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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 34b3d993e46230b9ba1d1d5dccda89eb09cebe60 / . / 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.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
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>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]54 </ol>
55 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]60 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_floating">Floating Point Types</a></li>
63 <li><a href="#t_void">Void Type</a></li>
64 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </ol>
67 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]70 <li><a href="#t_aggregate">Aggregate Types</a>
71 <ol>
72 <li><a href="#t_array">Array Type</a></li>
73 <li><a href="#t_struct">Structure Type</a></li>
74 <li><a href="#t_pstruct">Packed Structure Type</a></li>
75 <li><a href="#t_union">Union Type</a></li>
76 <li><a href="#t_vector">Vector Type</a></li>
77 </ol>
78 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]79 <li><a href="#t_function">Function Type</a></li>
80 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]87 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
92 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]96 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]104 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
105 <ol>
106 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]107 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
108 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]109 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
110 Global Variable</a></li>
111 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
112 Global Variable</a></li>
113 </ol>
114 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <li><a href="#instref">Instruction Reference</a>
116 <ol>
117 <li><a href="#terminators">Terminator Instructions</a>
118 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]119 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
120 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 </ol>
127 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]136 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
137 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
138 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]139 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
140 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
141 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]146 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
147 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
148 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 </ol>
153 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]154 <li><a href="#vectorops">Vector Operations</a>
155 <ol>
156 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
157 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
158 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]159 </ol>
160 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]161 <li><a href="#aggregateops">Aggregate Operations</a>
162 <ol>
163 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
164 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
165 </ol>
166 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]168 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]170 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
171 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
172 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]173 </ol>
174 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]175 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]176 <ol>
177 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
178 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]182 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
184 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]186 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
187 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]189 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]193 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
194 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]203 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]207 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]210 </ol>
211 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
227 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]237 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]240 </ol>
241 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]245 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]252 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
256 <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]257 <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]258 </ol>
259 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]262 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
263 <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]264 </ol>
265 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]273 <li><a href="#int_atomics">Atomic intrinsics</a>
274 <ol>
275 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
276 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
277 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
278 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
279 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
280 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
281 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
282 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
283 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
284 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
285 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
286 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
287 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
288 </ol>
289 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]290 <li><a href="#int_memorymarkers">Memory Use Markers</a>
291 <ol>
292 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
293 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
294 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
295 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
296 </ol>
297 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]299 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.trap</tt>' Intrinsic</a></li>
306 <li><a href="#int_stackprotector">
307 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]311 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]312 </ol>
313 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]314</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]315
316<div class="doc_author">
317 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
318 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]326
327<p>This document is a reference manual for the LLVM assembly language. LLVM is
328 a Static Single Assignment (SSA) based representation that provides type
329 safety, low-level operations, flexibility, and the capability of representing
330 'all' high-level languages cleanly. It is the common code representation
331 used throughout all phases of the LLVM compilation strategy.</p>
332
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]341<p>The LLVM code representation is designed to be used in three different forms:
342 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
343 for fast loading by a Just-In-Time compiler), and as a human readable
344 assembly language representation. This allows LLVM to provide a powerful
345 intermediate representation for efficient compiler transformations and
346 analysis, while providing a natural means to debug and visualize the
347 transformations. The three different forms of LLVM are all equivalent. This
348 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]349
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]350<p>The LLVM representation aims to be light-weight and low-level while being
351 expressive, typed, and extensible at the same time. It aims to be a
352 "universal IR" of sorts, by being at a low enough level that high-level ideas
353 may be cleanly mapped to it (similar to how microprocessors are "universal
354 IR's", allowing many source languages to be mapped to them). By providing
355 type information, LLVM can be used as the target of optimizations: for
356 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]365<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]367<p>It is important to note that this document describes 'well formed' LLVM
368 assembly language. There is a difference between what the parser accepts and
369 what is considered 'well formed'. For example, the following instruction is
370 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]371
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]376</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]445<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]451</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]455<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]457%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
458%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]459%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]461</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482
483<!-- *********************************************************************** -->
484<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
485<!-- *********************************************************************** -->
486
487<!-- ======================================================================= -->
488<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
489</div>
490
491<div class="doc_text">
492
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]493<p>LLVM programs are composed of "Module"s, each of which is a translation unit
494 of the input programs. Each module consists of functions, global variables,
495 and symbol table entries. Modules may be combined together with the LLVM
496 linker, which merges function (and global variable) definitions, resolves
497 forward declarations, and merges symbol table entries. Here is an example of
498 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]500<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]501<pre>
502<i>; Declare the string constant as a global constant.</i>
503<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504
505<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>
510 <i>; Convert [13 x i8]* to i8 *...</i>
511 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]512
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>
514 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0<br>}
516
517<i>; Named metadata</i>
518!1 = metadata !{i32 41}
519!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]520</pre>
521</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values, where both
530 functions and global variables are global values. Global values are
531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]535</div>
536
537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="linkage">Linkage Types</a>
540</div>
541
542<div class="doc_text">
543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]549 <dd>Global values with private linkage are only directly accessible by objects
550 in the current module. In particular, linking code into a module with an
551 private global value may cause the private to be renamed as necessary to
552 avoid collisions. Because the symbol is private to the module, all
553 references can be updated. This doesn't show up in any symbol table in the
554 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]558 removed by the linker after evaluation. Note that (unlike private
559 symbols) linker_private symbols are subject to coalescing by the linker:
560 weak symbols get merged and redefinitions are rejected. However, unlike
561 normal strong symbols, they are removed by the linker from the final
562 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]565 <dd>Similar to private, but the value shows as a local symbol
566 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
567 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 into the object file corresponding to the LLVM module. They exist to
572 allow inlining and other optimizations to take place given knowledge of
573 the definition of the global, which is known to be somewhere outside the
574 module. Globals with <tt>available_externally</tt> linkage are allowed to
575 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
576 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]580 the same name when linkage occurs. This can be used to implement
581 some forms of inline functions, templates, or other code which must be
582 generated in each translation unit that uses it, but where the body may
583 be overridden with a more definitive definition later. Unreferenced
584 <tt>linkonce</tt> globals are allowed to be discarded. Note that
585 <tt>linkonce</tt> linkage does not actually allow the optimizer to
586 inline the body of this function into callers because it doesn't know if
587 this definition of the function is the definitive definition within the
588 program or whether it will be overridden by a stronger definition.
589 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
590 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]593 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
594 <tt>linkonce</tt> linkage, except that unreferenced globals with
595 <tt>weak</tt> linkage may not be discarded. This is used for globals that
596 are declared "weak" in C source code.</dd>
597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
600 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
601 global scope.
602 Symbols with "<tt>common</tt>" linkage are merged in the same way as
603 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]608
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]612 pointer to array type. When two global variables with appending linkage
613 are linked together, the two global arrays are appended together. This is
614 the LLVM, typesafe, equivalent of having the system linker append together
615 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 <dd>The semantics of this linkage follow the ELF object file model: the symbol
619 is weak until linked, if not linked, the symbol becomes null instead of
620 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
623 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>Some languages allow differing globals to be merged, such as two functions
625 with different semantics. Other languages, such as <tt>C++</tt>, ensure
626 that only equivalent globals are ever merged (the "one definition rule" -
627 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
628 and <tt>weak_odr</tt> linkage types to indicate that the global will only
629 be merged with equivalent globals. These linkage types are otherwise the
630 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]631
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 visible, meaning that it participates in linkage and can be used to
635 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]636</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]638<p>The next two types of linkage are targeted for Microsoft Windows platform
639 only. They are designed to support importing (exporting) symbols from (to)
640 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]645 or variable via a global pointer to a pointer that is set up by the DLL
646 exporting the symbol. On Microsoft Windows targets, the pointer name is
647 formed by combining <code>__imp_</code> and the function or variable
648 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]652 pointer to a pointer in a DLL, so that it can be referenced with the
653 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
654 name is formed by combining <code>__imp_</code> and the function or
655 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]656</dl>
657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
659 another module defined a "<tt>.LC0</tt>" variable and was linked with this
660 one, one of the two would be renamed, preventing a collision. Since
661 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
662 declarations), they are accessible outside of the current module.</p>
663
664<p>It is illegal for a function <i>declaration</i> to have any linkage type
665 other than "externally visible", <tt>dllimport</tt>
666 or <tt>extern_weak</tt>.</p>
667
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]675 <a name="callingconv">Calling Conventions</a>
676</div>
677
678<div class="doc_text">
679
680<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]681 and <a href="#i_invoke">invokes</a> can all have an optional calling
682 convention specified for the call. The calling convention of any pair of
683 dynamic caller/callee must match, or the behavior of the program is
684 undefined. The following calling conventions are supported by LLVM, and more
685 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]690 specified) matches the target C calling conventions. This calling
691 convention supports varargs function calls and tolerates some mismatch in
692 the declared prototype and implemented declaration of the function (as
693 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]697 (e.g. by passing things in registers). This calling convention allows the
698 target to use whatever tricks it wants to produce fast code for the
699 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]702 when this or the GHC convention is used.</a> This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708 as possible under the assumption that the call is not commonly executed.
709 As such, these calls often preserve all registers so that the call does
710 not break any live ranges in the caller side. This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]714 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
715 <dd>This calling convention has been implemented specifically for use by the
716 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
717 It passes everything in registers, going to extremes to achieve this by
718 disabling callee save registers. This calling convention should not be
719 used lightly but only for specific situations such as an alternative to
720 the <em>register pinning</em> performance technique often used when
721 implementing functional programming languages.At the moment only X86
722 supports this convention and it has the following limitations:
723 <ul>
724 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
725 floating point types are supported.</li>
726 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
727 6 floating point parameters.</li>
728 </ul>
729 This calling convention supports
730 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
731 requires both the caller and callee are using it.
732 </dd>
733
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]738</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759 that the declaration is visible to other modules and, in shared libraries,
760 means that the declared entity may be overridden. On Darwin, default
761 visibility means that the declaration is visible to other modules. Default
762 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]766 object if they are in the same shared object. Usually, hidden visibility
767 indicates that the symbol will not be placed into the dynamic symbol
768 table, so no other module (executable or shared library) can reference it
769 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]773 the dynamic symbol table, but that references within the defining module
774 will bind to the local symbol. That is, the symbol cannot be overridden by
775 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]782 <a name="namedtypes">Named Types</a>
783</div>
784
785<div class="doc_text">
786
787<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]788 it easier to read the IR and make the IR more condensed (particularly when
789 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790
791<div class="doc_code">
792<pre>
793%mytype = type { %mytype*, i32 }
794</pre>
795</div>
796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]797<p>You may give a name to any <a href="#typesystem">type</a> except
798 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
799 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802 and that you can therefore specify multiple names for the same type. This
803 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
804 uses structural typing, the name is not part of the type. When printing out
805 LLVM IR, the printer will pick <em>one name</em> to render all types of a
806 particular shape. This means that if you have code where two different
807 source types end up having the same LLVM type, that the dumper will sometimes
808 print the "wrong" or unexpected type. This is an important design point and
809 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]821 instead of run-time. Global variables may optionally be initialized, may
822 have an explicit section to be placed in, and may have an optional explicit
823 alignment specified. A variable may be defined as "thread_local", which
824 means that it will not be shared by threads (each thread will have a
825 separated copy of the variable). A variable may be defined as a global
826 "constant," which indicates that the contents of the variable
827 will <b>never</b> be modified (enabling better optimization, allowing the
828 global data to be placed in the read-only section of an executable, etc).
