978</pre>
2979</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2980
2981<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2982 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2983 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2984
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2985<div class="doc_code">
2986<pre>
2987%indvar.next = add i64 %indvar, 1, !dbg !21
2988</pre>
2989</div>
2990
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2991<p>More information about specific metadata nodes recognized by the optimizers
2992 and code generator is found below.</p>
2993
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2994<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2995<h4>
2996 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2997</h4>
2998
2999<div>
3000
3001<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
3002 suitable for doing TBAA. Instead, metadata is added to the IR to describe
3003 a type system of a higher level language. This can be used to implement
3004 typical C/C++ TBAA, but it can also be used to implement custom alias
3005 analysis behavior for other languages.</p>
3006
3007<p>The current metadata format is very simple. TBAA metadata nodes have up to
3008 three fields, e.g.:</p>
3009
3010<div class="doc_code">
3011<pre>
3012!0 = metadata !{ metadata !"an example type tree" }
3013!1 = metadata !{ metadata !"int", metadata !0 }
3014!2 = metadata !{ metadata !"float", metadata !0 }
3015!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
3016</pre>
3017</div>
3018
3019<p>The first field is an identity field. It can be any value, usually
3020 a metadata string, which uniquely identifies the type. The most important
3021 name in the tree is the name of the root node. Two trees with
3022 different root node names are entirely disjoint, even if they
3023 have leaves with common names.</p>
3024
3025<p>The second field identifies the type's parent node in the tree, or
3026 is null or omitted for a root node. A type is considered to alias
3027 all of its descendants and all of its ancestors in the tree. Also,
3028 a type is considered to alias all types in other trees, so that
3029 bitcode produced from multiple front-ends is handled conservatively.</p>
3030
3031<p>If the third field is present, it's an integer which if equal to 1
3032 indicates that the type is "constant" (meaning
3033 <tt>pointsToConstantMemory</tt> should return true; see
3034 <a href="AliasAnalysis.html#OtherItfs">other useful
3035 <tt>AliasAnalysis</tt> methods</a>).</p>
3036
3037</div>
3038
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3039<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3040<h4>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3041 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3042</h4>
3043
3044<div>
3045
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3046<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3047 type. It can be used to express the maximum acceptable error in the result of
3048 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3049 more efficient but less accurate method of computing it. ULP is defined as
3050 follows:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3051
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3052<blockquote>
3053
3054<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3055 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3056 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3057 distance between the two non-equal finite floating-point numbers nearest
3058 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3059
3060</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3061
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3062<p>The metadata node shall consist of a single positive floating point number
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3063 representing the maximum relative error, for example:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3064
3065<div class="doc_code">
3066<pre>
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3067!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3068</pre>
3069</div>
3070
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000[diff] [blame]3071</div>
3072
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3073<!-- _______________________________________________________________________ -->
3074<h4>
3075 <a name="range">'<tt>range</tt>' Metadata</a>
3076</h4>
3077
3078<div>
3079<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3080 expresses the possible ranges the loaded value is in. The ranges are
3081 represented with a flattened list of integers. The loaded value is known to
3082 be in the union of the ranges defined by each consecutive pair. Each pair
3083 has the following properties:</p>
3084<ul>
3085 <li>The type must match the type loaded by the instruction.</li>
3086 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3087 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3088 <li>The range is allowed to wrap.</li>
3089 <li>The range should not represent the full or empty set. That is,
3090 <tt>a!=b</tt>. </li>
3091</ul>
Rafael Espindolaa1b95f52012-05-31 16:04:26 +0000[diff] [blame]3092<p> In addition, the pairs must be in signed order of the lower bound and
3093 they must be non-contiguous.</p>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3094
3095<p>Examples:</p>
3096<div class="doc_code">
3097<pre>
3098 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3099 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3100 %c = load i8* %z, align 1, !range !2 ; Can only be 0, 1, 3, 4 or 5
Rafael Espindolac49b29e2012-05-31 13:45:46 +0000[diff] [blame]3101 %d = load i8* %z, align 1, !range !3 ; Can only be -2, -1, 3, 4 or 5
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3102...
3103!0 = metadata !{ i8 0, i8 2 }
3104!1 = metadata !{ i8 255, i8 2 }
3105!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindolac49b29e2012-05-31 13:45:46 +0000[diff] [blame]3106!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3107</pre>
3108</div>
3109</div>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3110</div>
3111
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3112</div>
3113
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3114<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3115<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3116 <a name="module_flags">Module Flags Metadata</a>
3117</h2>
3118<!-- *********************************************************************** -->
3119
3120<div>
3121
3122<p>Information about the module as a whole is difficult to convey to LLVM's
3123 subsystems. The LLVM IR isn't sufficient to transmit this
3124 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3125 facilitate this. These flags are in the form of key / value pairs &mdash;
3126 much like a dictionary &mdash; making it easy for any subsystem who cares
3127 about a flag to look it up.</p>
3128
3129<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3130 triplets. Each triplet has the following form:</p>
3131
3132<ul>
3133 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3134 when two (or more) modules are merged together, and it encounters two (or
3135 more) metadata with the same ID. The supported behaviors are described
3136 below.</li>
3137
3138 <li>The second element is a metadata string that is a unique ID for the
3139 metadata. How each ID is interpreted is documented below.</li>
3140
3141 <li>The third element is the value of the flag.</li>
3142</ul>
3143
3144<p>When two (or more) modules are merged together, the resulting
3145 <tt>llvm.module.flags</tt> metadata is the union of the
3146 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3147 with the <i>Override</i> behavior, which may override another flag's value
3148 (see below).</p>
3149
3150<p>The following behaviors are supported:</p>
3151
3152<table border="1" cellspacing="0" cellpadding="4">
3153 <tbody>
3154 <tr>
3155 <th>Value</th>
3156 <th>Behavior</th>
3157 </tr>
3158 <tr>
3159 <td>1</td>
3160 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3161 <dl>
3162 <dt><b>Error</b></dt>
3163 <dd>Emits an error if two values disagree. It is an error to have an ID
3164 with both an Error and a Warning behavior.</dd>
3165 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3166 </td>
3167 </tr>
3168 <tr>
3169 <td>2</td>
3170 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3171 <dl>
3172 <dt><b>Warning</b></dt>
3173 <dd>Emits a warning if two values disagree.</dd>
3174 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3175 </td>
3176 </tr>
3177 <tr>
3178 <td>3</td>
3179 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3180 <dl>
3181 <dt><b>Require</b></dt>
3182 <dd>Emits an error when the specified value is not present or doesn't
3183 have the specified value. It is an error for two (or more)
3184 <tt>llvm.module.flags</tt> with the same ID to have the Require
3185 behavior but different values. There may be multiple Require flags
3186 per ID.</dd>
3187 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3188 </td>
3189 </tr>
3190 <tr>
3191 <td>4</td>
3192 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3193 <dl>
3194 <dt><b>Override</b></dt>
3195 <dd>Uses the specified value if the two values disagree. It is an
3196 error for two (or more) <tt>llvm.module.flags</tt> with the same
3197 ID to have the Override behavior but different values.</dd>
3198 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3199 </td>
3200 </tr>
3201 </tbody>
3202</table>
3203
3204<p>An example of module flags:</p>
3205
3206<pre class="doc_code">
3207!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3208!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3209!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3210!3 = metadata !{ i32 3, metadata !"qux",
3211 metadata !{
3212 metadata !"foo", i32 1
3213 }
3214}
3215!llvm.module.flags = !{ !0, !1, !2, !3 }
3216</pre>
3217
3218<ul>
3219 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3220 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3221 error if their values are not equal.</p></li>
3222
3223 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3224 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3225 value '37' if their values are not equal.</p></li>
3226
3227 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3228 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3229 warning if their values are not equal.</p></li>
3230
3231 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3232
3233<pre class="doc_code">
3234metadata !{ metadata !"foo", i32 1 }
3235</pre>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3236
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3237 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3238 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3239 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3240 the same value or an error will be issued.</p></li>
3241</ul>
3242
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3243
3244<!-- ======================================================================= -->
3245<h3>
3246<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3247</h3>
3248
3249<div>
3250
3251<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3252 in a special section called "image info". The metadata consists of a version
3253 number and a bitmask specifying what types of garbage collection are
3254 supported (if any) by the file. If two or more modules are linked together
3255 their garbage collection metadata needs to be merged rather than appended
3256 together.</p>
3257
3258<p>The Objective-C garbage collection module flags metadata consists of the
3259 following key-value pairs:</p>
3260
3261<table border="1" cellspacing="0" cellpadding="4">
Bill Wendlingb3ef2232012-03-06 09:23:25 +0000[diff] [blame]3262 <col width="30%">
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3263 <tbody>
3264 <tr>
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3265 <th>Key</th>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3266 <th>Value</th>
3267 </tr>
3268 <tr>
3269 <td><tt>Objective-C&nbsp;Version</tt></td>
3270 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3271 version. Valid values are 1 and 2.</td>
3272 </tr>
3273 <tr>
3274 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3275 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3276 section. Currently always 0.</td>
3277 </tr>
3278 <tr>
3279 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3280 <td align="left"><b>[Required]</b> &mdash; The section to place the
3281 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3282 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3283 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3284 </tr>
3285 <tr>
3286 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3287 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3288 collection is supported or not. Valid values are 0, for no garbage
3289 collection, and 2, for garbage collection supported.</td>
3290 </tr>
3291 <tr>
3292 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3293 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3294 collection is supported. If present, its value must be 6. This flag
3295 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3296 value 2.</td>
3297 </tr>
3298 </tbody>
3299</table>
3300
3301<p>Some important flag interactions:</p>
3302
3303<ul>
3304 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3305 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3306 2, then the resulting module has the <tt>Objective-C Garbage
3307 Collection</tt> flag set to 0.</li>
3308
3309 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3310 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3311</ul>
3312
3313</div>
3314
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3315</div>
3316
3317<!-- *********************************************************************** -->
3318<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3319 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3320</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3321<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3322<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3323<p>LLVM has a number of "magic" global variables that contain data that affect
3324code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3325of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3326section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3327by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3328
3329<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3330<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3331<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3332</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3333
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3334<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3335
3336<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3337href="#linkage_appending">appending linkage</a>. This array contains a list of
3338pointers to global variables and functions which may optionally have a pointer
3339cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3340
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3341<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3342<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3343@X = global i8 4
3344@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3345
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3346@llvm.used = appending global [2 x i8*] [
3347 i8* @X,
3348 i8* bitcast (i32* @Y to i8*)
3349], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3350</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3351</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3352
3353<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3354 compiler, assembler, and linker are required to treat the symbol as if there
3355 is a reference to the global that it cannot see. For example, if a variable
3356 has internal linkage and no references other than that from
3357 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3358 represent references from inline asms and other things the compiler cannot
3359 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3360
3361<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3362 object file to prevent the assembler and linker from molesting the
3363 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3364
3365</div>
3366
3367<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3368<h3>
3369 <a name="intg_compiler_used">
3370 The '<tt>llvm.compiler.used</tt>' Global Variable
3371 </a>
3372</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3373
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3374<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3375
3376<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3377 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3378 touching the symbol. On targets that support it, this allows an intelligent
3379 linker to optimize references to the symbol without being impeded as it would
3380 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3381
3382<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3383 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3384
3385</div>
3386
3387<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3388<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3389<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3390</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3392<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3393
3394<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3395<pre>
3396%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3397@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3398</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3399</div>
3400
3401<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3402 functions and associated priorities. The functions referenced by this array
3403 will be called in ascending order of priority (i.e. lowest first) when the
3404 module is loaded. The order of functions with the same priority is not
3405 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3406
3407</div>
3408
3409<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3410<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3411<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3412</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3414<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3415
3416<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3417<pre>
3418%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3419@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3420</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3421</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3422
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3423<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3424 and associated priorities. The functions referenced by this array will be
3425 called in descending order of priority (i.e. highest first) when the module
3426 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3427
3428</div>
3429
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3430</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3431
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3432<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3433<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3434<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3435
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3436<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3437
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438<p>The LLVM instruction set consists of several different classifications of
3439 instructions: <a href="#terminators">terminator
3440 instructions</a>, <a href="#binaryops">binary instructions</a>,
3441 <a href="#bitwiseops">bitwise binary instructions</a>,
3442 <a href="#memoryops">memory instructions</a>, and
3443 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3445<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3446<h3>
3447 <a name="terminators">Terminator Instructions</a>
3448</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3449
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3450<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3451
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3453 in a program ends with a "Terminator" instruction, which indicates which
3454 block should be executed after the current block is finished. These
3455 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3456 control flow, not values (the one exception being the
3457 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3458
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3459<p>The terminator instructions are:
3460 '<a href="#i_ret"><tt>ret</tt></a>',
3461 '<a href="#i_br"><tt>br</tt></a>',
3462 '<a href="#i_switch"><tt>switch</tt></a>',
3463 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3464 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3465 '<a href="#i_resume"><tt>resume</tt></a>', and
3466 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3467
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3468<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3469<h4>
3470 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3471</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3473<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3476<pre>
3477 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3478 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3479</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3481<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3483 a value) from a function back to the caller.</p>
3484
3485<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3486 value and then causes control flow, and one that just causes control flow to
3487 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3488
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3489<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3491 return value. The type of the return value must be a
3492 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3493
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3495 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3496 value or a return value with a type that does not match its type, or if it
3497 has a void return type and contains a '<tt>ret</tt>' instruction with a
3498 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3500<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3502 the calling function's context. If the caller is a
3503 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3504 instruction after the call. If the caller was an
3505 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3506 the beginning of the "normal" destination block. If the instruction returns
3507 a value, that value shall set the call or invoke instruction's return
3508 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3509
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3510<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3511<pre>
3512 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3513 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3514 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3515</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3517</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3518<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3519<h4>
3520 <a name="i_br">'<tt>br</tt>' Instruction</a>
3521</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3523<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3527 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3528 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3529</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3533 different basic block in the current function. There are two forms of this
3534 instruction, corresponding to a conditional branch and an unconditional
3535 branch.</p>
3536
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3537<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3539 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3540 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3541 target.</p>
3542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3543<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3544<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3546 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3547 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3549<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3550<pre>
3551Test:
3552 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3553 br i1 %cond, label %IfEqual, label %IfUnequal
3554IfEqual:
3555 <a href="#i_ret">ret</a> i32 1
3556IfUnequal:
3557 <a href="#i_ret">ret</a> i32 0
3558</pre>
3559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3562<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3563<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3564 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3565</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3566
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3567<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3568
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3569<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3570<pre>
3571 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3572</pre>
3573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3574<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3575<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576 several different places. It is a generalization of the '<tt>br</tt>'
3577 instruction, allowing a branch to occur to one of many possible
3578 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3580<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3581<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3582 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3583 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3584 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3587<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3589 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3590 transferred to the corresponding destination; otherwise, control flow is
3591 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3592
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3593<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3594<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3595 <tt>switch</tt> instruction, this instruction may be code generated in
3596 different ways. For example, it could be generated as a series of chained
3597 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3598
3599<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3600<pre>
3601 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3602 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3603 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3604
3605 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3606 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3607
3608 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3609 switch i32 %val, label %otherwise [ i32 0, label %onzero
3610 i32 1, label %onone
3611 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3612</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3614</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3615
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3616
3617<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3618<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3619 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3620</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3621
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3622<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3623
3624<h5>Syntax:</h5>
3625<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3626 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3627</pre>
3628
3629<h5>Overview:</h5>
3630
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3631<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3632 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3633 "<tt>address</tt>". Address must be derived from a <a
3634 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3635
3636<h5>Arguments:</h5>
3637
3638<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3639 rest of the arguments indicate the full set of possible destinations that the
3640 address may point to. Blocks are allowed to occur multiple times in the
3641 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3642
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3643<p>This destination list is required so that dataflow analysis has an accurate
3644 understanding of the CFG.</p>
3645
3646<h5>Semantics:</h5>
3647
3648<p>Control transfers to the block specified in the address argument. All
3649 possible destination blocks must be listed in the label list, otherwise this
3650 instruction has undefined behavior. This implies that jumps to labels
3651 defined in other functions have undefined behavior as well.</p>
3652
3653<h5>Implementation:</h5>
3654
3655<p>This is typically implemented with a jump through a register.</p>
3656
3657<h5>Example:</h5>
3658<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3659 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3660</pre>
3661
3662</div>
3663
3664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3665<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3666<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3667 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3668</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3669
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3670<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3671
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3672<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3673<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3674 &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 Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]3675 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3676</pre>
3677
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3678<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3679<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3680 function, with the possibility of control flow transfer to either the
3681 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3682 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3683 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3684 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3685 instruction or other exception handling mechanism, control is interrupted and
3686 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3687
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3688<p>The '<tt>exception</tt>' label is a
3689 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3690 exception. As such, '<tt>exception</tt>' label is required to have the
3691 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3692 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3693 happens, as its first non-PHI instruction. The restrictions on the
3694 "<tt>landingpad</tt>" instruction's tightly couples it to the
3695 "<tt>invoke</tt>" instruction, so that the important information contained
3696 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3697 code motion.</p>
3698
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3699<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3700<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3702<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3704 convention</a> the call should use. If none is specified, the call
3705 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3706
3707 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3708 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3709 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3710