829 Note that variables that need runtime initialization cannot be marked
830 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]831
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
833 constant, even if the final definition of the global is not. This capability
834 can be used to enable slightly better optimization of the program, but
835 requires the language definition to guarantee that optimizations based on the
836 'constantness' are valid for the translation units that do not include the
837 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]839<p>As SSA values, global variables define pointer values that are in scope
840 (i.e. they dominate) all basic blocks in the program. Global variables
841 always define a pointer to their "content" type because they describe a
842 region of memory, and all memory objects in LLVM are accessed through
843 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>A global variable may be declared to reside in a target-specific numbered
846 address space. For targets that support them, address spaces may affect how
847 optimizations are performed and/or what target instructions are used to
848 access the variable. The default address space is zero. The address space
849 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]850
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]853
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global, which must be a power
855 of 2. If not present, or if the alignment is set to zero, the alignment of
856 the global is set by the target to whatever it feels convenient. If an
857 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]858 alignment. Targets and optimizers are not allowed to over-align the global
859 if the global has an assigned section. In this case, the extra alignment
860 could be observable: for example, code could assume that the globals are
861 densely packed in their section and try to iterate over them as an array,
862 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]864<p>For example, the following defines a global in a numbered address space with
865 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]866
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]867<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]868<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]871</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]872
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]873</div>
874
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
878 <a name="functionstructure">Functions</a>
879</div>
880
881<div class="doc_text">
882
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]884 optional <a href="#linkage">linkage type</a>, an optional
885 <a href="#visibility">visibility style</a>, an optional
886 <a href="#callingconv">calling convention</a>, a return type, an optional
887 <a href="#paramattrs">parameter attribute</a> for the return type, a function
888 name, a (possibly empty) argument list (each with optional
889 <a href="#paramattrs">parameter attributes</a>), optional
890 <a href="#fnattrs">function attributes</a>, an optional section, an optional
891 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
892 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]894<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
895 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>, a return type, an optional
898 <a href="#paramattrs">parameter attribute</a> for the return type, a function
899 name, a possibly empty list of arguments, an optional alignment, and an
900 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]903 (Control Flow Graph) for the function. Each basic block may optionally start
904 with a label (giving the basic block a symbol table entry), contains a list
905 of instructions, and ends with a <a href="#terminators">terminator</a>
906 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]908<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]909 executed on entrance to the function, and it is not allowed to have
910 predecessor basic blocks (i.e. there can not be any branches to the entry
911 block of a function). Because the block can have no predecessors, it also
912 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]917<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]918 the alignment is set to zero, the alignment of the function is set by the
919 target to whatever it feels convenient. If an explicit alignment is
920 specified, the function is forced to have at least that much alignment. All
921 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]949<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]950<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]952</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]953</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]954
955</div>
956
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]958<div class="doc_subsection">
959 <a name="namedmetadatastructure">Named Metadata</a>
960</div>
961
962<div class="doc_text">
963
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
965 nodes</a> (but not metadata strings) and null are the only valid operands for
966 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]967
968<h5>Syntax:</h5>
969<div class="doc_code">
970<pre>
971!1 = metadata !{metadata !"one"}
972!name = !{null, !1}
973</pre>
974</div>
975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1002<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1003 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates to the code generator that the parameter or return value
1010 should be zero-extended to a 32-bit value by the caller (for a parameter)
1011 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be sign-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates that this parameter or return value should be treated in a
1020 special target-dependent fashion during while emitting code for a function
1021 call or return (usually, by putting it in a register as opposed to memory,
1022 though some targets use it to distinguish between two different kinds of
1023 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter should really be passed by value
1027 to the function. The attribute implies that a hidden copy of the pointee
1028 is made between the caller and the callee, so the callee is unable to
1029 modify the value in the callee. This attribute is only valid on LLVM
1030 pointer arguments. It is generally used to pass structs and arrays by
1031 value, but is also valid on pointers to scalars. The copy is considered
1032 to belong to the caller not the callee (for example,
1033 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1034 <tt>byval</tt> parameters). This is not a valid attribute for return
1035 values. The byval attribute also supports specifying an alignment with
1036 the align attribute. This has a target-specific effect on the code
1037 generator that usually indicates a desired alignment for the synthesized
1038 stack slot.</dd>
1039
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates that the pointer parameter specifies the address of a
1042 structure that is the return value of the function in the source program.
1043 This pointer must be guaranteed by the caller to be valid: loads and
1044 stores to the structure may be assumed by the callee to not to trap. This
1045 may only be applied to the first parameter. This is not a valid attribute
1046 for return values. </dd>
1047
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This indicates that the pointer does not alias any global or any other
1050 parameter. The caller is responsible for ensuring that this is the
1051 case. On a function return value, <tt>noalias</tt> additionally indicates
1052 that the pointer does not alias any other pointers visible to the
1053 caller. For further details, please see the discussion of the NoAlias
1054 response in
1055 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1056 analysis</a>.</dd>
1057
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
1081<div class="doc_code">
1082<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088 collector which will cause the compiler to alter its output in order to
1089 support the named garbage collection algorithm.</p>
1090
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are set to communicate additional information about a
1101 function. Function attributes are considered to be part of the function, not
1102 of the function type, so functions with different parameter attributes can
1103 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are simple keywords that follow the type specified. If
1106 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1118 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1119 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1120 the backend should forcibly align the stack pointer. Specify the
1121 desired alignment, which must be a power of two, in parentheses.
1122
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attribute indicates that the inliner should attempt to inline this
1125 function into callers whenever possible, ignoring any active inlining size
1126 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1128 <dt><tt><b>inlinehint</b></tt></dt>
1129 <dd>This attribute indicates that the source code contained a hint that inlining
1130 this function is desirable (such as the "inline" keyword in C/C++). It
1131 is just a hint; it imposes no requirements on the inliner.</dd>
1132
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute suggests that optimization passes and code generator passes
1140 make choices that keep the code size of this function low, and otherwise
1141 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns
1145 normally. This produces undefined behavior at runtime if the function
1146 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns with an
1150 unwind or exceptional control flow. If the function does unwind, its
1151 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the function computes its result (or decides
1155 to unwind an exception) based strictly on its arguments, without
1156 dereferencing any pointer arguments or otherwise accessing any mutable
1157 state (e.g. memory, control registers, etc) visible to caller functions.
1158 It does not write through any pointer arguments
1159 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1160 changes any state visible to callers. This means that it cannot unwind
1161 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1162 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the function does not write through any
1166 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1167 arguments) or otherwise modify any state (e.g. memory, control registers,
1168 etc) visible to caller functions. It may dereference pointer arguments
1169 and read state that may be set in the caller. A readonly function always
1170 returns the same value (or unwinds an exception identically) when called
1171 with the same set of arguments and global state. It cannot unwind an
1172 exception by calling the <tt>C++</tt> exception throwing methods, but may
1173 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function should emit a stack smashing
1177 protector. It is in the form of a "canary"&mdash;a random value placed on
1178 the stack before the local variables that's checked upon return from the
1179 function to see if it has been overwritten. A heuristic is used to
1180 determine if a function needs stack protectors or not.<br>
1181<br>
1182 If a function that has an <tt>ssp</tt> attribute is inlined into a
1183 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1184 function will have an <tt>ssp</tt> attribute.</dd>
1185
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function should <em>always</em> emit a
1188 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1189 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1190<br>
1191 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1192 function that doesn't have an <tt>sspreq</tt> attribute or which has
1193 an <tt>ssp</tt> attribute, then the resulting function will have
1194 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute disables prologue / epilogue emission for the function.
1205 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216
1217<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1218 the GCC "file scope inline asm" blocks. These blocks are internally
1219 concatenated by LLVM and treated as a single unit, but may be separated in
1220 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1221
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1222<div class="doc_code">
1223<pre>
1224module asm "inline asm code goes here"
1225module asm "more can go here"
1226</pre>
1227</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1228
1229<p>The strings can contain any character by escaping non-printable characters.
1230 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]1231 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1233<p>The inline asm code is simply printed to the machine code .s file when
1234 assembly code is generated.</p>
1235
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1236</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1237
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1238<!-- ======================================================================= -->
1239<div class="doc_subsection">
1240 <a name="datalayout">Data Layout</a>
1241</div>
1242
1243<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1246 data is to be laid out in memory. The syntax for the data layout is
1247 simply:</p>
1248
1249<div class="doc_code">
1250<pre>
1251target datalayout = "<i>layout specification</i>"
1252</pre>
1253</div>
1254
1255<p>The <i>layout specification</i> consists of a list of specifications
1256 separated by the minus sign character ('-'). Each specification starts with
1257 a letter and may include other information after the letter to define some
1258 aspect of the data layout. The specifications accepted are as follows:</p>
1259
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1260<dl>
1261 <dt><tt>E</tt></dt>
1262 <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]1263 bits with the most significance have the lowest address location.</dd>
1264
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1271 <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]1272 <i>preferred</i> alignments. All sizes are in bits. Specifying
1273 the <i>pref</i> alignment is optional. If omitted, the
1274 preceding <tt>:</tt> should be omitted too.</dd>
1275
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1277 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1287 (double).</dd>
1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1293 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1296
1297 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1298 <dd>This specifies a set of native integer widths for the target CPU
1299 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1300 "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]1301 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1303</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 specifications in the <tt>datalayout</tt> keyword. The default specifications
1308 are given in this list:</p>
1309
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1312 <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]1313 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1314 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1315 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1316 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1317 <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]1318 alignment of 64-bits</li>
1319 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1320 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1321 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1322 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1323 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1326
1327<p>When LLVM is determining the alignment for a given type, it uses the
1328 following rules:</p>
1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330<ol>
1331 <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]1332 specification is used.</li>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334 <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]1335 smallest integer type that is larger than the bitwidth of the sought type
1336 is used. If none of the specifications are larger than the bitwidth then
1337 the the largest integer type is used. For example, given the default
1338 specifications above, the i7 type will use the alignment of i8 (next
1339 largest) while both i65 and i256 will use the alignment of i64 (largest
1340 specified).</li>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342 <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]1343 largest vector type that is smaller than the sought vector type will be
1344 used as a fall back. This happens because &lt;128 x double&gt; can be
1345 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1348</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1349
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1350<!-- ======================================================================= -->
1351<div class="doc_subsection">
1352 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1353</div>
1354
1355<div class="doc_text">
1356
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1359is undefined. Pointer values are associated with address ranges
1360according to the following rules:</p>
1361
1362<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1363 <li>A pointer value formed from a
1364 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1365 is associated with the addresses associated with the first operand
1366 of the <tt>getelementptr</tt>.</li>
1367 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1368 range of the variable's storage.</li>
1369 <li>The result value of an allocation instruction is associated with
1370 the address range of the allocated storage.</li>
1371 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1372 no address.</li>
1373 <li>A pointer value formed by an
1374 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1375 address ranges of all pointer values that contribute (directly or
1376 indirectly) to the computation of the pointer's value.</li>
1377 <li>The result value of a
1378 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1379 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
1385 </ul>
1386
1387<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1388<tt><a href="#i_load">load</a></tt> merely indicates the size and
1389alignment of the memory from which to load, as well as the
1390interpretation of the value. The first operand of a
1391<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1392and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1393
1394<p>Consequently, type-based alias analysis, aka TBAA, aka
1395<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1396LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1397additional information which specialized optimization passes may use
1398to implement type-based alias analysis.</p>
1399
1400</div>
1401
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1402<!-- ======================================================================= -->
1403<div class="doc_subsection">
1404 <a name="volatile">Volatile Memory Accesses</a>
1405</div>
1406
1407<div class="doc_text">
1408
1409<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1410href="#i_store"><tt>store</tt></a>s, and <a
1411href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1412The optimizers must not change the number of volatile operations or change their
1413order of execution relative to other volatile operations. The optimizers
1414<i>may</i> change the order of volatile operations relative to non-volatile
1415operations. This is not Java's "volatile" and has no cross-thread
1416synchronization behavior.</p>
1417
1418</div>
1419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1420<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1423
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1426<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1427 intermediate representation. Being typed enables a number of optimizations
1428 to be performed on the intermediate representation directly, without having
1429 to do extra analyses on the side before the transformation. A strong type
1430 system makes it easier to read the generated code and enables novel analyses
1431 and transformations that are not feasible to perform on normal three address
1432 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1433
1434</div>
1435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1436<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1446 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1447 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1452 <td><a href="#t_floating">floating point</a></td>
1453 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_integer">integer</a>,
1458 <a href="#t_floating">floating point</a>,
1459 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1466 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1467 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468 <tr>
1469 <td><a href="#t_primitive">primitive</a></td>
1470 <td><a href="#t_label">label</a>,
1471 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1478 <a href="#t_function">function</a>,
1479 <a href="#t_pointer">pointer</a>,
1480 <a href="#t_struct">structure</a>,
1481 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1488</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1490<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1491 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1494</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1496<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1508
1509<div class="doc_text">
1510
1511<h5>Overview:</h5>
1512<p>The integer type is a very simple type that simply specifies an arbitrary
1513 bit width for the integer type desired. Any bit width from 1 bit to
1514 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1515
1516<h5>Syntax:</h5>
1517<pre>
1518 iN
1519</pre>
1520
1521<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1522 value.</p>
1523
1524<h5>Examples:</h5>
1525<table class="layout">
1526 <tr class="layout">
1527 <td class="left"><tt>i1</tt></td>
1528 <td class="left">a single-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i32</tt></td>
1532 <td class="left">a 32-bit integer.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>i1942652</tt></td>
1536 <td class="left">a really big integer of over 1 million bits.</td>
1537 </tr>
1538</table>
1539
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1544
1545<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1546
1547<table>
1548 <tbody>
1549 <tr><th>Type</th><th>Description</th></tr>
1550 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1551 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1552 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1553 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1554 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1555 </tbody>
1556</table>
1557
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1565<h5>Overview:</h5>
1566<p>The void type does not represent any value and has no size.</p>
1567
1568<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1577
1578<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1580<h5>Overview:</h5>
1581<p>The label type represents code labels.</p>
1582
1583<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1590<!-- _______________________________________________________________________ -->
1591<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1596<p>The metadata type represents embedded metadata. No derived types may be
1597 created from metadata except for <a href="#t_function">function</a>
1598 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1611<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1613<p>The real power in LLVM comes from the derived types in the system. This is
1614 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1615 useful types. Each of these types contain one or more element types which
1616 may be a primitive type, or another derived type. For example, it is
1617 possible to have a two dimensional array, using an array as the element type
1618 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1620
1621</div>
1622
1623<!-- _______________________________________________________________________ -->
1624<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1625
1626<div class="doc_text">
1627
1628<p>Aggregate Types are a subset of derived types that can contain multiple
1629 member types. <a href="#t_array">Arrays</a>,
1630 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1631 <a href="#t_union">unions</a> are aggregate types.</p>
1632
1633</div>
1634
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1635</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644 sequentially in memory. The array type requires a size (number of elements)
1645 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1652<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1653 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1658 <td class="left"><tt>[40 x i32]</tt></td>
1659 <td class="left">Array of 40 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[41 x i32]</tt></td>
1663 <td class="left">Array of 41 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[4 x i8]</tt></td>
1667 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1670<p>Here are some examples of multidimensional arrays:</p>
1671<table class="layout">
1672 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1673 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1674 <td class="left">3x4 array of 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1678 <td class="left">12x10 array of single precision floating point values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1682 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1683 </tr>
1684</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1685
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1686<p>There is no restriction on indexing beyond the end of the array implied by
1687 a static type (though there are restrictions on indexing beyond the bounds
1688 of an allocated object in some cases). This means that single-dimension
1689 'variable sized array' addressing can be implemented in LLVM with a zero
1690 length array type. An implementation of 'pascal style arrays' in LLVM could
1691 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1701<p>The function type can be thought of as a function signature. It consists of
1702 a return type and a list of formal parameter types. The return type of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1703 function type is a scalar type, a void type, a struct type, or a union
1704 type. If the return type is a struct type then all struct elements must be
1705 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1712<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]1713 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1714 which indicates that the function takes a variable number of arguments.
1715 Variable argument functions can access their arguments with
1716 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1721<table class="layout">
1722 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1723 <td class="left"><tt>i32 (i32)</tt></td>
1724 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1726 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1728 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1730 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1731 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1735 <td class="left">A vararg function that takes at least one
1736 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1737 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1738 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1742 <td class="left">A function taking an <tt>i32</tt>, returning a
1743 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1745 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756<p>The structure type is used to represent a collection of data members together
1757 in memory. The packing of the field types is defined to match the ABI of the
1758 underlying processor. The elements of a structure may be any type that has a
1759 size.</p>
1760
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1761<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1762 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1763 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1764 Structures in registers are accessed using the
1765 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1766 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773<table class="layout">
1774 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1775 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1776 <td class="left">A triple of three <tt>i32</tt> values</td>
1777 </tr><tr class="layout">
1778 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1779 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1780 second element is a <a href="#t_pointer">pointer</a> to a
1781 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1782 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1791
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1794<h5>Overview:</h5>
1795<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1796 together in memory. There is no padding between fields. Further, the
1797 alignment of a packed structure is 1 byte. The elements of a packed
1798 structure may be any type that has a size.</p>
1799
1800<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1801 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1802 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1803
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1812 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1813 <td class="left">A triple of three <tt>i32</tt> values</td>
1814 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1815 <td class="left">
1816<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1828
1829<div class="doc_text">
1830
1831<h5>Overview:</h5>
1832<p>A union type describes an object with size and alignment suitable for
1833 an object of any one of a given set of types (also known as an "untagged"
1834 union). It is similar in concept and usage to a
1835 <a href="#t_struct">struct</a>, except that all members of the union
1836 have an offset of zero. The elements of a union may be any type that has a
1837 size. Unions must have at least one member - empty unions are not allowed.
1838 </p>
1839
1840<p>The size of the union as a whole will be the size of its largest member,
1841 and the alignment requirements of the union as a whole will be the largest
1842 alignment requirement of any member.</p>
1843
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1844<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1845 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1846 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1847 Since all members are at offset zero, the getelementptr instruction does
1848 not affect the address, only the type of the resulting pointer.</p>
1849
1850<h5>Syntax:</h5>
1851<pre>
1852 union { &lt;type list&gt; }
1853</pre>
1854
1855<h5>Examples:</h5>
1856<table class="layout">
1857 <tr class="layout">
1858 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1859 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1860 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1861 </tr><tr class="layout">
1862 <td class="left">
1863 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1864 <td class="left">A union, where the first element is a <tt>float</tt> and the
1865 second element is a <a href="#t_pointer">pointer</a> to a
1866 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1867 an <tt>i32</tt>.</td>
1868 </tr>
1869</table>
1870
1871</div>
1872
1873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1879<p>The pointer type is used to specify memory locations.
1880 Pointers are commonly used to reference objects in memory.</p>
1881
1882<p>Pointer types may have an optional address space attribute defining the
1883 numbered address space where the pointed-to object resides. The default
1884 address space is number zero. The semantics of non-zero address
1885 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1886
1887<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1888 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1889
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1895<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1896<table class="layout">
1897 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1899 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1900 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1901 </tr>
1902 <tr class="layout">
1903 <td class="left"><tt>i32 (i32 *) *</tt></td>
1904 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1906 <tt>i32</tt>.</td>
1907 </tr>
1908 <tr class="layout">
1909 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1910 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1911 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1913</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1915</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1916
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923<p>A vector type is a simple derived type that represents a vector of elements.