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3711 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712 function value being invoked. In most cases, this is a direct function
3713 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3714 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3715
3716 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3717 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3718
3719 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3720 signature argument types and parameter attributes. All arguments must be
3721 of <a href="#t_firstclass">first class</a> type. If the function
3722 signature indicates the function accepts a variable number of arguments,
3723 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3724
3725 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3727
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3728 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3729 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3730 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3731
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3732 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3734 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3735</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3736
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3737<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738<p>This instruction is designed to operate as a standard
3739 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3740 primary difference is that it establishes an association with a label, which
3741 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3742
3743<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3745 exception. Additionally, this is important for implementation of
3746 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3747
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748<p>For the purposes of the SSA form, the definition of the value returned by the
3749 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3750 block to the "normal" label. If the callee unwinds then no return value is
3751 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3753<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3754<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3755 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3756 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3757 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3758 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3759</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3760
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3762
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3763 <!-- _______________________________________________________________________ -->
3764
3765<h4>
3766 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3767</h4>
3768
3769<div>
3770
3771<h5>Syntax:</h5>
3772<pre>
3773 resume &lt;type&gt; &lt;value&gt;
3774</pre>
3775
3776<h5>Overview:</h5>
3777<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3778 successors.</p>
3779
3780<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3781<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3782 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3783 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
3786<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3787 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3788 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3789
3790<h5>Example:</h5>
3791<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3792 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3793</pre>
3794
3795</div>
3796
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3797<!-- _______________________________________________________________________ -->
3798
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3799<h4>
3800 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3801</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3803<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3804
3805<h5>Syntax:</h5>
3806<pre>
3807 unreachable
3808</pre>
3809
3810<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3811<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3812 instruction is used to inform the optimizer that a particular portion of the
3813 code is not reachable. This can be used to indicate that the code after a
3814 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3815
3816<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3817<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3818
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3819</div>
3820
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3821</div>
3822
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3823<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3824<h3>
3825 <a name="binaryops">Binary Operations</a>
3826</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3828<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3829
3830<p>Binary operators are used to do most of the computation in a program. They
3831 require two operands of the same type, execute an operation on them, and
3832 produce a single value. The operands might represent multiple data, as is
3833 the case with the <a href="#t_vector">vector</a> data type. The result value
3834 has the same type as its operands.</p>
3835
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3836<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3837
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3838<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3839<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3840 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3841</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3842
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3843<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3845<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3846<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3847 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3848 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3849 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3850 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3851</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3853<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3854<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3856<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857<p>The two arguments to the '<tt>add</tt>' instruction must
3858 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3859 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3861<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3862<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3864<p>If the sum has unsigned overflow, the result returned is the mathematical
3865 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3867<p>Because LLVM integers use a two's complement representation, this instruction
3868 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3869
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3870<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3871 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3872 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3873 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3874 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3876<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3877<pre>
3878 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3881</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3883<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3884<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3885 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3886</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3887
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3888<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3889
3890<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3891<pre>
3892 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3893</pre>
3894
3895<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3896<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3897
3898<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3899<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3901 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3902
3903<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3904<p>The value produced is the floating point sum of the two operands.</p>
3905
3906<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3907<pre>
3908 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3909</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3911</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3913<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3914<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3915 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3916</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3917
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3918<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3920<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3921<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3922 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3923 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3924 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3925 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3928<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3929<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3930 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3931
3932<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933 '<tt>neg</tt>' instruction present in most other intermediate
3934 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3936<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937<p>The two arguments to the '<tt>sub</tt>' instruction must
3938 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3939 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3941<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3942<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3943
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3944<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3946 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948<p>Because LLVM integers use a two's complement representation, this instruction
3949 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3950
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3951<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3952 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3953 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3954 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3955 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3957<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3958<pre>
3959 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3960 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3961</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3963</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3965<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3966<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3967 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3968</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3969
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3970<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3971
3972<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3973<pre>
3974 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3975</pre>
3976
3977<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3978<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3980
3981<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3982 '<tt>fneg</tt>' instruction present in most other intermediate
3983 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3984
3985<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3986<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3988 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3989
3990<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3991<p>The value produced is the floating point difference of the two operands.</p>
3992
3993<h5>Example:</h5>
3994<pre>
3995 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3996 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3997</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3999</div>
4000
4001<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4002<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4003 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4004</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4005
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4006<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4008<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4010 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]4011 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4012 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4013 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4014</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4015
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4016<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4017<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4018
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4019<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020<p>The two arguments to the '<tt>mul</tt>' instruction must
4021 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4022 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4024<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4025<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<p>If the result of the multiplication has unsigned overflow, the result
4028 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
4029 width of the result.</p>
4030
4031<p>Because LLVM integers use a two's complement representation, and the result
4032 is the same width as the operands, this instruction returns the correct
4033 result for both signed and unsigned integers. If a full product
4034 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4035 be sign-extended or zero-extended as appropriate to the width of the full
4036 product.</p>
4037
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4038<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4039 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4040 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4041 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]4042 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4044<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045<pre>
4046 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4048
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4049</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4050
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4051<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4052<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4053 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4054</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4055
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4056<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4057
4058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059<pre>
4060 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4064<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4065
4066<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4067<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4069 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4070
4071<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4072<p>The value produced is the floating point product of the two operands.</p>
4073
4074<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075<pre>
4076 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4077</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4079</div>
4080
4081<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4082<h4>
4083 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4084</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4086<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4087
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4088<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4089<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4090 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4091 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4092</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4094<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4095<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4096
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4097<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4098<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4099 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4100 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4101
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4102<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4103<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4104
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4105<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4107
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4108<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4109
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4110<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4111 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4112 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4113
4114
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4115<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4116<pre>
4117 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4118</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4120</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4122<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4123<h4>
4124 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4125</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4127<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4129<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4130<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4131 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]4132 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4133</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4134
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4135<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4136<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4137
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4138<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4139<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4140 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4141 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4142
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4143<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4144<p>The value produced is the signed integer quotient of the two operands rounded
4145 towards zero.</p>
4146
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4147<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4148 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4149
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4150<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4151 undefined behavior; this is a rare case, but can occur, for example, by doing
4152 a 32-bit division of -2147483648 by -1.</p>
4153
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]4154<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4155 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]4156 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4157
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4158<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159<pre>
4160 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4161</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4162
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4163</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4164
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4165<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4166<h4>
4167 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4168</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4169
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4170<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4171
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4172<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4173<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4174 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4175</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4177<h5>Overview:</h5>
4178<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4179
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4180<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4181<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4183 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4184
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4185<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4186<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4187
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4188<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4189<pre>
4190 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4191</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4193</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4194
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4195<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4196<h4>
4197 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4198</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4200<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4201
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4202<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4203<pre>
4204 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4205</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4207<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4208<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4209 division of its two arguments.</p>
4210
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4211<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4212<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4213 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4214 values. Both arguments must have identical types.</p>
4215
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4216<h5>Semantics:</h5>
4217<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218 This instruction always performs an unsigned division to get the
4219 remainder.</p>
4220
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4221<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4223
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4224<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4225
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4226<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4227<pre>
4228 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4229</pre>
4230
4231</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4232
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4233<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4234<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4235 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4236</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4238<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4239
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4240<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4241<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4242 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4243</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4245<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4247 division of its two operands. This instruction can also take
4248 <a href="#t_vector">vector</a> versions of the values in which case the
4249 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4250
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4251<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4252<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4253 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4254 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4255
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4256<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4257<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4258 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4259 <i>modulo</i> operator (where the result is either zero or has the same sign
4260 as the divisor, <tt>op2</tt>) of a value.
4261 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4262 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4263 Math Forum</a>. For a table of how this is implemented in various languages,
4264 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4265 Wikipedia: modulo operation</a>.</p>
4266
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4267<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4269
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4270<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 Overflow also leads to undefined behavior; this is a rare case, but can
4272 occur, for example, by taking the remainder of a 32-bit division of
4273 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4274 lets srem be implemented using instructions that return both the result of
4275 the division and the remainder.)</p>
4276
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4277<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278<pre>
4279 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4280</pre>
4281
4282</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4283
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4284<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4285<h4>
4286 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4287</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4288
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4289<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4290
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4291<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292<pre>
4293 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4294</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4296<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4298 its two operands.</p>
4299
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4300<h5>Arguments:</h5>
4301<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4303 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4304
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4305<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306<p>This instruction returns the <i>remainder</i> of a division. The remainder
4307 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4308
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4309<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4310<pre>
4311 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4312</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4314</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4315
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4316</div>
4317
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4318<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4319<h3>
4320 <a name="bitwiseops">Bitwise Binary Operations</a>
4321</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4322
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4323<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324
4325<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4326 program. They are generally very efficient instructions and can commonly be
4327 strength reduced from other instructions. They require two operands of the
4328 same type, execute an operation on them, and produce a single value. The
4329 resulting value is the same type as its operands.</p>
4330
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4331<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4332<h4>
4333 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4334</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4336<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4337
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4338<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4340 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4341 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4342 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4343 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4344</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4345
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4346<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4347<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4348 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4349
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4350<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4352 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4353 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4354
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4355<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4357 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4358 is (statically or dynamically) negative or equal to or larger than the number
4359 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4360 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4361 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4362
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4363<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4364 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4365 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4366 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4367 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4368 they would if the shift were expressed as a mul instruction with the same
4369 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4371<h5>Example:</h5>
4372<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4373 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4374 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4375 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4376 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4377 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4378</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4379
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4380</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4381
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4382<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4383<h4>
4384 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4385</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4386
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4387<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4389<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4390<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4391 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4392 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4393</pre>
4394
4395<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4397 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4398
4399<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4400<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4401 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4402 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4403
4404<h5>Semantics:</h5>
4405<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4406 significant bits of the result will be filled with zero bits after the shift.
4407 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4408 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4409 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4410 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4411
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4412<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4413 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4414 shifted out are non-zero.</p>
4415
4416
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4417<h5>Example:</h5>
4418<pre>
4419 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4420 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4421 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4422 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4423 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4424 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4425</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4426
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4427</div>
4428
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4429<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4430<h4>
4431 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4432</h4>
4433
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4434<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4435
4436<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4437<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4438 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4439 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4440</pre>
4441
4442<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4444 operand shifted to the right a specified number of bits with sign
4445 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4446
4447<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4448<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4449 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4450 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4451
4452<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453<p>This instruction always performs an arithmetic shift right operation, The
4454 most significant bits of the result will be filled with the sign bit
4455 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4456 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4457 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4458 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4459
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4460<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4461 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4462 shifted out are non-zero.</p>
4463
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4464<h5>Example:</h5>
4465<pre>
4466 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4467 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4468 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4469 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4470 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4471 &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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4472</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4473
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4474</div>
4475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4476<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4477<h4>
4478 <a name="i_and">'<tt>and</tt>' Instruction</a>
4479</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4481<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4482
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4483<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4484<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4485 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4486</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4487
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4488<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4489<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4490 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4491
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4492<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4493<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4495 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4497<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4498<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4500<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4501 <tbody>
4502 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4503 <th>In0</th>
4504 <th>In1</th>
4505 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4506 </tr>
4507 <tr>
4508 <td>0</td>
4509 <td>0</td>
4510 <td>0</td>
4511 </tr>
4512 <tr>
4513 <td>0</td>
4514 <td>1</td>
4515 <td>0</td>
4516 </tr>
4517 <tr>
4518 <td>1</td>
4519 <td>0</td>
4520 <td>0</td>
4521 </tr>
4522 <tr>
4523 <td>1</td>
4524 <td>1</td>
4525 <td>1</td>
4526 </tr>
4527 </tbody>
4528</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4530<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4531<pre>
4532 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4533 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4534 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4535</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4536</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4537<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4538<h4>
4539 <a name="i_or">'<tt>or</tt>' Instruction</a>
4540</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4541
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4542<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4543
4544<h5>Syntax:</h5>
4545<pre>
4546 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4547</pre>
4548
4549<h5>Overview:</h5>
4550<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4551 two operands.</p>
4552
4553<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4554<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4555 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4556 values. Both arguments must have identical types.</p>
4557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4558<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4559<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4560
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4561<table border="1" cellspacing="0" cellpadding="4">
4562 <tbody>
4563 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4564 <th>In0</th>
4565 <th>In1</th>
4566 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4567 </tr>
4568 <tr>
4569 <td>0</td>
4570 <td>0</td>
4571 <td>0</td>
4572 </tr>
4573 <tr>
4574 <td>0</td>
4575 <td>1</td>
4576 <td>1</td>
4577 </tr>
4578 <tr>
4579 <td>1</td>
4580 <td>0</td>
4581 <td>1</td>
4582 </tr>
4583 <tr>
4584 <td>1</td>
4585 <td>1</td>
4586 <td>1</td>
4587 </tr>
4588 </tbody>
4589</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4591<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4592<pre>
4593 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4594 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4595 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4596</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4598</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4600<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4601<h4>
4602 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4603</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4604
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4605<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4607<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4608<pre>
4609 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4610</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4612<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4614 its two operands. The <tt>xor</tt> is used to implement the "one's
4615 complement" operation, which is the "~" operator in C.</p>
4616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4617<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4618<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4619 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4620 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4622<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4623<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4624
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4625<table border="1" cellspacing="0" cellpadding="4">
4626 <tbody>
4627 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4628 <th>In0</th>
4629 <th>In1</th>
4630 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4631 </tr>
4632 <tr>
4633 <td>0</td>
4634 <td>0</td>
4635 <td>0</td>
4636 </tr>
4637 <tr>
4638 <td>0</td>
4639 <td>1</td>
4640 <td>1</td>
4641 </tr>
4642 <tr>
4643 <td>1</td>
4644 <td>0</td>
4645 <td>1</td>
4646 </tr>
4647 <tr>
4648 <td>1</td>
4649 <td>1</td>
4650 <td>0</td>
4651 </tr>
4652 </tbody>
4653</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4655<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656<pre>
4657 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4658 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4659 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4660 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4663</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4664
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4665</div>
4666
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4667<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4668<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4669 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4670</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4671
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4672<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4673
4674<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675 target-independent manner. These instructions cover the element-access and
4676 vector-specific operations needed to process vectors effectively. While LLVM
4677 does directly support these vector operations, many sophisticated algorithms
4678 will want to use target-specific intrinsics to take full advantage of a
4679 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4680
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4681<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4682<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4683 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4684</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4686<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4687
4688<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4689<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4690 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4691</pre>
4692
4693<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4694<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4695 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4696
4697
4698<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4699<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4700 of <a href="#t_vector">vector</a> type. The second operand is an index
4701 indicating the position from which to extract the element. The index may be
4702 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4703
4704<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705<p>The result is a scalar of the same type as the element type of
4706 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4707 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4708 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4709
4710<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4711<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4712 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4713</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4714
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4716
4717<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4718<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4719 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4720</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4721
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4722<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4723
4724<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4725<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4726 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4727</pre>
4728
4729<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4731 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4732
4733<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4735 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4736 whose type must equal the element type of the first operand. The third
4737 operand is an index indicating the position at which to insert the value.
4738 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4739
4740<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4742 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4743 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4744 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4745
4746<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4747<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4748 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4749</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4751</div>
4752
4753<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4754<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4755 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4756</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4757
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4758<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4759
4760<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4761<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4762 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4763</pre>
4764
4765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4766<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4767 from two input vectors, returning a vector with the same element type as the
4768 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4769
4770<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4771<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsb5a1bf42012-06-14 14:58:28 +0000[diff] [blame]4772 with the same type. The third argument is a shuffle mask whose
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773 element type is always 'i32'. The result of the instruction is a vector
4774 whose length is the same as the shuffle mask and whose element type is the
4775 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4777<p>The shuffle mask operand is required to be a constant vector with either
4778 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4779
4780<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781<p>The elements of the two input vectors are numbered from left to right across
4782 both of the vectors. The shuffle mask operand specifies, for each element of
4783 the result vector, which element of the two input vectors the result element
4784 gets. The element selector may be undef (meaning "don't care") and the
4785 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4786
4787<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4788<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4789 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4790 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4791 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4792 &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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4793 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4794 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4795 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4796 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4797</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4798
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4801</div>
4802
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4803<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4804<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4805 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4806</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4807
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4808<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4809
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4810<p>LLVM supports several instructions for working with
4811 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4812
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4813<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4814<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4815 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4816</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4817
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4818<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4819
4820<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4821<pre>
4822 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4823</pre>
4824
4825<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4826<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4827 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4828
4829<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4830<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4831 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4832 <a href="#t_array">array</a> type. The operands are constant indices to
4833 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4835 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4836 <ul>
4837 <li>Since the value being indexed is not a pointer, the first index is
4838 omitted and assumed to be zero.</li>
4839 <li>At least one index must be specified.</li>
4840 <li>Not only struct indices but also array indices must be in
4841 bounds.</li>
4842 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4843
4844<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4845<p>The result is the value at the position in the aggregate specified by the
4846 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4847
4848<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4849<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4850 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4851</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4852
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4854
4855<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4856<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4857 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4858</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4859
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4860<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4861
4862<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4863<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4864 &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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4865</pre>
4866
4867<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4868<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4869 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4870
4871<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4872<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4873 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4874 <a href="#t_array">array</a> type. The second operand is a first-class
4875 value to insert. The following operands are constant indices indicating
4876 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4877 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4878 value to insert must have the same type as the value identified by the
4879 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4880
4881<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4883 that of <tt>val</tt> except that the value at the position specified by the
4884 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4885
4886<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4887<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4888 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4889 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4890 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4891</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4892
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4893</div>
4894
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4895</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4896
4897<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4898<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4899 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4900</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4901
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4902<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4904<p>A key design point of an SSA-based representation is how it represents
4905 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4906 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4907 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4910<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4911 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4912</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4914<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4916<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4917<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4918 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4919</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4921<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4922<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923 currently executing function, to be automatically released when this function
4924 returns to its caller. The object is always allocated in the generic address
4925 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4927<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4928<p>The '<tt>alloca</tt>' instruction
4929 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4930 runtime stack, returning a pointer of the appropriate type to the program.
4931 If "NumElements" is specified, it is the number of elements allocated,
4932 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4933 specified, the value result of the allocation is guaranteed to be aligned to
4934 at least that boundary. If not specified, or if zero, the target can choose
4935 to align the allocation on any convenient boundary compatible with the
4936 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4938<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4940<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4941<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4943 memory is automatically released when the function returns. The
4944 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4945 variables that must have an address available. When the function returns
4946 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]4947 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4948 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4949 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewycky75d05e62012-03-18 09:35:50 +0000[diff] [blame]4950 not specified.</p>
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4951
4952<p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4954<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4955<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4956 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4957 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4958 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4959 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4960</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4962</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4964<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4965<h4>
4966 <a name="i_load">'<tt>load</tt>' Instruction</a>
4967</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4968
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4969<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4970
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4971<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4972<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4973 &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 Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4974 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4975 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976</pre>
4977
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4978<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4979<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4980
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4981<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4982<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4983 from which to load. The pointer must point to
4984 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4985 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4986 number or order of execution of this <tt>load</tt> with other <a
4987 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4988
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4989<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4990 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4991 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4992 not valid on <code>load</code> instructions. Atomic loads produce <a
4993 href="#memorymodel">defined</a> results when they may see multiple atomic
4994 stores. The type of the pointee must be an integer type whose bit width
4995 is a power of two greater than or equal to eight and less than or equal
4996 to a target-specific size limit. <code>align</code> must be explicitly
4997 specified on atomic loads, and the load has undefined behavior if the
4998 alignment is not set to a value which is at least the size in bytes of
4999 the pointee. <code>!nontemporal</code> does not have any defined semantics
5000 for atomic loads.</p>
5001
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5002<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5003 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5004 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5005 alignment for the target. It is the responsibility of the code emitter to
5006 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5007 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5008 produce less efficient code. An alignment of 1 is always safe.</p>
5009
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5010<p>The optional <tt>!nontemporal</tt> metadata must reference a single
5011 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5012 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5013 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
5014 and code generator that this load is not expected to be reused in the cache.
5015 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5016 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5017
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]5018<p>The optional <tt>!invariant.load</tt> metadata must reference a single
5019 metatadata name &lt;index&gt; corresponding to a metadata node with no
5020 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
5021 instruction tells the optimizer and code generator that this load address
5022 points to memory which does not change value during program execution.
5023 The optimizer may then move this load around, for example, by hoisting it
5024 out of loops using loop invariant code motion.</p>
5025
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5026<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027<p>The location of memory pointed to is loaded. If the value being loaded is of
5028 scalar type then the number of bytes read does not exceed the minimum number
5029 of bytes needed to hold all bits of the type. For example, loading an
5030 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5031 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5032 is undefined if the value was not originally written using a store of the
5033 same type.</p>
5034
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5035<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036<pre>
5037 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5038 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5039 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5040</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5042</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5044<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5045<h4>
5046 <a name="i_store">'<tt>store</tt>' Instruction</a>
5047</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5049<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5050
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5051<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5053 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>
5054 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5055</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5057<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5058<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5060<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5062 and an address at which to store it. The type of the
5063 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5064 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5065 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5066 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5067 order of execution of this <tt>store</tt> with other <a
5068 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5069
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5070<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5071 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5072 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5073 valid on <code>store</code> instructions. Atomic loads produce <a
5074 href="#memorymodel">defined</a> results when they may see multiple atomic
5075 stores. The type of the pointee must be an integer type whose bit width
5076 is a power of two greater than or equal to eight and less than or equal
5077 to a target-specific size limit. <code>align</code> must be explicitly
5078 specified on atomic stores, and the store has undefined behavior if the
5079 alignment is not set to a value which is at least the size in bytes of
5080 the pointee. <code>!nontemporal</code> does not have any defined semantics
5081 for atomic stores.</p>
5082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5083<p>The optional constant "align" argument specifies the alignment of the
5084 operation (that is, the alignment of the memory address). A value of 0 or an
5085 omitted "align" argument means that the operation has the preferential
5086 alignment for the target. It is the responsibility of the code emitter to
5087 ensure that the alignment information is correct. Overestimating the
5088 alignment results in an undefined behavior. Underestimating the alignment may
5089 produce less efficient code. An alignment of 1 is always safe.</p>
5090
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5091<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5092 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5093 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5094 instruction tells the optimizer and code generator that this load is
5095 not expected to be reused in the cache. The code generator may
5096 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5097 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5098
5099
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5100<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5102 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5103 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5104 does not exceed the minimum number of bytes needed to hold all bits of the
5105 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5106 writing a value of a type like <tt>i20</tt> with a size that is not an
5107 integral number of bytes, it is unspecified what happens to the extra bits
5108 that do not belong to the type, but they will typically be overwritten.</p>
5109
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5110<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5111<pre>
5112 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]5113 store i32 3, i32* %ptr <i>; yields {void}</i>
5114 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5115</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5117</div>
5118
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5119<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5120<h4>
5121<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5122</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5123
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5124<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5125
5126<h5>Syntax:</h5>
5127<pre>
5128 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5129</pre>
5130
5131<h5>Overview:</h5>
5132<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5133between operations.</p>
5134
5135<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5136href="#ordering">ordering</a> argument which defines what
5137<i>synchronizes-with</i> edges they add. They can only be given
5138<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5139<code>seq_cst</code> orderings.</p>
5140
5141<h5>Semantics:</h5>
5142<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5143semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5144<code>acquire</code> ordering semantics if and only if there exist atomic
5145operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5146<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5147<var>X</var> modifies <var>M</var> (either directly or through some side effect
5148of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5149<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5150<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5151than an explicit <code>fence</code>, one (but not both) of the atomic operations
5152<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5153<code>acquire</code> (resp.) ordering constraint and still
5154<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5155<i>happens-before</i> edge.</p>
5156
5157<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5158having both <code>acquire</code> and <code>release</code> semantics specified
5159above, participates in the global program order of other <code>seq_cst</code>
5160operations and/or fences.</p>
5161
5162<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5163specifies that the fence only synchronizes with other fences in the same
5164thread. (This is useful for interacting with signal handlers.)</p>
5165
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5166<h5>Example:</h5>
5167<pre>
5168 fence acquire <i>; yields {void}</i>
5169 fence singlethread seq_cst <i>; yields {void}</i>
5170</pre>
5171
5172</div>
5173
5174<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5175<h4>
5176<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5177</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5178
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5179<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5180
5181<h5>Syntax:</h5>
5182<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5183 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5184</pre>
5185
5186<h5>Overview:</h5>
5187<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5188It loads a value in memory and compares it to a given value. If they are
5189equal, it stores a new value into the memory.</p>
5190
5191<h5>Arguments:</h5>
5192<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5193address to operate on, a value to compare to the value currently be at that
5194address, and a new value to place at that address if the compared values are
5195equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5196bit width is a power of two greater than or equal to eight and less than
5197or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5198'<var>&lt;new&gt;</var>' must have the same type, and the type of
5199'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5200<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5201optimizer is not allowed to modify the number or order of execution
5202of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5203operations</a>.</p>
5204
5205<!-- FIXME: Extend allowed types. -->
5206
5207<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5208<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5209
5210<p>The optional "<code>singlethread</code>" argument declares that the
5211<code>cmpxchg</code> is only atomic with respect to code (usually signal
5212handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5213cmpxchg is atomic with respect to all other code in the system.</p>
5214
5215<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5216the size in memory of the operand.