1924 Vector types are used when multiple primitive data are operated in parallel
1925 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1934<p>The number of elements is a constant integer value; elementtype may be any
1935 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1936
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1937<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1940 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1941 <td class="left">Vector of 4 32-bit integer values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1945 <td class="left">Vector of 8 32-bit floating-point values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1949 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1950 </tr>
1951</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1952
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1953</div>
1954
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1955<!-- _______________________________________________________________________ -->
1956<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1957<div class="doc_text">
1958
1959<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 corresponds (for example) to the C notion of a forward declared structure
1962 type. In LLVM, opaque types can eventually be resolved to any type (not just
1963 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1977
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978</div>
1979
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1980<!-- ======================================================================= -->
1981<div class="doc_subsection">
1982 <a name="t_uprefs">Type Up-references</a>
1983</div>
1984
1985<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An "up reference" allows you to refer to a lexically enclosing type without
1989 requiring it to have a name. For instance, a structure declaration may
1990 contain a pointer to any of the types it is lexically a member of. Example
1991 of up references (with their equivalent as named type declarations)
1992 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000<p>An up reference is needed by the asmprinter for printing out cyclic types
2001 when there is no declared name for a type in the cycle. Because the
2002 asmprinter does not want to print out an infinite type string, it needs a
2003 syntax to handle recursive types that have no names (all names are optional
2004 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2011<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
2016 <td class="left"><tt>\1*</tt></td>
2017 <td class="left">Self-referential pointer.</td>
2018 </tr>
2019 <tr class="layout">
2020 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2021 <td class="left">Recursive structure where the upref refers to the out-most
2022 structure.</td>
2023 </tr>
2024</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2027
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2028<!-- *********************************************************************** -->
2029<div class="doc_section"> <a name="constants">Constants</a> </div>
2030<!-- *********************************************************************** -->
2031
2032<div class="doc_text">
2033
2034<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2050 <dd>Standard integers (such as '4') are constants of
2051 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2052 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2056 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2057 notation (see below). The assembler requires the exact decimal value of a
2058 floating-point constant. For example, the assembler accepts 1.25 but
2059 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2060 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2065</dl>
2066
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2067<p>The one non-intuitive notation for constants is the hexadecimal form of
2068 floating point constants. For example, the form '<tt>double
2069 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2070 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2071 constants are required (and the only time that they are generated by the
2072 disassembler) is when a floating point constant must be emitted but it cannot
2073 be represented as a decimal floating point number in a reasonable number of
2074 digits. For example, NaN's, infinities, and other special values are
2075 represented in their IEEE hexadecimal format so that assembly and disassembly
2076 do not cause any bits to change in the constants.</p>
2077
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2079 represented using the 16-digit form shown above (which matches the IEEE754
2080 representation for double); float values must, however, be exactly
2081 representable as IEE754 single precision. Hexadecimal format is always used
2082 for long double, and there are three forms of long double. The 80-bit format
2083 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2084 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2085 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2086 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2087 currently supported target uses this format. Long doubles will only work if
2088 they match the long double format on your target. All hexadecimal formats
2089 are big-endian (sign bit at the left).</p>
2090
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107 type definitions (a comma separated list of elements, surrounded by braces
2108 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2109 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2110 Structure constants must have <a href="#t_struct">structure type</a>, and
2111 the number and types of elements must match those specified by the
2112 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2113
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2114 <dt><b>Union constants</b></dt>
2115 <dd>Union constants are represented with notation similar to a structure with
2116 a single element - that is, a single typed element surrounded
2117 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2118 <a href="#t_union">union type</a> can be initialized with a single-element
2119 struct as long as the type of the struct element matches the type of
2120 one of the union members.</dd>
2121
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2170<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2171<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2175</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2176</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2177
2178</div>
2179
2180<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2184<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]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186 Undefined values may be of any type (other than label or void) and be used
2187 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2190 program is well defined no matter what value is used. This gives the
2191 compiler more freedom to optimize. Here are some examples of (potentially
2192 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2194
2195<div class="doc_code">
2196<pre>
2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
2205</div>
2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
2210<div class="doc_code">
2211<pre>
2212 %A = or %X, undef
2213 %B = and %X, undef
2214Safe:
2215 %A = -1
2216 %B = 0
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220</pre>
2221</div>
2222
2223<p>These logical operations have bits that are not always affected by the input.
2224For example, if "%X" has a zero bit, then the output of the 'and' operation will
2225always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2226such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2227However, it is safe to assume that all bits of the undef could be 0, and
2228optimize the and to 0. Likewise, it is safe to assume that all the bits of
2229the undef operand to the or could be set, allowing the or to be folded to
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2230-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2231
2232<div class="doc_code">
2233<pre>
2234 %A = select undef, %X, %Y
2235 %B = select undef, 42, %Y
2236 %C = select %X, %Y, undef
2237Safe:
2238 %A = %X (or %Y)
2239 %B = 42 (or %Y)
2240 %C = %Y
2241Unsafe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245</pre>
2246</div>
2247
2248<p>This set of examples show that undefined select (and conditional branch)
2249conditions can go "either way" but they have to come from one of the two
2250operands. In the %A example, if %X and %Y were both known to have a clear low
2251bit, then %A would have to have a cleared low bit. However, in the %C example,
2252the optimizer is allowed to assume that the undef operand could be the same as
2253%Y, allowing the whole select to be eliminated.</p>
2254
2255
2256<div class="doc_code">
2257<pre>
2258 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2260 %B = undef
2261 %C = xor %B, %B
2262
2263 %D = undef
2264 %E = icmp lt %D, 4
2265 %F = icmp gte %D, 4
2266
2267Safe:
2268 %A = undef
2269 %B = undef
2270 %C = undef
2271 %D = undef
2272 %E = undef
2273 %F = undef
2274</pre>
2275</div>
2276
2277<p>This example points out that two undef operands are not necessarily the same.
2278This can be surprising to people (and also matches C semantics) where they
2279assume that "X^X" is always zero, even if X is undef. This isn't true for a
2280number of reasons, but the short answer is that an undef "variable" can
2281arbitrarily change its value over its "live range". This is true because the
2282"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2283logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2287
2288<div class="doc_code">
2289<pre>
2290 %A = fdiv undef, %X
2291 %B = fdiv %X, undef
2292Safe:
2293 %A = undef
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples show the crucial difference between an <em>undefined
2299value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2300allowed to have an arbitrary bit-pattern. This means that the %A operation
2301can be constant folded to undef because the undef could be an SNaN, and fdiv is
2302not (currently) defined on SNaN's. However, in the second example, we can make
2303a more aggressive assumption: because the undef is allowed to be an arbitrary
2304value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner8e371aa2009-09-08 19:45:34 +0000[diff] [blame]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2306does not execute at all. This allows us to delete the divide and all code after
2307it: since the undefined operation "can't happen", the optimizer can assume that
2308it occurs in dead code.
2309</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2311<div class="doc_code">
2312<pre>
2313a: store undef -> %X
2314b: store %X -> undef
2315Safe:
2316a: &lt;deleted&gt;
2317b: unreachable
2318</pre>
2319</div>
2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2339<p>There is currently no way of representing a trap value in the IR; they
2340 only exist when produced by instructions such as
2341 <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]2342
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2345<p>
2346<ul>
2347<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2348 their operands.</li>
2349
2350<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2351 to their dynamic predecessor basic block.</li>
2352
2353<li>Function arguments depend on the corresponding actual argument values in
2354 the dynamic callers of their functions.</li>
2355
2356<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2357 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2358 control back to them.</li>
2359
2360<li>Non-volatile loads and stores depend on the most recent stores to all of the
2361 referenced memory addresses, following the order in the IR
2362 (including loads and stores implied by intrinsics such as
2363 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2364
2365<!-- FIXME: padding in the middle of a struct -->
2366
2367<!-- TODO: In the case of multiple threads, this only applies to loads and
2368 stores from the same thread as the store, or which are sequenced after the
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2369 store by synchronization. -->
2370
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2371<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2372
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2373<li>An instruction with externally visible side effects depends on the most
2374 recent preceding instruction with externally visible side effects, following
2375 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2376
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2377<li>An instruction <i>control-depends</i> on a <a href="#i_br"><tt>br</tt></a>,
2378 <a href="#i_switch"><tt>switch</tt></a>, or
2379 <a href="#i_indirectbr"><tt>indirectbr</tt></a> if the <tt>br</tt>,
2380 <tt>switch</tt>, or <tt>indirectbr</tt> has multiple successors and the
2381 instruction is always executed when control transfers to one of the
2382 successors, and may not be executed when control is transfered to
2383 another.</li>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2384
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2385<!-- FIXME: invoke, unwind, exceptions -->
2386
2387<li>Dependence is transitive.</li>
2388
2389</ul>
2390</p>
2391
2392<p>Whenever a trap value is generated, all values which depend on it evaluate
2393 to trap. If they have side effects, the evoke their side effects as if each
2394 operand with a trap value were undef. If they have externally-visible side
2395 effects, the behavior is undefined.</p>
2396
2397<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2398
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2399<div class="doc_code">
2400<pre>
2401entry:
2402 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2403 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2404 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2405 store i32 0, i32* %trap_yet_again ; undefined behavior
2406
2407 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2408 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2409
2410 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2411
2412 %narrowaddr = bitcast i32* @g to i16*
2413 %wideaddr = bitcast i32* @g to i64*
2414 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2415 %trap4 = load i64* %widaddr ; Returns a trap value.
2416
2417 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2418 %br i1 %cmp, %true, %end ; Branch to either destination.
2419
2420true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2421 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2422 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2423 br label %end
2424
2425end:
2426 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2427 ; Both edges into this PHI are
2428 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame^]2429 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2430
2431 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2432 ; so this is defined (ignoring earlier
2433 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2434</pre>
2435</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2436
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2437</div>
2438
2439<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2440<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2441 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2442<div class="doc_text">
2443
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2444<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2445
2446<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2447 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2448 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2449
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2450<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2451 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2452 against null. Pointer equality tests between labels addresses is undefined
2453 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2454 equal to the null pointer. This may also be passed around as an opaque
2455 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2456 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2457 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2458
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2459<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2460 using the value as the operand to an inline assembly, but that is target
2461 specific.
2462 </p>
2463
2464</div>
2465
2466
2467<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2468<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2469</div>
2470
2471<div class="doc_text">
2472
2473<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2474 to be used as constants. Constant expressions may be of
2475 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2476 operation that does not have side effects (e.g. load and call are not
2477 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2478
2479<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2480 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2481 <dd>Truncate a constant to another type. The bit size of CST must be larger
2482 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2483
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2485 <dd>Zero extend a constant to another type. The bit size of CST must be
2486 smaller or equal to the bit size of TYPE. Both types must be
2487 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488
2489 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Sign extend a constant to another type. The bit size of CST must be
2491 smaller or equal to the bit size of TYPE. Both types must be
2492 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
2494 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2495 <dd>Truncate a floating point constant to another floating point type. The
2496 size of CST must be larger than the size of TYPE. Both types must be
2497 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498
2499 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2500 <dd>Floating point extend a constant to another type. The size of CST must be
2501 smaller or equal to the size of TYPE. Both types must be floating
2502 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2503
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2504 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector integer type. CST must be of
2507 scalar or vector floating point type. Both CST and TYPE must be scalars,
2508 or vectors of the same number of elements. If the value won't fit in the
2509 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2510
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2511 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2512 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2513 constant. TYPE must be a scalar or vector integer type. CST must be of
2514 scalar or vector floating point type. Both CST and TYPE must be scalars,
2515 or vectors of the same number of elements. If the value won't fit in the
2516 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2517
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2518 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2519 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520 constant. TYPE must be a scalar or vector floating point type. CST must be
2521 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2522 vectors of the same number of elements. If the value won't fit in the
2523 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2524
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2525 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2526 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527 constant. TYPE must be a scalar or vector floating point type. CST must be
2528 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2529 vectors of the same number of elements. If the value won't fit in the
2530 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2531
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2532 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2533 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2534 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2535 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2536 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2537
2538 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2539 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2540 type. CST must be of integer type. The CST value is zero extended,
2541 truncated, or unchanged to make it fit in a pointer size. This one is
2542 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2543
2544 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2545 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2546 are the same as those for the <a href="#i_bitcast">bitcast
2547 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2548
2549 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2550 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2551 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2553 instruction, the index list may have zero or more indexes, which are
2554 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2555
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2556 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2558
2559 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2560 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2561
2562 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2563 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2564
2565 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2566 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2567 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2568
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2569 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2571 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2572
2573 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2574 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2575 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2576
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2577 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2578 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2579 be any of the <a href="#binaryops">binary</a>
2580 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2581 on operands are the same as those for the corresponding instruction
2582 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2583</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2584
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2585</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2588<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2589<!-- *********************************************************************** -->
2590
2591<!-- ======================================================================= -->
2592<div class="doc_subsection">
2593<a name="inlineasm">Inline Assembler Expressions</a>
2594</div>
2595
2596<div class="doc_text">
2597
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2598<p>LLVM supports inline assembler expressions (as opposed
2599 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2600 a special value. This value represents the inline assembler as a string
2601 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2602 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2603 expression has side effects, and a flag indicating whether the function
2604 containing the asm needs to align its stack conservatively. An example
2605 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2606
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2607<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2608<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2609i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2610</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2611</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2613<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2614 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2615 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2616
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2617<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2618<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2619%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]2620</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2621</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2622
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2623<p>Inline asms with side effects not visible in the constraint list must be
2624 marked as having side effects. This is done through the use of the
2625 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2626
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2627<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2628<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2629call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2630</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2631</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2632
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2633<p>In some cases inline asms will contain code that will not work unless the
2634 stack is aligned in some way, such as calls or SSE instructions on x86,
2635 yet will not contain code that does that alignment within the asm.
2636 The compiler should make conservative assumptions about what the asm might
2637 contain and should generate its usual stack alignment code in the prologue
2638 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2639
2640<div class="doc_code">
2641<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2642call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2643</pre>
2644</div>
2645
2646<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2647 first.</p>
2648
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2649<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2650 documented here. Constraints on what can be done (e.g. duplication, moving,
2651 etc need to be documented). This is probably best done by reference to
2652 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2653</div>
2654
2655<div class="doc_subsubsection">
2656<a name="inlineasm_md">Inline Asm Metadata</a>
2657</div>
2658
2659<div class="doc_text">
2660
2661<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2662 attached to it that contains a constant integer. If present, the code
2663 generator will use the integer as the location cookie value when report
2664 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2665 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2666 source code that produced it. For example:</p>
2667
2668<div class="doc_code">
2669<pre>
2670call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2671...
2672!42 = !{ i32 1234567 }
2673</pre>
2674</div>
2675
2676<p>It is up to the front-end to make sense of the magic numbers it places in the
2677 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2678
2679</div>
2680
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2681<!-- ======================================================================= -->
2682<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2683 Strings</a>
2684</div>
2685
2686<div class="doc_text">
2687
2688<p>LLVM IR allows metadata to be attached to instructions in the program that
2689 can convey extra information about the code to the optimizers and code
2690 generator. One example application of metadata is source-level debug
2691 information. There are two metadata primitives: strings and nodes. All
2692 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2693 preceding exclamation point ('<tt>!</tt>').</p>
2694
2695<p>A metadata string is a string surrounded by double quotes. It can contain
2696 any character by escaping non-printable characters with "\xx" where "xx" is
2697 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2698
2699<p>Metadata nodes are represented with notation similar to structure constants
2700 (a comma separated list of elements, surrounded by braces and preceded by an
2701 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2702 10}</tt>". Metadata nodes can have any values as their operand.</p>
2703
2704<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2705 metadata nodes, which can be looked up in the module symbol table. For
2706 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2707
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2708<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2709 function is using two metadata arguments.
2710
2711 <div class="doc_code">
2712 <pre>
2713 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2714 </pre>
2715 </div></p>
2716
2717<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2718 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2719
2720 <div class="doc_code">
2721 <pre>
2722 %indvar.next = add i64 %indvar, 1, !dbg !21
2723 </pre>
2724 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2725</div>
2726
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2727
2728<!-- *********************************************************************** -->
2729<div class="doc_section">
2730 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2731</div>
2732<!-- *********************************************************************** -->
2733
2734<p>LLVM has a number of "magic" global variables that contain data that affect
2735code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2736of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2737section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2738by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2739
2740<!-- ======================================================================= -->
2741<div class="doc_subsection">
2742<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2743</div>
2744
2745<div class="doc_text">
2746
2747<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2748href="#linkage_appending">appending linkage</a>. This array contains a list of
2749pointers to global variables and functions which may optionally have a pointer
2750cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2751
2752<pre>
2753 @X = global i8 4
2754 @Y = global i32 123
2755
2756 @llvm.used = appending global [2 x i8*] [
2757 i8* @X,
2758 i8* bitcast (i32* @Y to i8*)
2759 ], section "llvm.metadata"
2760</pre>
2761
2762<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2763compiler, assembler, and linker are required to treat the symbol as if there is
2764a reference to the global that it cannot see. For example, if a variable has
2765internal linkage and no references other than that from the <tt>@llvm.used</tt>
2766list, it cannot be deleted. This is commonly used to represent references from
2767inline asms and other things the compiler cannot "see", and corresponds to
2768"attribute((used))" in GNU C.</p>
2769
2770<p>On some targets, the code generator must emit a directive to the assembler or
2771object file to prevent the assembler and linker from molesting the symbol.</p>
2772
2773</div>
2774
2775<!-- ======================================================================= -->
2776<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2777<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2778</div>
2779
2780<div class="doc_text">
2781
2782<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2783<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2784touching the symbol. On targets that support it, this allows an intelligent
2785linker to optimize references to the symbol without being impeded as it would be
2786by <tt>@llvm.used</tt>.</p>
2787
2788<p>This is a rare construct that should only be used in rare circumstances, and
2789should not be exposed to source languages.</p>
2790
2791</div>
2792
2793<!-- ======================================================================= -->
2794<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2795<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2796</div>
2797
2798<div class="doc_text">
2799
2800<p>TODO: Describe this.</p>
2801
2802</div>
2803
2804<!-- ======================================================================= -->
2805<div class="doc_subsection">
2806<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2807</div>
2808
2809<div class="doc_text">
2810
2811<p>TODO: Describe this.</p>
2812
2813</div>
2814
2815
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2816<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2817<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2818<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2820<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2821
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822<p>The LLVM instruction set consists of several different classifications of
2823 instructions: <a href="#terminators">terminator
2824 instructions</a>, <a href="#binaryops">binary instructions</a>,
2825 <a href="#bitwiseops">bitwise binary instructions</a>,
2826 <a href="#memoryops">memory instructions</a>, and
2827 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2832<div class="doc_subsection"> <a name="terminators">Terminator
2833Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2834
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2838 in a program ends with a "Terminator" instruction, which indicates which
2839 block should be executed after the current block is finished. These
2840 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2841 control flow, not values (the one exception being the
2842 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2843
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2844<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2845 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2846 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2847 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2848 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2849 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2850 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2851 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2852
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2853</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2854
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2856<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2857Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2859<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2862<pre>
2863 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]2864 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2866
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2869 a value) from a function back to the caller.</p>
2870
2871<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2872 value and then causes control flow, and one that just causes control flow to
2873 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2877 return value. The type of the return value must be a
2878 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2881 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2882 value or a return value with a type that does not match its type, or if it
2883 has a void return type and contains a '<tt>ret</tt>' instruction with a
2884 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2888 the calling function's context. If the caller is a
2889 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2890 instruction after the call. If the caller was an
2891 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2892 the beginning of the "normal" destination block. If the instruction returns
2893 a value, that value shall set the call or invoke instruction's return
2894 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2897<pre>
2898 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2899 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2900 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]2901</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2902
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2905<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2909<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2910<pre>
2911 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2916 different basic block in the current function. There are two forms of this
2917 instruction, corresponding to a conditional branch and an unconditional
2918 branch.</p>
2919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2922 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2923 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2924 target.</p>
2925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2927<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2928 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2929 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2930 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2932<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2933<pre>
2934Test:
2935 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2936 br i1 %cond, label %IfEqual, label %IfUnequal
2937IfEqual:
2938 <a href="#i_ret">ret</a> i32 1
2939IfUnequal:
2940 <a href="#i_ret">ret</a> i32 0
2941</pre>
2942
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2943</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2946<div class="doc_subsubsection">
2947 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2948</div>
2949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2950<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2953<pre>
2954 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2955</pre>
2956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2958<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]2959 several different places. It is a generalization of the '<tt>br</tt>'
2960 instruction, allowing a branch to occur to one of many possible
2961 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2964<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2966 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2967 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2969<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2970<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2971 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2972 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2973 transferred to the corresponding destination; otherwise, control flow is
2974 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2975
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2976<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2978 <tt>switch</tt> instruction, this instruction may be code generated in
2979 different ways. For example, it could be generated as a series of chained
2980 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2981
2982<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2983<pre>
2984 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2985 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2987
2988 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2989 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990
2991 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2992 switch i32 %val, label %otherwise [ i32 0, label %onzero
2993 i32 1, label %onone
2994 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2997</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2998
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3002 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3003</div>
3004
3005<div class="doc_text">
3006
3007<h5>Syntax:</h5>
3008<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3009 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]3010</pre>
3011
3012<h5>Overview:</h5>
3013
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3014<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3015 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3016 "<tt>address</tt>". Address must be derived from a <a
3017 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3018
3019<h5>Arguments:</h5>
3020
3021<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3022 rest of the arguments indicate the full set of possible destinations that the
3023 address may point to. Blocks are allowed to occur multiple times in the
3024 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3025
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3026<p>This destination list is required so that dataflow analysis has an accurate
3027 understanding of the CFG.</p>
3028
3029<h5>Semantics:</h5>
3030
3031<p>Control transfers to the block specified in the address argument. All
3032 possible destination blocks must be listed in the label list, otherwise this
3033 instruction has undefined behavior. This implies that jumps to labels
3034 defined in other functions have undefined behavior as well.</p>
3035
3036<h5>Implementation:</h5>
3037
3038<p>This is typically implemented with a jump through a register.</p>
3039
3040<h5>Example:</h5>
3041<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3042 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3043</pre>
3044
3045</div>
3046
3047
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3048<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049<div class="doc_subsubsection">
3050 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3051</div>
3052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3053<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3054
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3055<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3056<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3057 &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]3058 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3059</pre>
3060
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3061<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3062<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063 function, with the possibility of control flow transfer to either the
3064 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3065 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3066 control flow will return to the "normal" label. If the callee (or any
3067 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3068 instruction, control is interrupted and continued at the dynamically nearest
3069 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3072<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3074<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3076 convention</a> the call should use. If none is specified, the call
3077 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3078
3079 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3080 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3081 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3082
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3083 <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]3084 function value being invoked. In most cases, this is a direct function
3085 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3086 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3087
3088 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3092 signature argument types and parameter attributes. All arguments must be
3093 of <a href="#t_firstclass">first class</a> type. If the function
3094 signature indicates the function accepts a variable number of arguments,
3095 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3102
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3103 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3105 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3106</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<p>This instruction is designed to operate as a standard
3110 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3111 primary difference is that it establishes an association with a label, which
3112 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3113
3114<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3116 exception. Additionally, this is important for implementation of
3117 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3118
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3119<p>For the purposes of the SSA form, the definition of the value returned by the
3120 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3121 block to the "normal" label. If the callee unwinds then no return value is
3122 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3123
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3124<p>Note that the code generator does not yet completely support unwind, and
3125that the invoke/unwind semantics are likely to change in future versions.</p>
3126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3127<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3128<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3129 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3130 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3131 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3132 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3133</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3136
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3138
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3139<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3140Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3141
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3142<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3143
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3144<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3145<pre>
3146 unwind
3147</pre>
3148
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151 at the first callee in the dynamic call stack which used
3152 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3153 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3155<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3156<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157 immediately halt. The dynamic call stack is then searched for the
3158 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3159 Once found, execution continues at the "exceptional" destination block
3160 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3161 instruction in the dynamic call chain, undefined behavior results.</p>
3162
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3163<p>Note that the code generator does not yet completely support unwind, and
3164that the invoke/unwind semantics are likely to change in future versions.</p>
3165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3166</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3167
3168<!-- _______________________________________________________________________ -->
3169
3170<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3171Instruction</a> </div>
3172
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 unreachable
3178</pre>
3179
3180<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182 instruction is used to inform the optimizer that a particular portion of the
3183 code is not reachable. This can be used to indicate that the code after a
3184 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3185
3186<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3187<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3188
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3189</div>
3190
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3191<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3192<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3193
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3194<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195
3196<p>Binary operators are used to do most of the computation in a program. They
3197 require two operands of the same type, execute an operation on them, and
3198 produce a single value. The operands might represent multiple data, as is
3199 the case with the <a href="#t_vector">vector</a> data type. The result value
3200 has the same type as its operands.</p>
3201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3202<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3204</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3206<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3207<div class="doc_subsubsection">
3208 <a name="i_add">'<tt>add</tt>' Instruction</a>
3209</div>
3210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3211<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3213<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3215 &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]3216 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3217 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3218 &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]3219</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3222<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3223
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3224<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3225<p>The two arguments to the '<tt>add</tt>' instruction must
3226 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3227 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3228
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3229<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3230<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3231
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232<p>If the sum has unsigned overflow, the result returned is the mathematical
3233 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]3234
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235<p>Because LLVM integers use a two's complement representation, this instruction
3236 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3237
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3238<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3239 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3240 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3241 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3242 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3247</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3249</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3252<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3253 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3261</pre>
3262
3263<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3264<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3265
3266<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3267<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3269 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3272<p>The value produced is the floating point sum of the two operands.</p>
3273
3274<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3275<pre>