5217
5218<h5>Semantics:</h5>
5219<p>The contents of memory at the location specified by the
5220'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5221'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5222'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5223is returned.
5224
5225<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5226purpose of identifying <a href="#release_sequence">release sequences</a>. A
5227failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5228parameter determined by dropping any <code>release</code> part of the
5229<code>cmpxchg</code>'s ordering.</p>
5230
5231<!--
5232FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5233optimization work on ARM.)
5234
5235FIXME: Is a weaker ordering constraint on failure helpful in practice?
5236-->
5237
5238<h5>Example:</h5>
5239<pre>
5240entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5241 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5242 <a href="#i_br">br</a> label %loop
5243
5244loop:
5245 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5246 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5247 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5248 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5249 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5250
5251done:
5252 ...
5253</pre>
5254
5255</div>
5256
5257<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5258<h4>
5259<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5260</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5261
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5262<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5263
5264<h5>Syntax:</h5>
5265<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5266 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5267</pre>
5268
5269<h5>Overview:</h5>
5270<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5271
5272<h5>Arguments:</h5>
5273<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5274operation to apply, an address whose value to modify, an argument to the
5275operation. The operation must be one of the following keywords:</p>
5276<ul>
5277 <li>xchg</li>
5278 <li>add</li>
5279 <li>sub</li>
5280 <li>and</li>
5281 <li>nand</li>
5282 <li>or</li>
5283 <li>xor</li>
5284 <li>max</li>
5285 <li>min</li>
5286 <li>umax</li>
5287 <li>umin</li>
5288</ul>
5289
5290<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5291bit width is a power of two greater than or equal to eight and less than
5292or equal to a target-specific size limit. The type of the
5293'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5294If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5295optimizer is not allowed to modify the number or order of execution of this
5296<code>atomicrmw</code> with other <a href="#volatile">volatile
5297 operations</a>.</p>
5298
5299<!-- FIXME: Extend allowed types. -->
5300
5301<h5>Semantics:</h5>
5302<p>The contents of memory at the location specified by the
5303'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5304back. The original value at the location is returned. The modification is
5305specified by the <var>operation</var> argument:</p>
5306
5307<ul>
5308 <li>xchg: <code>*ptr = val</code></li>
5309 <li>add: <code>*ptr = *ptr + val</code></li>
5310 <li>sub: <code>*ptr = *ptr - val</code></li>
5311 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5312 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5313 <li>or: <code>*ptr = *ptr | val</code></li>
5314 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5315 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5316 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5317 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5318 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5319</ul>
5320
5321<h5>Example:</h5>
5322<pre>
5323 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5324</pre>
5325
5326</div>
5327
5328<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5329<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5330 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5331</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5332
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5333<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5334
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5335<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5336<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5337 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5338 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5339 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5340</pre>
5341
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5342<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5343<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5344 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5345 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5346
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5347<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5348<p>The first argument is always a pointer or a vector of pointers,
5349 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5350 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5351 elements of the aggregate object are indexed. The interpretation of each
5352 index is dependent on the type being indexed into. The first index always
5353 indexes the pointer value given as the first argument, the second index
5354 indexes a value of the type pointed to (not necessarily the value directly
5355 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5356 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5357 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5358 can never be pointers, since that would require loading the pointer before
5359 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5360
5361<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5362 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5363 integer <b>constants</b> are allowed. When indexing into an array, pointer
5364 or vector, integers of any width are allowed, and they are not required to be
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5365 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5367<p>For example, let's consider a C code fragment and how it gets compiled to
5368 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5369
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5370<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5371struct RT {
5372 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5373 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5374 char C;
5375};
5376struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5377 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5378 double Y;
5379 struct RT Z;
5380};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5381
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5382int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5383 return &amp;s[1].Z.B[5][13];
5384}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5385</pre>
5386
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5387<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5388
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5389<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5390%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5391%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5392
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5393define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5394entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5395 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5396 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5397}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5398</pre>
5399
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5400<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5401<p>In the example above, the first index is indexing into the
5402 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5403 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5404 structure. The second index indexes into the third element of the structure,
5405 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5406 type, another structure. The third index indexes into the second element of
5407 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5408 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5409 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5410 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5411
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5412<p>Note that it is perfectly legal to index partially through a structure,
5413 returning a pointer to an inner element. Because of this, the LLVM code for
5414 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5415
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5416<pre class="doc_code">
5417define i32* @foo(%struct.ST* %s) {
5418 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5419 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5420 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5421 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5422 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5423 ret i32* %t5
5424}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5425</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5426
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5427<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5428 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5429 base pointer is not an <i>in bounds</i> address of an allocated object,
5430 or if any of the addresses that would be formed by successive addition of
5431 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5432 precise signed arithmetic are not an <i>in bounds</i> address of that
5433 allocated object. The <i>in bounds</i> addresses for an allocated object
5434 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5435 byte past the end.
5436 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5437 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5438
5439<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5440 the base address with silently-wrapping two's complement arithmetic. If the
5441 offsets have a different width from the pointer, they are sign-extended or
5442 truncated to the width of the pointer. The result value of the
5443 <tt>getelementptr</tt> may be outside the object pointed to by the base
5444 pointer. The result value may not necessarily be used to access memory
5445 though, even if it happens to point into allocated storage. See the
5446 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5447 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5448
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5449<p>The getelementptr instruction is often confusing. For some more insight into
5450 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5451
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5452<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5453<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5454 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5455 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5456 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5457 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5458 <i>; yields i8*:eptr</i>
5459 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5460 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5461 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5462</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5464<p>In cases where the pointer argument is a vector of pointers, only a
5465 single index may be used, and the number of vector elements has to be
5466 the same. For example: </p>
5467<pre class="doc_code">
5468 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5469</pre>
5470
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5471</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5472
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5473</div>
5474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5475<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5476<h3>
5477 <a name="convertops">Conversion Operations</a>
5478</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5480<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5481
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5482<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5483 which all take a single operand and a type. They perform various bit
5484 conversions on the operand.</p>
5485
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5486<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5487<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5488 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5489</h4>
5490
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5491<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5492
5493<h5>Syntax:</h5>
5494<pre>
5495 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5496</pre>
5497
5498<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5500 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5501
5502<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5503<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5504 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5505 of the same number of integers.
5506 The bit size of the <tt>value</tt> must be larger than
5507 the bit size of the destination type, <tt>ty2</tt>.
5508 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5509
5510<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5511<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5512 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5513 source size must be larger than the destination size, <tt>trunc</tt> cannot
5514 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5515
5516<h5>Example:</h5>
5517<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5518 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5519 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5520 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5521 %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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5523
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5524</div>
5525
5526<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5527<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5528 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5529</h4>
5530
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5531<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Syntax:</h5>
5534<pre>
5535 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5536</pre>
5537
5538<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5539<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5540 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5541
5542
5543<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5544<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5545 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5546 of the same number of integers.
5547 The bit size of the <tt>value</tt> must be smaller than
5548 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5549 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5550
5551<h5>Semantics:</h5>
5552<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5553 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5554
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5555<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5556
5557<h5>Example:</h5>
5558<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5559 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5560 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5561 %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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5562</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5563
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5564</div>
5565
5566<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5567<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5568 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5569</h4>
5570
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5571<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5572
5573<h5>Syntax:</h5>
5574<pre>
5575 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5576</pre>
5577
5578<h5>Overview:</h5>
5579<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5580
5581<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5582<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5583 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5584 of the same number of integers.
5585 The bit size of the <tt>value</tt> must be smaller than
5586 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5587 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5588
5589<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5590<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5591 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5592 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5593
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5594<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5595
5596<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5597<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5598 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5599 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5600 %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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5601</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5602
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5603</div>
5604
5605<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5606<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5607 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5608</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5609
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5610<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5611
5612<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5613<pre>
5614 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5615</pre>
5616
5617<h5>Overview:</h5>
5618<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5619 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5620
5621<h5>Arguments:</h5>
5622<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5623 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5624 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5625 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5626 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5627
5628<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5630 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631 <a href="#t_floating">floating point</a> type. If the value cannot fit
5632 within the destination type, <tt>ty2</tt>, then the results are
5633 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5634
5635<h5>Example:</h5>
5636<pre>
5637 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5638 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5639</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5641</div>
5642
5643<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5644<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5645 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5646</h4>
5647
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5648<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5649
5650<h5>Syntax:</h5>
5651<pre>
5652 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5653</pre>
5654
5655<h5>Overview:</h5>
5656<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5657 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5658
5659<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5660<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5661 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5662 a <a href="#t_floating">floating point</a> type to cast it to. The source
5663 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5664
5665<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5666<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5667 <a href="#t_floating">floating point</a> type to a larger
5668 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5669 used to make a <i>no-op cast</i> because it always changes bits. Use
5670 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5671
5672<h5>Example:</h5>
5673<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5674 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5675 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5676</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5677
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5678</div>
5679
5680<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5681<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5682 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5683</h4>
5684
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5685<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5686
5687<h5>Syntax:</h5>
5688<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5689 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5690</pre>
5691
5692<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5693<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5694 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5695
5696<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5697<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5698 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5699 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5700 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5701 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5702
5703<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5704<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5705 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5706 towards zero) unsigned integer value. If the value cannot fit
5707 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5708
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5709<h5>Example:</h5>
5710<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5711 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5712 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5713 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5714</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5715
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5716</div>
5717
5718<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5719<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5720 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5721</h4>
5722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5723<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5724
5725<h5>Syntax:</h5>
5726<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5727 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5728</pre>
5729
5730<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5731<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732 <a href="#t_floating">floating point</a> <tt>value</tt> to
5733 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5734
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5735<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5736<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5737 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5738 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5739 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5740 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5741
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5742<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5743<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5744 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5745 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5746 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5747
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5748<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5749<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5750 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5751 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5752 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5753</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5754
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5755</div>
5756
5757<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5758<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5759 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5760</h4>
5761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5762<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5763
5764<h5>Syntax:</h5>
5765<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5766 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5767</pre>
5768
5769<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5770<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5771 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5772
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5773<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5774<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5776 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5777 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5778 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5779
5780<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5781<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5782 integer quantity and converts it to the corresponding floating point
5783 value. If the value cannot fit in the floating point value, the results are
5784 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5785
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5786<h5>Example:</h5>
5787<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5788 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5789 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5790</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5792</div>
5793
5794<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5795<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5796 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5797</h4>
5798
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5799<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5800
5801<h5>Syntax:</h5>
5802<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5803 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5804</pre>
5805
5806<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5808 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5809
5810<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5811<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5813 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5814 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5815 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5816
5817<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5818<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5819 quantity and converts it to the corresponding floating point value. If the
5820 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5821
5822<h5>Example:</h5>
5823<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5824 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5825 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5826</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5828</div>
5829
5830<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5831<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5832 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5833</h4>
5834
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5835<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5836
5837<h5>Syntax:</h5>
5838<pre>
5839 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5840</pre>
5841
5842<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5843<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5844 pointers <tt>value</tt> to
5845 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5846
5847<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5849 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5850 pointers, and a type to cast it to
5851 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5852 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5853
5854<h5>Semantics:</h5>
5855<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5857 truncating or zero extending that value to the size of the integer type. If
5858 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5859 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5860 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5861 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5862
5863<h5>Example:</h5>
5864<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5865 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5866 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5867 %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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5868</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5870</div>
5871
5872<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5873<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5874 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5875</h4>
5876
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5877<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5878
5879<h5>Syntax:</h5>
5880<pre>
5881 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5882</pre>
5883
5884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5886 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5887
5888<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5889<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890 value to cast, and a type to cast it to, which must be a
5891 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5892
5893<h5>Semantics:</h5>
5894<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5896 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5897 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5898 than the size of a pointer then a zero extension is done. If they are the
5899 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5900
5901<h5>Example:</h5>
5902<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5903 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5904 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5905 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5906 %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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5908
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5909</div>
5910
5911<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5912<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5913 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5914</h4>
5915
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5916<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5917
5918<h5>Syntax:</h5>
5919<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5920 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5924<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5925 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5926
5927<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5928<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5929 non-aggregate first class value, and a type to cast it to, which must also be
5930 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5931 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5932 identical. If the source type is a pointer, the destination type must also be
5933 a pointer. This instruction supports bitwise conversion of vectors to
5934 integers and to vectors of other types (as long as they have the same
5935 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5936
5937<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5938<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5939 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5940 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5941 stored to memory and read back as type <tt>ty2</tt>.