3276 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3277</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<!-- _______________________________________________________________________ -->
3282<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3284</div>
3285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3286<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3288<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3290 &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]3291 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3292 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3293 &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]3294</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3297<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3298 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3299
3300<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3301 '<tt>neg</tt>' instruction present in most other intermediate
3302 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3304<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305<p>The two arguments to the '<tt>sub</tt>' instruction must
3306 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3307 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3309<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3310<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3311
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3312<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3313 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3314 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3315
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316<p>Because LLVM integers use a two's complement representation, this instruction
3317 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3319<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3320 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3321 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3322 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3323 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3328 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3329</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3331</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3333<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3334<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3335 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3336</div>
3337
3338<div class="doc_text">
3339
3340<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3341<pre>
3342 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3343</pre>
3344
3345<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3346<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3348
3349<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350 '<tt>fneg</tt>' instruction present in most other intermediate
3351 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3352
3353<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3354<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3356 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the floating point difference of the two operands.</p>
3360
3361<h5>Example:</h5>
3362<pre>
3363 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3364 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3365</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3366
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3367</div>
3368
3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3371 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3372</div>
3373
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3374<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3378 &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]3379 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3380 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3381 &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]3382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388<p>The two arguments to the '<tt>mul</tt>' instruction must
3389 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3390 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3392<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3393<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395<p>If the result of the multiplication has unsigned overflow, the result
3396 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3397 width of the result.</p>
3398
3399<p>Because LLVM integers use a two's complement representation, and the result
3400 is the same width as the operands, this instruction returns the correct
3401 result for both signed and unsigned integers. If a full product
3402 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3403 be sign-extended or zero-extended as appropriate to the width of the full
3404 product.</p>
3405
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3406<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3407 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3408 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3409 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3410 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3415</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3416
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3417</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3420<div class="doc_subsubsection">
3421 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3422</div>
3423
3424<div class="doc_text">
3425
3426<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &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]3429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3431<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3433
3434<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3435<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3437 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3438
3439<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3440<p>The value produced is the floating point product of the two operands.</p>
3441
3442<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &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]3445</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3447</div>
3448
3449<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3451</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456<pre>
3457 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3459
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3464<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3466 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3467
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3469<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3471<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3473
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3474<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3479</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3481</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3485</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3491 &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]3492 &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]3493</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3497
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3499<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3501 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504<p>The value produced is the signed integer quotient of the two operands rounded
3505 towards zero.</p>
3506
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3507<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3509
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3510<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511 undefined behavior; this is a rare case, but can occur, for example, by doing
3512 a 32-bit division of -2147483648 by -1.</p>
3513
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3514<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3515 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3516 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3517
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3521</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3523</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3527Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3529<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3532<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3533 &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]3534</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536<h5>Overview:</h5>
3537<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3538
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3540<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3542 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3545<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548<pre>
3549 &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]3550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3552</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3554<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3555<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3556</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3558<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &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]3563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3565<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3567 division of its two arguments.</p>
3568
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3570<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3572 values. Both arguments must have identical types.</p>
3573
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576 This instruction always performs an unsigned division to get the
3577 remainder.</p>
3578
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3579<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3581
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3582<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3584<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585<pre>
3586 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3587</pre>
3588
3589</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3594</div>
3595
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3600 &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]3601</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3605 division of its two operands. This instruction can also take
3606 <a href="#t_vector">vector</a> versions of the values in which case the
3607 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3608
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3609<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3610<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3612 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3613
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3614<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3615<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3617 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3618 a value. For more information about the difference,
3619 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3620 Math Forum</a>. For a table of how this is implemented in various languages,
3621 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3622 Wikipedia: modulo operation</a>.</p>
3623
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3624<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3626
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3627<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3628 Overflow also leads to undefined behavior; this is a rare case, but can
3629 occur, for example, by taking the remainder of a 32-bit division of
3630 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3631 lets srem be implemented using instructions that return both the result of
3632 the division and the remainder.)</p>
3633
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3634<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3637</pre>
3638
3639</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3641<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3642<div class="doc_subsubsection">
3643 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3644
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3646
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3647<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648<pre>
3649 &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]3650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3654 its two operands.</p>
3655
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Arguments:</h5>
3657<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3658 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3659 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3660
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<p>This instruction returns the <i>remainder</i> of a division. The remainder
3663 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
3667 &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]3668</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3669
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3670</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3671
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3672<!-- ======================================================================= -->
3673<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3674Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3675
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3676<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677
3678<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3679 program. They are generally very efficient instructions and can commonly be
3680 strength reduced from other instructions. They require two operands of the
3681 same type, execute an operation on them, and produce a single value. The
3682 resulting value is the same type as its operands.</p>
3683
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3684</div>
3685
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3686<!-- _______________________________________________________________________ -->
3687<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3688Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3690<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3692<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693<pre>
3694 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3696
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3697<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3699 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3703 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3704 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3705
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3708 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3709 is (statically or dynamically) negative or equal to or larger than the number
3710 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3711 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3712 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<h5>Example:</h5>
3715<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3717 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3718 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3719 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3720 &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]3721</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3723</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3727Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3729<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3730
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3731<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3738 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3741<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3743 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3744
3745<h5>Semantics:</h5>
3746<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3747 significant bits of the result will be filled with zero bits after the shift.
3748 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3749 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3750 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3751 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Example:</h5>
3754<pre>
3755 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3756 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3757 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3758 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3759 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3760 &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]3761</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3763</div>
3764
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3765<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3766<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3767Instruction</a> </div>
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3773</pre>
3774
3775<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3777 operand shifted to the right a specified number of bits with sign
3778 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3781<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786<p>This instruction always performs an arithmetic shift right operation, The
3787 most significant bits of the result will be filled with the sign bit
3788 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3789 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3790 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3791 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3792
3793<h5>Example:</h5>
3794<pre>
3795 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3796 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3797 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3798 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3799 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3800 &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]3801</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3803</div>
3804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3805<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3806<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3807Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3808
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3809<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3811<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3812<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3813 &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]3814</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3815
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3818 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3821<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3822 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3823 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3826<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3828<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3829 <tbody>
3830 <tr>
3831 <td>In0</td>
3832 <td>In1</td>
3833 <td>Out</td>
3834 </tr>
3835 <tr>
3836 <td>0</td>
3837 <td>0</td>
3838 <td>0</td>
3839 </tr>
3840 <tr>
3841 <td>0</td>
3842 <td>1</td>
3843 <td>0</td>
3844 </tr>
3845 <tr>
3846 <td>1</td>
3847 <td>0</td>
3848 <td>0</td>
3849 </tr>
3850 <tr>
3851 <td>1</td>
3852 <td>1</td>
3853 <td>1</td>
3854 </tr>
3855 </tbody>
3856</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3859<pre>
3860 &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]3861 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3862 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3863</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3864</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3865<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3866<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871<pre>
3872 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3873</pre>
3874
3875<h5>Overview:</h5>
3876<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3877 two operands.</p>
3878
3879<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3880<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3881 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3882 values. Both arguments must have identical types.</p>
3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3885<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3886
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3887<table border="1" cellspacing="0" cellpadding="4">
3888 <tbody>
3889 <tr>
3890 <td>In0</td>
3891 <td>In1</td>
3892 <td>Out</td>
3893 </tr>
3894 <tr>
3895 <td>0</td>
3896 <td>0</td>
3897 <td>0</td>
3898 </tr>
3899 <tr>
3900 <td>0</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 <tr>
3905 <td>1</td>
3906 <td>0</td>
3907 <td>1</td>
3908 </tr>
3909 <tr>
3910 <td>1</td>
3911 <td>1</td>
3912 <td>1</td>
3913 </tr>
3914 </tbody>
3915</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918<pre>
3919 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3920 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3921 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3922</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3924</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3927<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3928Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3929
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3930<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3932<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933<pre>
3934 &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]3935</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3939 its two operands. The <tt>xor</tt> is used to implement the "one's
3940 complement" operation, which is the "~" operator in C.</p>
3941
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3943<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3945 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3948<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3950<table border="1" cellspacing="0" cellpadding="4">
3951 <tbody>
3952 <tr>
3953 <td>In0</td>
3954 <td>In1</td>
3955 <td>Out</td>
3956 </tr>
3957 <tr>
3958 <td>0</td>
3959 <td>0</td>
3960 <td>0</td>
3961 </tr>
3962 <tr>
3963 <td>0</td>
3964 <td>1</td>
3965 <td>1</td>
3966 </tr>
3967 <tr>
3968 <td>1</td>
3969 <td>0</td>
3970 <td>1</td>
3971 </tr>
3972 <tr>
3973 <td>1</td>
3974 <td>1</td>
3975 <td>0</td>
3976 </tr>
3977 </tbody>
3978</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3980<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3983 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3984 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3985 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3986</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3988</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3990<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3991<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3992 <a name="vectorops">Vector Operations</a>
3993</div>
3994
3995<div class="doc_text">
3996
3997<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998 target-independent manner. These instructions cover the element-access and
3999 vector-specific operations needed to process vectors effectively. While LLVM
4000 does directly support these vector operations, many sophisticated algorithms
4001 will want to use target-specific intrinsics to take full advantage of a
4002 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4003
4004</div>
4005
4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection">
4008 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4009</div>
4010
4011<div class="doc_text">
4012
4013<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4014<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4015 &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]4016</pre>
4017
4018<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4020 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4021
4022
4023<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4025 of <a href="#t_vector">vector</a> type. The second operand is an index
4026 indicating the position from which to extract the element. The index may be
4027 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The result is a scalar of the same type as the element type of
4031 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4032 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4033 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4037 &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]4038</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4039
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
4044 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4050<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4051 &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]4052</pre>
4053
4054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4056 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4060 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4061 whose type must equal the element type of the first operand. The third
4062 operand is an index indicating the position at which to insert the value.