5942 Pointer (or vector of pointers) types may only be converted to other pointer
5943 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5944 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5945 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5946
5947<h5>Example:</h5>
5948<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5949 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5950 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5951 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5952 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5955</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5956
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5957</div>
5958
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5959<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5960<h3>
5961 <a name="otherops">Other Operations</a>
5962</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5963
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5964<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965
5966<p>The instructions in this category are the "miscellaneous" instructions, which
5967 defy better classification.</p>
5968
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5969<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5970<h4>
5971 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5972</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5973
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5974<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5975
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5976<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5977<pre>
5978 &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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5979</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5980
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5981<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5982<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5983 boolean values based on comparison of its two integer, integer vector,
5984 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5985
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5986<h5>Arguments:</h5>
5987<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5988 the condition code indicating the kind of comparison to perform. It is not a
5989 value, just a keyword. The possible condition code are:</p>
5990
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5991<ol>
5992 <li><tt>eq</tt>: equal</li>
5993 <li><tt>ne</tt>: not equal </li>
5994 <li><tt>ugt</tt>: unsigned greater than</li>
5995 <li><tt>uge</tt>: unsigned greater or equal</li>
5996 <li><tt>ult</tt>: unsigned less than</li>
5997 <li><tt>ule</tt>: unsigned less or equal</li>
5998 <li><tt>sgt</tt>: signed greater than</li>
5999 <li><tt>sge</tt>: signed greater or equal</li>
6000 <li><tt>slt</tt>: signed less than</li>
6001 <li><tt>sle</tt>: signed less or equal</li>
6002</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6003
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]6004<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
6006 typed. They must also be identical types.</p>
6007
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6008<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6009<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
6010 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6011 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012 result, as follows:</p>
6013
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6014<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6015 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6016 <tt>false</tt> otherwise. No sign interpretation is necessary or
6017 performed.</li>
6018
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6019 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6020 <tt>false</tt> otherwise. No sign interpretation is necessary or
6021 performed.</li>
6022
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6023 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6025
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6026 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6027 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6028 to <tt>op2</tt>.</li>
6029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6030 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6031 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6032
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6033 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6034 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6036 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6039 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6040 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6041 to <tt>op2</tt>.</li>
6042
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6043 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6044 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6045
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6046 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6047 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6048</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6050<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6051 values are compared as if they were integers.</p>
6052
6053<p>If the operands are integer vectors, then they are compared element by
6054 element. The result is an <tt>i1</tt> vector with the same number of elements
6055 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6056
6057<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058<pre>
6059 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6060 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6061 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6062 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6063 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6064 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6065</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6066
6067<p>Note that the code generator does not yet support vector types with
6068 the <tt>icmp</tt> instruction.</p>
6069
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6070</div>
6071
6072<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6073<h4>
6074 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6075</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6076
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6077<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6079<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080<pre>
6081 &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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6082</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6083
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6084<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6085<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6086 values based on comparison of its operands.</p>
6087
6088<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6089(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6090
6091<p>If the operands are floating point vectors, then the result type is a vector
6092 of boolean with the same number of elements as the operands being
6093 compared.</p>
6094
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6095<h5>Arguments:</h5>
6096<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6097 the condition code indicating the kind of comparison to perform. It is not a
6098 value, just a keyword. The possible condition code are:</p>
6099
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6100<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6101 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6102 <li><tt>oeq</tt>: ordered and equal</li>
6103 <li><tt>ogt</tt>: ordered and greater than </li>
6104 <li><tt>oge</tt>: ordered and greater than or equal</li>
6105 <li><tt>olt</tt>: ordered and less than </li>
6106 <li><tt>ole</tt>: ordered and less than or equal</li>
6107 <li><tt>one</tt>: ordered and not equal</li>
6108 <li><tt>ord</tt>: ordered (no nans)</li>
6109 <li><tt>ueq</tt>: unordered or equal</li>
6110 <li><tt>ugt</tt>: unordered or greater than </li>
6111 <li><tt>uge</tt>: unordered or greater than or equal</li>
6112 <li><tt>ult</tt>: unordered or less than </li>
6113 <li><tt>ule</tt>: unordered or less than or equal</li>
6114 <li><tt>une</tt>: unordered or not equal</li>
6115 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6116 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6117</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6118
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6119<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6120 <i>unordered</i> means that either operand may be a QNAN.</p>
6121
6122<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6123 a <a href="#t_floating">floating point</a> type or
6124 a <a href="#t_vector">vector</a> of floating point type. They must have
6125 identical types.</p>
6126
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6127<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]6128<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6129 according to the condition code given as <tt>cond</tt>. If the operands are
6130 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6131 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6132 follows:</p>
6133
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6134<ol>
6135 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6137 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6138 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6139
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6140 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6141 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6142
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6143 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6144 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6145
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6146 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6147 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6148
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6149 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6150 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6151
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6152 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6153 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6154
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6155 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6156
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6157 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6158 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6159
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6160 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6161 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6162
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6163 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6164 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6165
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6166 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6168
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6169 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6170 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6171
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6172 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6174
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6175 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6176
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6177 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6178</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6179
6180<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181<pre>
6182 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6183 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6184 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6185 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6186</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6187
6188<p>Note that the code generator does not yet support vector types with
6189 the <tt>fcmp</tt> instruction.</p>
6190
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6191</div>
6192
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6193<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6194<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6195 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6196</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6197
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6198<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6199
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6200<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6201<pre>
6202 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6203</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6204
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6206<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6207 SSA graph representing the function.</p>
6208
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210<p>The type of the incoming values is specified with the first type field. After
6211 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6212 one pair for each predecessor basic block of the current block. Only values
6213 of <a href="#t_firstclass">first class</a> type may be used as the value
6214 arguments to the PHI node. Only labels may be used as the label
6215 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6216
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6217<p>There must be no non-phi instructions between the start of a basic block and
6218 the PHI instructions: i.e. PHI instructions must be first in a basic
6219 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6220
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6222 occur on the edge from the corresponding predecessor block to the current
6223 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6224 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6225
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6226<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6227<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6228 specified by the pair corresponding to the predecessor basic block that
6229 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6231<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6232<pre>
6233Loop: ; Infinite loop that counts from 0 on up...
6234 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6235 %nextindvar = add i32 %indvar, 1
6236 br label %Loop
6237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6239</div>
6240
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6241<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6242<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6243 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6244</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6245
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6246<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6247
6248<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6249<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6250 &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>
6251
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6252 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6253</pre>
6254
6255<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6256<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6257 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6258
6259
6260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6261<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6262 values indicating the condition, and two values of the
6263 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6264 vectors and the condition is a scalar, then entire vectors are selected, not
6265 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6266
6267<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6268<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6269 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6270
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6271<p>If the condition is a vector of i1, then the value arguments must be vectors
6272 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6273
6274<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6275<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6276 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6277</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6278
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6279</div>
6280
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6281<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6282<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6283 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6284</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6285
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6286<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6288<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6289<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6290 &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 Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6291</pre>
6292
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6293<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6294<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6296<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6297<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6298
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6299<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6300 <li>The optional "tail" marker indicates that the callee function does not
6301 access any allocas or varargs in the caller. Note that calls may be
6302 marked "tail" even if they do not occur before
6303 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6304 present, the function call is eligible for tail call optimization,
6305 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6306 optimized into a jump</a>. The code generator may optimize calls marked
6307 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6308 sibling call optimization</a> when the caller and callee have
6309 matching signatures, or 2) forced tail call optimization when the
6310 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6311 <ul>
6312 <li>Caller and callee both have the calling
6313 convention <tt>fastcc</tt>.</li>
6314 <li>The call is in tail position (ret immediately follows call and ret
6315 uses value of call or is void).</li>
6316 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6317 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6318 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6319 constraints are met.</a></li>
6320 </ul>
6321 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6322
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6324 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6325 defaults to using C calling conventions. The calling convention of the
6326 call must match the calling convention of the target function, or else the
6327 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6328
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6329 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6330 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6331 '<tt>inreg</tt>' attributes are valid here.</li>
6332
6333 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6334 type of the return value. Functions that return no value are marked
6335 <tt><a href="#t_void">void</a></tt>.</li>
6336
6337 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6338 being invoked. The argument types must match the types implied by this
6339 signature. This type can be omitted if the function is not varargs and if
6340 the function type does not return a pointer to a function.</li>
6341
6342 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6343 be invoked. In most cases, this is a direct function invocation, but
6344 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6345 to function value.</li>
6346
6347 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6348 signature argument types and parameter attributes. All arguments must be
6349 of <a href="#t_firstclass">first class</a> type. If the function
6350 signature indicates the function accepts a variable number of arguments,
6351 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6352
6353 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6354 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6355 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6356</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6358<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6359<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6360 a specified function, with its incoming arguments bound to the specified
6361 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6362 function, control flow continues with the instruction after the function
6363 call, and the return value of the function is bound to the result
6364 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6366<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6367<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6368 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6369 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6370 %X = tail call i32 @foo() <i>; yields i32</i>
6371 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6372 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6373
6374 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6375 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6376 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6377 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6378 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6379 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6380</pre>
6381
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6382<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6383standard C99 library as being the C99 library functions, and may perform
6384optimizations or generate code for them under that assumption. This is
6385something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6386freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6387
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6388</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6389
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6390<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6391<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6392 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6393</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6394
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6395<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6396
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6397<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6398<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6399 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6400</pre>
6401
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6402<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6403<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6404 the "variable argument" area of a function call. It is used to implement the
6405 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6406
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6407<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6409 argument. It returns a value of the specified argument type and increments
6410 the <tt>va_list</tt> to point to the next argument. The actual type
6411 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6412
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6413<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6414<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6415 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6416 to the next argument. For more information, see the variable argument
6417 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6418
6419<p>It is legal for this instruction to be called in a function which does not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6420 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6421 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6422
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6423<p><tt>va_arg</tt> is an LLVM instruction instead of
6424 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6425 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6426
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6427<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6428<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6429
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6430<p>Note that the code generator does not yet fully support va_arg on many
6431 targets. Also, it does not currently support va_arg with aggregate types on
6432 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6433
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6434</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6435
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6436<!-- _______________________________________________________________________ -->
6437<h4>
6438 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6439</h4>
6440
6441<div>
6442
6443<h5>Syntax:</h5>
6444<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6445 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6446 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6447
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6448 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6449 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6450</pre>
6451
6452<h5>Overview:</h5>
6453<p>The '<tt>landingpad</tt>' instruction is used by
6454 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6455 system</a> to specify that a basic block is a landing pad &mdash; one where
6456 the exception lands, and corresponds to the code found in the
6457 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6458 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6459 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6460 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6461
6462<h5>Arguments:</h5>
6463<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6464 function associated with the unwinding mechanism. The optional
6465 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6466
6467<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6468 or <tt>filter</tt> &mdash; and contains the global variable representing the
6469 "type" that may be caught or filtered respectively. Unlike the
6470 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6471 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6472 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6473 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6474
6475<h5>Semantics:</h5>
6476<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6477 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6478 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6479 calling conventions, how the personality function results are represented in
6480 LLVM IR is target specific.</p>
6481
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6482<p>The clauses are applied in order from top to bottom. If two
6483 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6484 clauses from the calling function are appended to the list of clauses.
6485 When the call stack is being unwound due to an exception being thrown, the
6486 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6487 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6488 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6489
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6490<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6491
6492<ul>
6493 <li>A landing pad block is a basic block which is the unwind destination of an
6494 '<tt>invoke</tt>' instruction.</li>
6495 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6496 first non-PHI instruction.</li>
6497 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6498 pad block.</li>
6499 <li>A basic block that is not a landing pad block may not include a
6500 '<tt>landingpad</tt>' instruction.</li>
6501 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6502 personality function.</li>
6503</ul>
6504
6505<h5>Example:</h5>
6506<pre>
6507 ;; A landing pad which can catch an integer.
6508 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6509 catch i8** @_ZTIi
6510 ;; A landing pad that is a cleanup.
6511 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6512 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6513 ;; A landing pad which can catch an integer and can only throw a double.