4063 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4067 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4068 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4069 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4072<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4073 &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]4074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4086<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4087 &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]4088</pre>
4089
4090<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4092 from two input vectors, returning a vector with the same element type as the
4093 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4097 with types that match each other. The third argument is a shuffle mask whose
4098 element type is always 'i32'. The result of the instruction is a vector
4099 whose length is the same as the shuffle mask and whose element type is the
4100 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4101
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4102<p>The shuffle mask operand is required to be a constant vector with either
4103 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4104
4105<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106<p>The elements of the two input vectors are numbered from left to right across
4107 both of the vectors. The shuffle mask operand specifies, for each element of
4108 the result vector, which element of the two input vectors the result element
4109 gets. The element selector may be undef (meaning "don't care") and the
4110 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4111
4112<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4114 &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]4115 &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]4116 &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]4117 &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]4118 &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]4119 &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]4120 &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]4121 &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]4122</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4125
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4126<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4127<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4128 <a name="aggregateops">Aggregate Operations</a>
4129</div>
4130
4131<div class="doc_text">
4132
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4133<p>LLVM supports several instructions for working with
4134 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135
4136</div>
4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4141</div>
4142
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4146<pre>
4147 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4151<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4152 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4156 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4157 <a href="#t_array">array</a> type. The operands are constant indices to
4158 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4162<p>The result is the value at the position in the aggregate specified by the
4163 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4166<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4167 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4168</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4169
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection">
4174 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4175</div>
4176
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4180<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4181 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4182</pre>
4183
4184<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4185<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4186 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4187
4188<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4190 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4191 <a href="#t_array">array</a> type. The second operand is a first-class
4192 value to insert. The following operands are constant indices indicating
4193 the position at which to insert the value in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4195 value to insert must have the same type as the value identified by the
4196 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4200 that of <tt>val</tt> except that the value at the position specified by the
4201 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4202
4203<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4204<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4205 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4206 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4207</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4209</div>
4210
4211
4212<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4213<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4214 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4215</div>
4216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4217<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4218
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219<p>A key design point of an SSA-based representation is how it represents
4220 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4221 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4224</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4226<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4227<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4228 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4229</div>
4230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4231<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4234<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4235 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4236</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4238<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4239<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240 currently executing function, to be automatically released when this function
4241 returns to its caller. The object is always allocated in the generic address
4242 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>alloca</tt>' instruction
4246 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4247 runtime stack, returning a pointer of the appropriate type to the program.
4248 If "NumElements" is specified, it is the number of elements allocated,
4249 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4250 specified, the value result of the allocation is guaranteed to be aligned to
4251 at least that boundary. If not specified, or if zero, the target can choose
4252 to align the allocation on any convenient boundary compatible with the
4253 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4255<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4257<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4258<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4260 memory is automatically released when the function returns. The
4261 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4262 variables that must have an address available. When the function returns
4263 (either with the <tt><a href="#i_ret">ret</a></tt>
4264 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4265 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4267<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4268<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4269 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4270 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4271 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4272 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4273</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4277<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4278<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4279Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4280
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4281<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4285 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4286 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4287 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288</pre>
4289
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4291<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4295 from which to load. The pointer must point to
4296 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4297 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4298 number or order of execution of this <tt>load</tt> with other <a
4299 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4301<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302 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]4303 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304 alignment for the target. It is the responsibility of the code emitter to
4305 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4306 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307 produce less efficient code. An alignment of 1 is always safe.</p>
4308
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4309<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4310 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4311 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4312 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4313 and code generator that this load is not expected to be reused in the cache.
4314 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4315 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4316
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318<p>The location of memory pointed to is loaded. If the value being loaded is of
4319 scalar type then the number of bytes read does not exceed the minimum number
4320 of bytes needed to hold all bits of the type. For example, loading an
4321 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4322 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4323 is undefined if the value was not originally written using a store of the
4324 same type.</p>
4325
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327<pre>
4328 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4329 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4330 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4331</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4332
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4333</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4334
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4335<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4336<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4337Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4339<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4343 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4344 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4345</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4347<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4348<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4352 and an address at which to store it. The type of the
4353 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4354 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4355 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4356 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4357 order of execution of this <tt>store</tt> with other <a
4358 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359
4360<p>The optional constant "align" argument specifies the alignment of the
4361 operation (that is, the alignment of the memory address). A value of 0 or an
4362 omitted "align" argument means that the operation has the preferential
4363 alignment for the target. It is the responsibility of the code emitter to
4364 ensure that the alignment information is correct. Overestimating the
4365 alignment results in an undefined behavior. Underestimating the alignment may
4366 produce less efficient code. An alignment of 1 is always safe.</p>
4367
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4368<p>The optional !nontemporal metadata must reference a single metatadata
4369 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4370 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4371 instruction tells the optimizer and code generator that this load is
4372 not expected to be reused in the cache. The code generator may
4373 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4374 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4375
4376
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4377<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4378<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4379 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4380 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4381 does not exceed the minimum number of bytes needed to hold all bits of the
4382 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4383 writing a value of a type like <tt>i20</tt> with a size that is not an
4384 integral number of bytes, it is unspecified what happens to the extra bits
4385 that do not belong to the type, but they will typically be overwritten.</p>
4386
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4387<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388<pre>
4389 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4390 store i32 3, i32* %ptr <i>; yields {void}</i>
4391 %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]4392</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4394</div>
4395
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4396<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4397<div class="doc_subsubsection">
4398 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4399</div>
4400
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4401<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4403<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4404<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4405 &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]4406 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4407</pre>
4408
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4411 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4412 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4413
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4414<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4415<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4416 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4417 elements of the aggregate object are indexed. The interpretation of each
4418 index is dependent on the type being indexed into. The first index always
4419 indexes the pointer value given as the first argument, the second index
4420 indexes a value of the type pointed to (not necessarily the value directly
4421 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4422 indexed into must be a pointer value, subsequent types can be arrays,
4423 vectors, structs and unions. Note that subsequent types being indexed into
4424 can never be pointers, since that would require loading the pointer before
4425 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4426
4427<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4428 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4429 integer <b>constants</b> are allowed. When indexing into an array, pointer
4430 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4431 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4432
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433<p>For example, let's consider a C code fragment and how it gets compiled to
4434 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4435
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4436<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4437<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4438struct RT {
4439 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4440 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4441 char C;
4442};
4443struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4444 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4445 double Y;
4446 struct RT Z;
4447};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4448
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4449int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4450 return &amp;s[1].Z.B[5][13];
4451}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4452</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4453</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4454
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4455<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4456
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4457<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4458<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4459%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4460%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4461
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4462define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4463entry:
4464 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4465 ret i32* %reg
4466}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4467</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4468</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4469
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4470<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4471<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4472 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4473 }</tt>' type, a structure. The second index indexes into the third element
4474 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4475 i8 }</tt>' type, another structure. The third index indexes into the second
4476 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4477 array. The two dimensions of the array are subscripted into, yielding an
4478 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4479 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4480
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4481<p>Note that it is perfectly legal to index partially through a structure,
4482 returning a pointer to an inner element. Because of this, the LLVM code for
4483 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4484
4485<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4486 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4487 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4488 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4489 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4490 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4491 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4492 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4493 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4494</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4495
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4496<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4497 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4498 base pointer is not an <i>in bounds</i> address of an allocated object,
4499 or if any of the addresses that would be formed by successive addition of
4500 the offsets implied by the indices to the base address with infinitely
4501 precise arithmetic are not an <i>in bounds</i> address of that allocated
4502 object. The <i>in bounds</i> addresses for an allocated object are all
4503 the addresses that point into the object, plus the address one byte past
4504 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4505
4506<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4507 the base address with silently-wrapping two's complement arithmetic, and
4508 the result value of the <tt>getelementptr</tt> may be outside the object
4509 pointed to by the base pointer. The result value may not necessarily be
4510 used to access memory though, even if it happens to point into allocated
4511 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4512 section for more information.</p>
4513
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514<p>The getelementptr instruction is often confusing. For some more insight into
4515 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4516
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4517<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4518<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4519 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4520 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4521 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4522 %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]4523 <i>; yields i8*:eptr</i>
4524 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4525 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4526 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4527</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4528
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4529</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4531<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4532<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4533</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4534
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4535<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4536
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4537<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4538 which all take a single operand and a type. They perform various bit
4539 conversions on the operand.</p>
4540
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4541</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4542
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4543<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4544<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4545 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4546</div>
4547<div class="doc_text">
4548
4549<h5>Syntax:</h5>
4550<pre>
4551 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4552</pre>
4553
4554<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4555<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4556 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4557
4558<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4560 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4561 size and type of the result, which must be
4562 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4563 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4564 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4565
4566<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4567<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4568 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4569 source size must be larger than the destination size, <tt>trunc</tt> cannot
4570 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4571
4572<h5>Example:</h5>
4573<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4574 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4575 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4576 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4577</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4578
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4579</div>
4580
4581<!-- _______________________________________________________________________ -->
4582<div class="doc_subsubsection">
4583 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4584</div>
4585<div class="doc_text">
4586
4587<h5>Syntax:</h5>
4588<pre>
4589 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4590</pre>
4591
4592<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4593<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4594 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4595
4596
4597<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4598<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4600 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4601 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603
4604<h5>Semantics:</h5>
4605<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]4606 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4607
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4608<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]4609
4610<h5>Example:</h5>
4611<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4612 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4613 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616</div>
4617
4618<!-- _______________________________________________________________________ -->
4619<div class="doc_subsubsection">