6514 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6515 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6516 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6517</pre>
6518
6519</div>
6520
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6521</div>
6522
6523</div>
6524
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6525<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6526<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6527<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6528
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6529<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6530
6531<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6532 well known names and semantics and are required to follow certain
6533 restrictions. Overall, these intrinsics represent an extension mechanism for
6534 the LLVM language that does not require changing all of the transformations
6535 in LLVM when adding to the language (or the bitcode reader/writer, the
6536 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6537
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6538<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6539 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6540 begin with this prefix. Intrinsic functions must always be external
6541 functions: you cannot define the body of intrinsic functions. Intrinsic
6542 functions may only be used in call or invoke instructions: it is illegal to
6543 take the address of an intrinsic function. Additionally, because intrinsic
6544 functions are part of the LLVM language, it is required if any are added that
6545 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6546
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6548 family of functions that perform the same operation but on different data
6549 types. Because LLVM can represent over 8 million different integer types,
6550 overloading is used commonly to allow an intrinsic function to operate on any
6551 integer type. One or more of the argument types or the result type can be
6552 overloaded to accept any integer type. Argument types may also be defined as
6553 exactly matching a previous argument's type or the result type. This allows
6554 an intrinsic function which accepts multiple arguments, but needs all of them
6555 to be of the same type, to only be overloaded with respect to a single
6556 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6557
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6558<p>Overloaded intrinsics will have the names of its overloaded argument types
6559 encoded into its function name, each preceded by a period. Only those types
6560 which are overloaded result in a name suffix. Arguments whose type is matched
6561 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6562 can take an integer of any width and returns an integer of exactly the same
6563 integer width. This leads to a family of functions such as
6564 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6565 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6566 suffix is required. Because the argument's type is matched against the return
6567 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6568
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6569<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6570 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6571
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6572<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6573<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6574 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6575</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6576
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6577<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6578
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579<p>Variable argument support is defined in LLVM with
6580 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6581 intrinsic functions. These functions are related to the similarly named
6582 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6583
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6584<p>All of these functions operate on arguments that use a target-specific value
6585 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6586 not define what this type is, so all transformations should be prepared to
6587 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6588
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6589<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6590 instruction and the variable argument handling intrinsic functions are
6591 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6592
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6593<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6594define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6595 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6596 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6597 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6598 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6599
6600 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6601 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6602
6603 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6604 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6605 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6606 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6607 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6608
6609 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6610 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6611 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6612}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6613
6614declare void @llvm.va_start(i8*)
6615declare void @llvm.va_copy(i8*, i8*)
6616declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6617</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6619<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6620<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6621 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6622</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6623
6624
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6625<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6626
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6627<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6628<pre>
6629 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6630</pre>
6631
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6632<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6633<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6634 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6635
6636<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6637<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6638
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6639<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6640<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641 macro available in C. In a target-dependent way, it initializes
6642 the <tt>va_list</tt> element to which the argument points, so that the next
6643 call to <tt>va_arg</tt> will produce the first variable argument passed to
6644 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6645 need to know the last argument of the function as the compiler can figure
6646 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6648</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6649
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6650<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6651<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6652 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6653</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6654
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6655<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6656
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6657<h5>Syntax:</h5>
6658<pre>
6659 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6660</pre>
6661
6662<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6663<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6664 which has been initialized previously
6665 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6666 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6667
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6668<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6669<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6670
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6671<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6672<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6673 macro available in C. In a target-dependent way, it destroys
6674 the <tt>va_list</tt> element to which the argument points. Calls
6675 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6676 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6677 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6679</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6680
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6681<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6682<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6683 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6684</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6686<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6687
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6688<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6689<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6690 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6691</pre>
6692
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6693<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6694<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6695 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6696
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6697<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6698<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6699 The second argument is a pointer to a <tt>va_list</tt> element to copy
6700 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6701
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6702<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6703<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6704 macro available in C. In a target-dependent way, it copies the
6705 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6706 element. This intrinsic is necessary because
6707 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6708 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6710</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6711
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6712</div>
6713
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6714<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6715<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6716 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6717</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6718
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6719<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6720
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6721<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6722Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6723intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6724roots on the stack</a>, as well as garbage collector implementations that
6725require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6726barriers. Front-ends for type-safe garbage collected languages should generate
6727these intrinsics to make use of the LLVM garbage collectors. For more details,
6728see <a href="GarbageCollection.html">Accurate Garbage Collection with
6729LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6730
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6731<p>The garbage collection intrinsics only operate on objects in the generic
6732 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6733
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6734<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6735<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6736 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6737</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6738
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6739<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6740
6741<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6742<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6743 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6744</pre>
6745
6746<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6747<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6749
6750<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6751<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6752 root pointer. The second pointer (which must be either a constant or a
6753 global value address) contains the meta-data to be associated with the
6754 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6755
6756<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6757<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6758 location. At compile-time, the code generator generates information to allow
6759 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6760 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6761 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6762
6763</div>
6764
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6765<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6766<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6767 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6768</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6769
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6770<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6771
6772<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6773<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6774 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6775</pre>
6776
6777<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6778<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6779 locations, allowing garbage collector implementations that require read
6780 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6781
6782<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6783<p>The second argument is the address to read from, which should be an address
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784 allocated from the garbage collector. The first object is a pointer to the
6785 start of the referenced object, if needed by the language runtime (otherwise
6786 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6787
6788<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6789<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6790 instruction, but may be replaced with substantially more complex code by the
6791 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6792 may only be used in a function which <a href="#gc">specifies a GC
6793 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6794
6795</div>
6796
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6797<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6798<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6799 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6800</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6801
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6802<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6803
6804<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6805<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6806 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6807</pre>
6808
6809<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6810<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6811 locations, allowing garbage collector implementations that require write
6812 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6813
6814<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6815<p>The first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6816 object to store it to, and the third is the address of the field of Obj to
6817 store to. If the runtime does not require a pointer to the object, Obj may
6818 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6819
6820<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6821<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6822 instruction, but may be replaced with substantially more complex code by the
6823 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6824 may only be used in a function which <a href="#gc">specifies a GC
6825 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6826
6827</div>
6828
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6829</div>
6830
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6831<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6832<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6833 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6834</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6835
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6836<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6837
6838<p>These intrinsics are provided by LLVM to expose special features that may
6839 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6840
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6841<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6842<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6843 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6844</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6845
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6846<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6847
6848<h5>Syntax:</h5>
6849<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6850 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6851</pre>
6852
6853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6854<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6855 target-specific value indicating the return address of the current function
6856 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6857
6858<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6859<p>The argument to this intrinsic indicates which function to return the address
6860 for. Zero indicates the calling function, one indicates its caller, etc.
6861 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6862
6863<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6864<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6865 indicating the return address of the specified call frame, or zero if it
6866 cannot be identified. The value returned by this intrinsic is likely to be
6867 incorrect or 0 for arguments other than zero, so it should only be used for
6868 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870<p>Note that calling this intrinsic does not prevent function inlining or other
6871 aggressive transformations, so the value returned may not be that of the
6872 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6873
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6874</div>
6875
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6876<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6877<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6878 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6879</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6880
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6881<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6882
6883<h5>Syntax:</h5>
6884<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6885 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6886</pre>
6887
6888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6889<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6890 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6891
6892<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6893<p>The argument to this intrinsic indicates which function to return the frame
6894 pointer for. Zero indicates the calling function, one indicates its caller,
6895 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6896
6897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6899 indicating the frame address of the specified call frame, or zero if it
6900 cannot be identified. The value returned by this intrinsic is likely to be
6901 incorrect or 0 for arguments other than zero, so it should only be used for
6902 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6904<p>Note that calling this intrinsic does not prevent function inlining or other
6905 aggressive transformations, so the value returned may not be that of the
6906 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6907
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6908</div>
6909
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6910<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6911<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6912 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6913</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6914
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6915<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6916
6917<h5>Syntax:</h5>
6918<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6919 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6920</pre>
6921
6922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6923<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6924 of the function stack, for use
6925 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6926 useful for implementing language features like scoped automatic variable
6927 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6928
6929<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6930<p>This intrinsic returns a opaque pointer value that can be passed
6931 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6932 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6933 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6934 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6935 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6936 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6937
6938</div>
6939
6940<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6941<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6942 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6943</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6945<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6946
6947<h5>Syntax:</h5>
6948<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6949 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6950</pre>
6951
6952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6954 the function stack to the state it was in when the
6955 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6956 executed. This is useful for implementing language features like scoped
6957 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6958
6959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960<p>See the description
6961 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6962
6963</div>
6964
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6965<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6966<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6967 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6968</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6969
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6970<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6971
6972<h5>Syntax:</h5>
6973<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6974 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6975</pre>
6976
6977<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6978<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6979 insert a prefetch instruction if supported; otherwise, it is a noop.
6980 Prefetches have no effect on the behavior of the program but can change its
6981 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6982
6983<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6985 specifier determining if the fetch should be for a read (0) or write (1),
6986 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6987 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6988 specifies whether the prefetch is performed on the data (1) or instruction (0)
6989 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6990 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6991
6992<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993<p>This intrinsic does not modify the behavior of the program. In particular,
6994 prefetches cannot trap and do not produce a value. On targets that support
6995 this intrinsic, the prefetch can provide hints to the processor cache for
6996 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6997
6998</div>
6999
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7000<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7001<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7002 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7003</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7004
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7005<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7006
7007<h5>Syntax:</h5>
7008<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]7009 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7010</pre>
7011
7012<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7013<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
7014 Counter (PC) in a region of code to simulators and other tools. The method
7015 is target specific, but it is expected that the marker will use exported
7016 symbols to transmit the PC of the marker. The marker makes no guarantees
7017 that it will remain with any specific instruction after optimizations. It is
7018 possible that the presence of a marker will inhibit optimizations. The
7019 intended use is to be inserted after optimizations to allow correlations of
7020 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7021
7022<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7023<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7024
7025<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7026<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7027 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7028
7029</div>
7030
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7031<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7032<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7033 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7034</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7035
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7036<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7037
7038<h5>Syntax:</h5>
7039<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7040 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7041</pre>
7042
7043<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7044<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7045 counter register (or similar low latency, high accuracy clocks) on those
7046 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7047 should map to RPCC. As the backing counters overflow quickly (on the order
7048 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7049
7050<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051<p>When directly supported, reading the cycle counter should not modify any
7052 memory. Implementations are allowed to either return a application specific
7053 value or a system wide value. On backends without support, this is lowered
7054 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7055
7056</div>
7057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7058</div>
7059
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7060<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7061<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7062 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7063</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7064
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7065<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066
7067<p>LLVM provides intrinsics for a few important standard C library functions.
7068 These intrinsics allow source-language front-ends to pass information about
7069 the alignment of the pointer arguments to the code generator, providing
7070 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7071
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7072<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7073<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7074 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7075</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7076
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7077<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7078
7079<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]7081 integer bit width and for different address spaces. Not all targets support
7082 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7083
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7084<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7085 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7086 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7087 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7088 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7089</pre>
7090
7091<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7092<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7093 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7094
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7095<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7096 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7097 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7098
7099<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7100
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7101<p>The first argument is a pointer to the destination, the second is a pointer
7102 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7103 number of bytes to copy, the fourth argument is the alignment of the
7104 source and destination locations, and the fifth is a boolean indicating a
7105 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7106
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7107<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108 then the caller guarantees that both the source and destination pointers are
7109 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7110
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7111<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7112 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7113 The detailed access behavior is not very cleanly specified and it is unwise
7114 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7115
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7116<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7117
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7118<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7119 source location to the destination location, which are not allowed to
7120 overlap. It copies "len" bytes of memory over. If the argument is known to
7121 be aligned to some boundary, this can be specified as the fourth argument,
7122 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7123
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7124</div>
7125
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7126<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7127<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7128 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7129</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7131<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7132
7133<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7134<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]7135 width and for different address space. Not all targets support all bit
7136 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7137
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7138<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7139 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7140 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7141 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7142 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7143</pre>
7144
7145<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7146<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7147 source location to the destination location. It is similar to the
7148 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7149 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7151<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7152 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7153 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7154
7155<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7156
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7157<p>The first argument is a pointer to the destination, the second is a pointer
7158 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7159 number of bytes to copy, the fourth argument is the alignment of the
7160 source and destination locations, and the fifth is a boolean indicating a
7161 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7162
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7163<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164 then the caller guarantees that the source and destination pointers are
7165 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7166
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7167<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7168 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7169 The detailed access behavior is not very cleanly specified and it is unwise
7170 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7171
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7172<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7173
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7175 source location to the destination location, which may overlap. It copies
7176 "len" bytes of memory over. If the argument is known to be aligned to some
7177 boundary, this can be specified as the fourth argument, otherwise it should
7178 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7179
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7180</div>
7181
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7182<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7183<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7184 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7185</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7186
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7187<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7188
7189<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7190<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7191 width and for different address spaces. However, not all targets support all
7192 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7194<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7195 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7196 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7197 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7198 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7199</pre>
7200
7201<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7202<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7203 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7204
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7206 intrinsic does not return a value and takes extra alignment/volatile
7207 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7208
7209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7211 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7213 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7214
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7215<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7216 then the caller guarantees that the destination pointer is aligned to that
7217 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7218
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7219<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7220 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7221 The detailed access behavior is not very cleanly specified and it is unwise
7222 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7223
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7224<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7225<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7226 at the destination location. If the argument is known to be aligned to some
7227 boundary, this can be specified as the fourth argument, otherwise it should
7228 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7229
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7230</div>
7231
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7232<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7233<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7234 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7235</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7236
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7237<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7238
7239<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7241 floating point or vector of floating point type. Not all targets support all
7242 types however.</p>
7243
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7244<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7245 declare float @llvm.sqrt.f32(float %Val)
7246 declare double @llvm.sqrt.f64(double %Val)
7247 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7248 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7249 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7250</pre>
7251
7252<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7254 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7255 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7256 behavior for negative numbers other than -0.0 (which allows for better
7257 optimization, because there is no need to worry about errno being
7258 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7259
7260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<p>The argument and return value are floating point numbers of the same
7262 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7263
7264<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265<p>This function returns the sqrt of the specified operand if it is a
7266 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7267
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7268</div>
7269
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7270<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7271<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7272 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7273</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7274
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7275<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7276
7277<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7279 floating point or vector of floating point type. Not all targets support all
7280 types however.</p>
7281
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7282<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7283 declare float @llvm.powi.f32(float %Val, i32 %power)
7284 declare double @llvm.powi.f64(double %Val, i32 %power)
7285 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7286 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7287 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7288</pre>
7289
7290<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7291<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7292 specified (positive or negative) power. The order of evaluation of
7293 multiplications is not defined. When a vector of floating point type is
7294 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7295
7296<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7297<p>The second argument is an integer power, and the first is a value to raise to
7298 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7299
7300<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7301<p>This function returns the first value raised to the second power with an
7302 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7303
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7304</div>
7305
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7306<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7307<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7308 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7309</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7311<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7312
7313<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7314<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7315 floating point or vector of floating point type. Not all targets support all
7316 types however.</p>
7317
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7318<pre>
7319 declare float @llvm.sin.f32(float %Val)
7320 declare double @llvm.sin.f64(double %Val)
7321 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7322 declare fp128 @llvm.sin.f128(fp128 %Val)
7323 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7324</pre>
7325
7326<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7327<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7328
7329<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7330<p>The argument and return value are floating point numbers of the same
7331 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7332
7333<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7334<p>This function returns the sine of the specified operand, returning the same
7335 values as the libm <tt>sin</tt> functions would, and handles error conditions
7336 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7337
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7338</div>
7339
7340<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7341<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7342 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7343</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7344
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7345<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7346
7347<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7349 floating point or vector of floating point type. Not all targets support all
7350 types however.</p>
7351
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7352<pre>
7353 declare float @llvm.cos.f32(float %Val)
7354 declare double @llvm.cos.f64(double %Val)
7355 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7356 declare fp128 @llvm.cos.f128(fp128 %Val)
7357 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7358</pre>
7359
7360<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7361<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7362
7363<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7364<p>The argument and return value are floating point numbers of the same
7365 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7366
7367<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7368<p>This function returns the cosine of the specified operand, returning the same
7369 values as the libm <tt>cos</tt> functions would, and handles error conditions
7370 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7371
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7372</div>
7373
7374<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7375<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7376 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7377</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7378
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7379<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7380
7381<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7382<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7383 floating point or vector of floating point type. Not all targets support all
7384 types however.</p>
7385
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7386<pre>
7387 declare float @llvm.pow.f32(float %Val, float %Power)
7388 declare double @llvm.pow.f64(double %Val, double %Power)
7389 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7390 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7391 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7392</pre>
7393
7394<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7395<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7396 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7397
7398<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7399<p>The second argument is a floating point power, and the first is a value to
7400 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7401
7402<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7403<p>This function returns the first value raised to the second power, returning
7404 the same values as the libm <tt>pow</tt> functions would, and handles error
7405 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7406
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7407</div>
7408
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7409<!-- _______________________________________________________________________ -->
7410<h4>
7411 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7412</h4>
7413
7414<div>
7415
7416<h5>Syntax:</h5>
7417<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7418 floating point or vector of floating point type. Not all targets support all
7419 types however.</p>
7420
7421<pre>
7422 declare float @llvm.exp.f32(float %Val)
7423 declare double @llvm.exp.f64(double %Val)
7424 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7425 declare fp128 @llvm.exp.f128(fp128 %Val)
7426 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7427</pre>
7428
7429<h5>Overview:</h5>
7430<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7431
7432<h5>Arguments:</h5>
7433<p>The argument and return value are floating point numbers of the same
7434 type.</p>
7435
7436<h5>Semantics:</h5>
7437<p>This function returns the same values as the libm <tt>exp</tt> functions
7438 would, and handles error conditions in the same way.</p>
7439
7440</div>
7441
7442<!-- _______________________________________________________________________ -->
7443<h4>
7444 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7445</h4>
7446
7447<div>
7448
7449<h5>Syntax:</h5>
7450<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7451 floating point or vector of floating point type. Not all targets support all
7452 types however.</p>
7453
7454<pre>
7455 declare float @llvm.log.f32(float %Val)
7456 declare double @llvm.log.f64(double %Val)
7457 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7458 declare fp128 @llvm.log.f128(fp128 %Val)
7459 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7460</pre>
7461
7462<h5>Overview:</h5>
7463<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7464
7465<h5>Arguments:</h5>
7466<p>The argument and return value are floating point numbers of the same
7467 type.</p>
7468
7469<h5>Semantics:</h5>
7470<p>This function returns the same values as the libm <tt>log</tt> functions
7471 would, and handles error conditions in the same way.</p>
7472
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7473</div>
7474
7475<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7476<h4>
7477 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7478</h4>
7479
7480<div>
7481
7482<h5>Syntax:</h5>
7483<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7484 floating point or vector of floating point type. Not all targets support all
7485 types however.</p>
7486
7487<pre>
7488 declare float @llvm.fma.f32(float %a, float %b, float %c)
7489 declare double @llvm.fma.f64(double %a, double %b, double %c)
7490 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7491 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7492 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7493</pre>
7494
7495<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7496<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7497 operation.</p>
7498
7499<h5>Arguments:</h5>
7500<p>The argument and return value are floating point numbers of the same
7501 type.</p>
7502
7503<h5>Semantics:</h5>
7504<p>This function returns the same values as the libm <tt>fma</tt> functions
7505 would.</p>
7506
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7507</div>
7508
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7509</div>
7510
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7511<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7512<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7513 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7514</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7515
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7516<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7517
7518<p>LLVM provides intrinsics for a few important bit manipulation operations.
7519 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7520
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7521<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7522<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7523 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7524</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7525
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7526<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7527
7528<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7529<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7530 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7531
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7532<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7533 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7534 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7535 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7536</pre>
7537
7538<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7539<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7540 values with an even number of bytes (positive multiple of 16 bits). These
7541 are useful for performing operations on data that is not in the target's
7542 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7543
7544<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7545<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7546 and low byte of the input i16 swapped. Similarly,
7547 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7548 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7549 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7550 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7551 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7552 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7553
7554</div>
7555
7556<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7557<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7558 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7559</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7560
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7561<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7562
7563<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7564<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7565 width, or on any vector with integer elements. Not all targets support all
7566 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7567
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7568<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7569 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7570 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7571 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7572 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7573 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7574 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7575</pre>
7576
7577<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7578<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7579 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7580
7581<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7582<p>The only argument is the value to be counted. The argument may be of any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7583 integer type, or a vector with integer elements.
7584 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7585
7586<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7587<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7588 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7589
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7590</div>
7591
7592<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7593<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7594 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7595</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7596
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7597<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7598
7599<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7600<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7601 integer bit width, or any vector whose elements are integers. Not all
7602 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7603
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7604<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7605 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7606 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7607 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7608 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7609 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7610 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7611</pre>
7612
7613<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7614<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7615 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7616
7617<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7618<p>The first argument is the value to be counted. This argument may be of any
7619 integer type, or a vectory with integer element type. The return type
7620 must match the first argument type.</p>
7621
7622<p>The second argument must be a constant and is a flag to indicate whether the
7623 intrinsic should ensure that a zero as the first argument produces a defined
7624 result. Historically some architectures did not provide a defined result for
7625 zero values as efficiently, and many algorithms are now predicated on
7626 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7627
7628<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7629<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7630 zeros in a variable, or within each element of the vector.
7631 If <tt>src == 0</tt> then the result is the size in bits of the type of
7632 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7633 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7634
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7635</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7636
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7637<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7638<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7639 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7640</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7641
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7642<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7643
7644<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7645<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7646 integer bit width, or any vector of integer elements. Not all targets
7647 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7648
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7649<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7650 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7651 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7652 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7653 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7654 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7655 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7656</pre>
7657
7658<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7659<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7660 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7661
7662<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7663<p>The first argument is the value to be counted. This argument may be of any
7664 integer type, or a vectory with integer element type. The return type
7665 must match the first argument type.</p>
7666
7667<p>The second argument must be a constant and is a flag to indicate whether the
7668 intrinsic should ensure that a zero as the first argument produces a defined
7669 result. Historically some architectures did not provide a defined result for
7670 zero values as efficiently, and many algorithms are now predicated on
7671 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7672
7673<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7675 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7676 If <tt>src == 0</tt> then the result is the size in bits of the type of
7677 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7678 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7679
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7680</div>
7681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7682</div>
7683
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7684<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7685<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7686 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7687</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7688
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7689<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7690
7691<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7692
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7693<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7694<h4>
7695 <a name="int_sadd_overflow">
7696 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7697 </a>
7698</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7699
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7700<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7701
7702<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7703<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7704 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7705
7706<pre>
7707 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7708 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7709 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7710</pre>
7711
7712<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7713<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7714 a signed addition of the two arguments, and indicate whether an overflow
7715 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7716
7717<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7718<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7719 be of integer types of any bit width, but they must have the same bit
7720 width. The second element of the result structure must be of
7721 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7722 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7723
7724<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7725<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7726 a signed addition of the two variables. They return a structure &mdash; the
7727 first element of which is the signed summation, and the second element of
7728 which is a bit specifying if the signed summation resulted in an
7729 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7730
7731<h5>Examples:</h5>
7732<pre>
7733 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7734 %sum = extractvalue {i32, i1} %res, 0
7735 %obit = extractvalue {i32, i1} %res, 1
7736 br i1 %obit, label %overflow, label %normal
7737</pre>
7738
7739</div>
7740
7741<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7742<h4>
7743 <a name="int_uadd_overflow">
7744 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7745 </a>
7746</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7747
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7748<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7749
7750<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7751<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7752 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7753
7754<pre>
7755 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7756 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7757 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7758</pre>
7759
7760<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7761<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7762 an unsigned addition of the two arguments, and indicate whether a carry
7763 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7764
7765<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7766<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7767 be of integer types of any bit width, but they must have the same bit
7768 width. The second element of the result structure must be of
7769 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7770 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7771
7772<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7773<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7774 an unsigned addition of the two arguments. They return a structure &mdash;
7775 the first element of which is the sum, and the second element of which is a
7776 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7777
7778<h5>Examples:</h5>
7779<pre>
7780 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7781 %sum = extractvalue {i32, i1} %res, 0
7782 %obit = extractvalue {i32, i1} %res, 1
7783 br i1 %obit, label %carry, label %normal
7784</pre>
7785
7786</div>
7787
7788<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7789<h4>
7790 <a name="int_ssub_overflow">
7791 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7792 </a>
7793</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7795<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7796
7797<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7798<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7799 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7800
7801<pre>
7802 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7803 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7804 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7805</pre>
7806
7807<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7808<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7809 a signed subtraction of the two arguments, and indicate whether an overflow
7810 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7811
7812<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7813<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7814 be of integer types of any bit width, but they must have the same bit
7815 width. The second element of the result structure must be of
7816 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7817 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7818
7819<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7820<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7821 a signed subtraction of the two arguments. They return a structure &mdash;
7822 the first element of which is the subtraction, and the second element of
7823 which is a bit specifying if the signed subtraction resulted in an
7824 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7825
7826<h5>Examples:</h5>
7827<pre>
7828 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7829 %sum = extractvalue {i32, i1} %res, 0
7830 %obit = extractvalue {i32, i1} %res, 1
7831 br i1 %obit, label %overflow, label %normal
7832</pre>
7833
7834</div>
7835
7836<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7837<h4>
7838 <a name="int_usub_overflow">
7839 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7840 </a>
7841</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7842
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7843<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7844
7845<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7846<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7847 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7848
7849<pre>
7850 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7851 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7852 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7853</pre>
7854
7855<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7856<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7857 an unsigned subtraction of the two arguments, and indicate whether an
7858 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7859
7860<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7861<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7862 be of integer types of any bit width, but they must have the same bit
7863 width. The second element of the result structure must be of
7864 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7865 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7866
7867<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7868<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7869 an unsigned subtraction of the two arguments. They return a structure &mdash;
7870 the first element of which is the subtraction, and the second element of
7871 which is a bit specifying if the unsigned subtraction resulted in an
7872 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7873
7874<h5>Examples:</h5>
7875<pre>
7876 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7877 %sum = extractvalue {i32, i1} %res, 0
7878 %obit = extractvalue {i32, i1} %res, 1
7879 br i1 %obit, label %overflow, label %normal
7880</pre>
7881
7882</div>
7883
7884<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7885<h4>
7886 <a name="int_smul_overflow">
7887 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7888 </a>
7889</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7890
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7891<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7892
7893<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7894<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7895 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7896
7897<pre>
7898 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7899 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7900 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7901</pre>
7902
7903<h5>Overview:</h5>
7904
7905<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7906 a signed multiplication of the two arguments, and indicate whether an
7907 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7908
7909<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7910<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7911 be of integer types of any bit width, but they must have the same bit
7912 width. The second element of the result structure must be of
7913 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7914 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7915
7916<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7917<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7918 a signed multiplication of the two arguments. They return a structure &mdash;
7919 the first element of which is the multiplication, and the second element of
7920 which is a bit specifying if the signed multiplication resulted in an
7921 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7922
7923<h5>Examples:</h5>
7924<pre>
7925 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7926 %sum = extractvalue {i32, i1} %res, 0
7927 %obit = extractvalue {i32, i1} %res, 1
7928 br i1 %obit, label %overflow, label %normal
7929</pre>
7930
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7931</div>
7932
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7933<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7934<h4>
7935 <a name="int_umul_overflow">
7936 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7937 </a>
7938</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7939
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7940<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7941
7942<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7943<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7944 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7945
7946<pre>
7947 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7948 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7949 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7950</pre>
7951
7952<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7953<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7954 a unsigned multiplication of the two arguments, and indicate whether an
7955 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7956
7957<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7958<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7959 be of integer types of any bit width, but they must have the same bit
7960 width. The second element of the result structure must be of
7961 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7962 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7963
7964<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7965<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7966 an unsigned multiplication of the two arguments. They return a structure
7967 &mdash; the first element of which is the multiplication, and the second
7968 element of which is a bit specifying if the unsigned multiplication resulted
7969 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7970
7971<h5>Examples:</h5>
7972<pre>
7973 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7974 %sum = extractvalue {i32, i1} %res, 0
7975 %obit = extractvalue {i32, i1} %res, 1
7976 br i1 %obit, label %overflow, label %normal
7977</pre>
7978
7979</div>
7980
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7981</div>
7982
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7983<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7984<h3>
Lang Hames5afba6f2012-06-05 19:07:46 +0000[diff] [blame]7985 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
7986</h3>
7987
7988<!-- _______________________________________________________________________ -->
7989
7990<h4>
7991 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
7992</h4>
7993
7994<div>
7995
7996<h5>Syntax:</h5>
7997<pre>
7998 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
7999 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
8000</pre>
8001
8002<h5>Overview:</h5>
8003<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
8004expressions that can be fused if the code generator determines that the fused
8005expression would be legal and efficient.</p>
8006
8007<h5>Arguments:</h5>
8008<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
8009multiplicands, a and b, and an addend c.</p>
8010
8011<h5>Semantics:</h5>
8012<p>The expression:</p>
8013<pre>
8014 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
8015</pre>
8016<p>is equivalent to the expression a * b + c, except that rounding will not be
8017performed between the multiplication and addition steps if the code generator
8018fuses the operations. Fusion is not guaranteed, even if the target platform
8019supports it. If a fused multiply-add is required the corresponding llvm.fma.*
8020intrinsic function should be used instead.</p>
8021
8022<h5>Examples:</h5>
8023<pre>
8024 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
8025</pre>
8026
8027</div>
8028
8029<!-- ======================================================================= -->
8030<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8031 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8032</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8034<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8035
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]8036<p>For most target platforms, half precision floating point is a storage-only
8037 format. This means that it is
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8038 a dense encoding (in memory) but does not support computation in the
8039 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8040
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8041<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8042 value as an i16, then convert it to float with <a
8043 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8044 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8045 double etc). To store the value back to memory, it is first converted to
8046 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8047 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8048 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8049
8050<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8051<h4>
8052 <a name="int_convert_to_fp16">
8053 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8054 </a>
8055</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8056
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8057<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8058
8059<h5>Syntax:</h5>
8060<pre>
8061 declare i16 @llvm.convert.to.fp16(f32 %a)
8062</pre>
8063
8064<h5>Overview:</h5>
8065<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8066 a conversion from single precision floating point format to half precision
8067 floating point format.</p>
8068
8069<h5>Arguments:</h5>
8070<p>The intrinsic function contains single argument - the value to be
8071 converted.</p>
8072
8073<h5>Semantics:</h5>
8074<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8075 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8076 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8077 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8078
8079<h5>Examples:</h5>
8080<pre>
8081 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8082 store i16 %res, i16* @x, align 2
8083</pre>
8084
8085</div>
8086
8087<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8088<h4>
8089 <a name="int_convert_from_fp16">
8090 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8091 </a>
8092</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8093
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8094<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8095
8096<h5>Syntax:</h5>
8097<pre>
8098 declare f32 @llvm.convert.from.fp16(i16 %a)
8099</pre>
8100
8101<h5>Overview:</h5>
8102<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8103 a conversion from half precision floating point format to single precision
8104 floating point format.</p>
8105
8106<h5>Arguments:</h5>
8107<p>The intrinsic function contains single argument - the value to be
8108 converted.</p>
8109
8110<h5>Semantics:</h5>
8111<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8112 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8113 precision floating point format. The input half-float value is represented by
8114 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8115
8116<h5>Examples:</h5>
8117<pre>
8118 %a = load i16* @x, align 2
8119 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8120</pre>
8121
8122</div>
8123
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8124</div>
8125
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8126<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8127<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8128 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8129</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8131<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8133<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8134 prefix), are described in
8135 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8136 Level Debugging</a> document.</p>
8137
8138</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8139
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8140<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8141<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8142 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8143</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8144
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8145<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8146
8147<p>The LLVM exception handling intrinsics (which all start with
8148 <tt>llvm.eh.</tt> prefix), are described in
8149 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8150 Handling</a> document.</p>
8151
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8152</div>
8153
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8154<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8155<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8156 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8157</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8158
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8159<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8160
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8161<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]8162 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8163 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8164 function pointer lacking the nest parameter - the caller does not need to
8165 provide a value for it. Instead, the value to use is stored in advance in a
8166 "trampoline", a block of memory usually allocated on the stack, which also
8167 contains code to splice the nest value into the argument list. This is used
8168 to implement the GCC nested function address extension.</p>
8169
8170<p>For example, if the function is
8171 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8172 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8173 follows:</p>
8174
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]8175<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8176 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8177 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8178 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8179 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8180 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8181</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8182
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8183<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8184 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8185
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8186<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8187<h4>
8188 <a name="int_it">
8189 '<tt>llvm.init.trampoline</tt>' Intrinsic
8190 </a>
8191</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8192
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8193<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8194
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8195<h5>Syntax:</h5>
8196<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8197 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8198</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8199
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8200<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8201<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8202 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8203
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8205<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8206 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8207 sufficiently aligned block of memory; this memory is written to by the
8208 intrinsic. Note that the size and the alignment are target-specific - LLVM
8209 currently provides no portable way of determining them, so a front-end that
8210 generates this intrinsic needs to have some target-specific knowledge.
8211 The <tt>func</tt> argument must hold a function bitcast to
8212 an <tt>i8*</tt>.</p>
8213
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8214<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8215<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8216 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8217 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8218 which can be <a href="#int_trampoline">bitcast (to a new function) and
8219 called</a>. The new function's signature is the same as that of
8220 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8221 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8222 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8223 with the same argument list, but with <tt>nval</tt> used for the missing
8224 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8225 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8226 to the returned function pointer is undefined.</p>
8227</div>
8228
8229<!-- _______________________________________________________________________ -->
8230<h4>
8231 <a name="int_at">
8232 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8233 </a>
8234</h4>
8235
8236<div>
8237
8238<h5>Syntax:</h5>
8239<pre>
8240 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8241</pre>
8242
8243<h5>Overview:</h5>
8244<p>This performs any required machine-specific adjustment to the address of a
8245 trampoline (passed as <tt>tramp</tt>).</p>
8246
8247<h5>Arguments:</h5>
8248<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8249 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8250 </a>.</p>
8251
8252<h5>Semantics:</h5>
8253<p>On some architectures the address of the code to be executed needs to be
8254 different to the address where the trampoline is actually stored. This
8255 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8256 after performing the required machine specific adjustments.
8257 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8258 executed</a>.
8259</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8260
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8261</div>
8262
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8263</div>
8264
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8265<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8266<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8267 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8268</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8269
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8270<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8271
8272<p>This class of intrinsics exists to information about the lifetime of memory
8273 objects and ranges where variables are immutable.</p>
8274
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8275<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8276<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8277 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8278</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8280<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8281
8282<h5>Syntax:</h5>
8283<pre>
8284 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8285</pre>
8286
8287<h5>Overview:</h5>
8288<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8289 object's lifetime.</p>
8290
8291<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 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 Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8295
8296<h5>Semantics:</h5>
8297<p>This intrinsic indicates that before 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
Nick Lewycky8d336592009-10-27 16:56:58 +0000[diff] [blame]8299 never be used and has an undefined value. A load from the pointer that
8300 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8301 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8302
8303</div>
8304
8305<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8306<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8307 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8308</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8309
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8310<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8311
8312<h5>Syntax:</h5>
8313<pre>
8314 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8315</pre>
8316
8317<h5>Overview:</h5>
8318<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8319 object's lifetime.</p>
8320
8321<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8322<p>The first argument is a constant integer representing the size of the
8323 object, or -1 if it is variable sized. The second argument is a pointer to
8324 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8325
8326<h5>Semantics:</h5>
8327<p>This intrinsic indicates that after this point in the code, the value of the
8328 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8329 never be used and has an undefined value. Any stores into the memory object
8330 following this intrinsic may be removed as dead.
8331
8332</div>
8333
8334<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8335<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8336 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8337</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8338
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8339<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8340
8341<h5>Syntax:</h5>
8342<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8343 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8344</pre>
8345
8346<h5>Overview:</h5>
8347<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8348 a memory object will not change.</p>
8349
8350<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8351<p>The first argument is a constant integer representing the size of the
8352 object, or -1 if it is variable sized. The second argument is a pointer to
8353 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8354
8355<h5>Semantics:</h5>
8356<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8357 the return value, the referenced memory location is constant and
8358 unchanging.</p>
8359
8360</div>
8361
8362<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8363<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8364 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8365</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8366
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8367<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8368
8369<h5>Syntax:</h5>
8370<pre>
8371 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8372</pre>
8373
8374<h5>Overview:</h5>
8375<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8376 a memory object are mutable.</p>
8377
8378<h5>Arguments:</h5>
8379<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8380 The second argument is a constant integer representing the size of the
8381 object, or -1 if it is variable sized and the third argument is a pointer
8382 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8383
8384<h5>Semantics:</h5>
8385<p>This intrinsic indicates that the memory is mutable again.</p>
8386
8387</div>
8388
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8389</div>
8390
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8391<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8392<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8393 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8394</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8395
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8396<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8397
8398<p>This class of intrinsics is designed to be generic and has no specific
8399 purpose.</p>
8400
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8401<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8402<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8403 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8404</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8405
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8406<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8407
8408<h5>Syntax:</h5>
8409<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8410 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8411</pre>
8412
8413<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8414<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8415
8416<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8417<p>The first argument is a pointer to a value, the second is a pointer to a
8418 global string, the third is a pointer to a global string which is the source
8419 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8420
8421<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8422<p>This intrinsic allows annotation of local variables with arbitrary strings.
8423 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8424 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8425 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8426
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8427</div>
8428
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8429<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8430<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8431 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8432</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8433
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8434<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8435
8436<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8437<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8438 any integer bit width.</p>
8439
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8440<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8441 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8442 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8443 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8444 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8445 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8446</pre>
8447
8448<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8449<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8450
8451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8452<p>The first argument is an integer value (result of some expression), the
8453 second is a pointer to a global string, the third is a pointer to a global
8454 string which is the source file name, and the last argument is the line
8455 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8456
8457<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8458<p>This intrinsic allows annotations to be put on arbitrary expressions with
8459 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8460 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8461 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8462
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8463</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8464
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8465<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8466<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8467 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8468</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8469
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8470<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8471
8472<h5>Syntax:</h5>
8473<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8474 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8475</pre>
8476
8477<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8478<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8479
8480<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8481<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8482
8483<h5>Semantics:</h5>
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8484<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8485 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8486 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8487
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8488</div>
8489
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8490<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8491<h4>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8492 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8493</h4>
8494
8495<div>
8496
8497<h5>Syntax:</h5>
8498<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8499 declare void @llvm.debugtrap() nounwind
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8500</pre>
8501
8502<h5>Overview:</h5>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8503<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8504
8505<h5>Arguments:</h5>
8506<p>None.</p>
8507
8508<h5>Semantics:</h5>
8509<p>This intrinsic is lowered to code which is intended to cause an execution
8510 trap with the intention of requesting the attention of a debugger.</p>
8511
8512</div>
8513
8514<!-- _______________________________________________________________________ -->
8515<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8516 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8517</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8518
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8519<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8520
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8521<h5>Syntax:</h5>
8522<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8523 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8524</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8525
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8527<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8528 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8529 ensure that it is placed on the stack before local variables.</p>
8530
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8531<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8532<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8533 arguments. The first argument is the value loaded from the stack
8534 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8535 that has enough space to hold the value of the guard.</p>
8536
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8537<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8538<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8539 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8540 stack. This is to ensure that if a local variable on the stack is
8541 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8542 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8543 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8544 function.</p>
8545
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8546</div>
8547
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8548<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8549<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8550 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8551</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8552
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8553<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8554
8555<h5>Syntax:</h5>
8556<pre>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8557 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8558 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8559</pre>
8560
8561<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8562<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8563 the optimizers to determine at compile time whether a) an operation (like
8564 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8565 runtime check for overflow isn't necessary. An object in this context means
8566 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8567
8568<h5>Arguments:</h5>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8569<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8570 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8571 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8572 true) or -1 (if false) when the object size is unknown.
8573 The second argument only accepts constants.</p>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8574
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8575<h5>Semantics:</h5>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8576<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8577 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8578 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8579 (depending on the <tt>min</tt> argument).</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8580
8581</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8582<!-- _______________________________________________________________________ -->
8583<h4>
8584 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8585</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8586
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8587<div>
8588
8589<h5>Syntax:</h5>
8590<pre>
8591 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8592 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8593</pre>
8594
8595<h5>Overview:</h5>
8596<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8597 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8598
8599<h5>Arguments:</h5>
8600<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8601 argument is a value. The second argument is an expected value, this needs to
8602 be a constant value, variables are not allowed.</p>
8603
8604<h5>Semantics:</h5>
8605<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8606</div>
8607
8608</div>
8609
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8610</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8611<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8612<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8613<address>
8614 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8615 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8616 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8617 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8618
8619 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8620 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8621 Last modified: $Date$
8622</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8624</body>
8625</html>