4620 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4621</div>
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
4625<pre>
4626 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4627</pre>
4628
4629<h5>Overview:</h5>
4630<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4631
4632<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4633<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4634 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4635 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4636 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4638
4639<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4641 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4642 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4643
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4644<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]4645
4646<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4647<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4648 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4649 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4652</div>
4653
4654<!-- _______________________________________________________________________ -->
4655<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4656 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4657</div>
4658
4659<div class="doc_text">
4660
4661<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4662<pre>
4663 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4664</pre>
4665
4666<h5>Overview:</h5>
4667<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4668 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
4671<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4673 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]4674 <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]4675 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4676
4677<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4678<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4679 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680 <a href="#t_floating">floating point</a> type. If the value cannot fit
4681 within the destination type, <tt>ty2</tt>, then the results are
4682 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4683
4684<h5>Example:</h5>
4685<pre>
4686 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4687 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4688</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4689
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4690</div>
4691
4692<!-- _______________________________________________________________________ -->
4693<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4694 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4695</div>
4696<div class="doc_text">
4697
4698<h5>Syntax:</h5>
4699<pre>
4700 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4701</pre>
4702
4703<h5>Overview:</h5>
4704<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]4705 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4706
4707<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4708<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4710 a <a href="#t_floating">floating point</a> type to cast it to. The source
4711 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4712
4713<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4714<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715 <a href="#t_floating">floating point</a> type to a larger
4716 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4717 used to make a <i>no-op cast</i> because it always changes bits. Use
4718 <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]4719
4720<h5>Example:</h5>
4721<pre>
4722 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4723 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4724</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4726</div>
4727
4728<!-- _______________________________________________________________________ -->
4729<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4730 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4731</div>
4732<div class="doc_text">
4733
4734<h5>Syntax:</h5>
4735<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4736 &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]4737</pre>
4738
4739<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4740<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4742
4743<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4745 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4746 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4747 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4748 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4749
4750<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4751<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4753 towards zero) unsigned integer value. If the value cannot fit
4754 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4755
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4756<h5>Example:</h5>
4757<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4758 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4759 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4760 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4761</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4767 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4768</div>
4769<div class="doc_text">
4770
4771<h5>Syntax:</h5>
4772<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4773 &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]4774</pre>
4775
4776<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4777<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 <a href="#t_floating">floating point</a> <tt>value</tt> to
4779 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4780
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4781<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4782<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4783 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4784 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4785 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4786 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4787
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4788<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4789<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4791 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4792 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4793
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4794<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4795<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4796 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4797 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4798 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4799</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4801</div>
4802
4803<!-- _______________________________________________________________________ -->
4804<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4805 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4806</div>
4807<div class="doc_text">
4808
4809<h5>Syntax:</h5>
4810<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4811 &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]4812</pre>
4813
4814<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4815<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4816 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4817
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4818<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4819<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]4820 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4821 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4822 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4823 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4824
4825<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4826<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4827 integer quantity and converts it to the corresponding floating point
4828 value. If the value cannot fit in the floating point value, the results are
4829 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4830
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4831<h5>Example:</h5>
4832<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4833 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4834 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4835</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4836
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4837</div>
4838
4839<!-- _______________________________________________________________________ -->
4840<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4841 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4842</div>
4843<div class="doc_text">
4844
4845<h5>Syntax:</h5>
4846<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4847 &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]4848</pre>
4849
4850<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4851<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4852 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4853
4854<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4855<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]4856 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4857 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4858 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4859 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4860
4861<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4863 quantity and converts it to the corresponding floating point value. If the
4864 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4865
4866<h5>Example:</h5>
4867<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4868 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4869 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4870</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4871
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4872</div>
4873
4874<!-- _______________________________________________________________________ -->
4875<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4876 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4877</div>
4878<div class="doc_text">
4879
4880<h5>Syntax:</h5>
4881<pre>
4882 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4883</pre>
4884
4885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4887 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4888
4889<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4890<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4891 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4892 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4893
4894<h5>Semantics:</h5>
4895<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4896 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4897 truncating or zero extending that value to the size of the integer type. If
4898 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4899 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4900 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4901 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4902
4903<h5>Example:</h5>
4904<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4905 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4906 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4908
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4909</div>
4910
4911<!-- _______________________________________________________________________ -->
4912<div class="doc_subsubsection">
4913 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4914</div>
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
4919 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4920</pre>
4921
4922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4924 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4925
4926<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4927<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4928 value to cast, and a type to cast it to, which must be a
4929 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4930
4931<h5>Semantics:</h5>
4932<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4933 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4934 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4935 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4936 than the size of a pointer then a zero extension is done. If they are the
4937 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4938
4939<h5>Example:</h5>
4940<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4941 %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]4942 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4943 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4946</div>
4947
4948<!-- _______________________________________________________________________ -->
4949<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4950 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4951</div>
4952<div class="doc_text">
4953
4954<h5>Syntax:</h5>
4955<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4956 &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]4957</pre>
4958
4959<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4960<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4961 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4962
4963<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4965 non-aggregate first class value, and a type to cast it to, which must also be
4966 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4967 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4968 identical. If the source type is a pointer, the destination type must also be
4969 a pointer. This instruction supports bitwise conversion of vectors to
4970 integers and to vectors of other types (as long as they have the same
4971 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4972
4973<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4974<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4975 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4976 this conversion. The conversion is done as if the <tt>value</tt> had been
4977 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4978 be converted to other pointer types with this instruction. To convert
4979 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4980 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4981
4982<h5>Example:</h5>
4983<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4984 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4985 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4986 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4987</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4988
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4989</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4990
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4991<!-- ======================================================================= -->
4992<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4993
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4994<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995
4996<p>The instructions in this category are the "miscellaneous" instructions, which
4997 defy better classification.</p>
4998
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4999</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5000
5001<!-- _______________________________________________________________________ -->
5002<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5003</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5005<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5007<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5008<pre>
5009 &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]5010</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5011
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5012<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5014 boolean values based on comparison of its two integer, integer vector, or
5015 pointer operands.</p>
5016
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5017<h5>Arguments:</h5>
5018<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019 the condition code indicating the kind of comparison to perform. It is not a
5020 value, just a keyword. The possible condition code are:</p>
5021
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5022<ol>
5023 <li><tt>eq</tt>: equal</li>
5024 <li><tt>ne</tt>: not equal </li>
5025 <li><tt>ugt</tt>: unsigned greater than</li>
5026 <li><tt>uge</tt>: unsigned greater or equal</li>
5027 <li><tt>ult</tt>: unsigned less than</li>
5028 <li><tt>ule</tt>: unsigned less or equal</li>
5029 <li><tt>sgt</tt>: signed greater than</li>
5030 <li><tt>sge</tt>: signed greater or equal</li>
5031 <li><tt>slt</tt>: signed less than</li>
5032 <li><tt>sle</tt>: signed less or equal</li>
5033</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5034
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5035<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5037 typed. They must also be identical types.</p>
5038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5041 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5042 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]5043 result, as follows:</p>
5044
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5045<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5046 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>false</tt> otherwise. No sign interpretation is necessary or
5048 performed.</li>
5049
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5050 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>false</tt> otherwise. No sign interpretation is necessary or
5052 performed.</li>
5053
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5054 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5055 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5056
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5057 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5059 to <tt>op2</tt>.</li>
5060
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5063
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5064 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5065 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5066
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5067 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5069
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5072 to <tt>op2</tt>.</li>
5073
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5074 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5076
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5077 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078 <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]5079</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5081<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082 values are compared as if they were integers.</p>
5083
5084<p>If the operands are integer vectors, then they are compared element by
5085 element. The result is an <tt>i1</tt> vector with the same number of elements
5086 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5087
5088<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089<pre>
5090 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5091 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5092 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5093 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5094 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5095 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5097
5098<p>Note that the code generator does not yet support vector types with
5099 the <tt>icmp</tt> instruction.</p>
5100
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5101</div>
5102
5103<!-- _______________________________________________________________________ -->
5104<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5105</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5107<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5109<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110<pre>
5111 &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]5112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5114<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5116 values based on comparison of its operands.</p>
5117
5118<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]5119(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5120
5121<p>If the operands are floating point vectors, then the result type is a vector
5122 of boolean with the same number of elements as the operands being
5123 compared.</p>
5124
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5125<h5>Arguments:</h5>
5126<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5127 the condition code indicating the kind of comparison to perform. It is not a
5128 value, just a keyword. The possible condition code are:</p>
5129
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5130<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5131 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5132 <li><tt>oeq</tt>: ordered and equal</li>
5133 <li><tt>ogt</tt>: ordered and greater than </li>
5134 <li><tt>oge</tt>: ordered and greater than or equal</li>
5135 <li><tt>olt</tt>: ordered and less than </li>
5136 <li><tt>ole</tt>: ordered and less than or equal</li>
5137 <li><tt>one</tt>: ordered and not equal</li>
5138 <li><tt>ord</tt>: ordered (no nans)</li>
5139 <li><tt>ueq</tt>: unordered or equal</li>
5140 <li><tt>ugt</tt>: unordered or greater than </li>
5141 <li><tt>uge</tt>: unordered or greater than or equal</li>
5142 <li><tt>ult</tt>: unordered or less than </li>
5143 <li><tt>ule</tt>: unordered or less than or equal</li>
5144 <li><tt>une</tt>: unordered or not equal</li>
5145 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5146 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5147</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5148
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5149<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150 <i>unordered</i> means that either operand may be a QNAN.</p>
5151
5152<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5153 a <a href="#t_floating">floating point</a> type or
5154 a <a href="#t_vector">vector</a> of floating point type. They must have
5155 identical types.</p>
5156
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5157<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5158<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5159 according to the condition code given as <tt>cond</tt>. If the operands are
5160 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5161 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162 follows:</p>
5163
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5164<ol>
5165 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5166
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5169
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5170 <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]5171 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5172
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5175
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5176 <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]5177 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5178
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5179 <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]5180 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5181
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5182 <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]5183 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5184
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5185 <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]5186
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5189
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5192
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5195
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5198
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5201
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5204
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5205 <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]5206
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5207 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5208</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5209
5210<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211<pre>
5212 &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]5213 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5214 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5215 &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]5216</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5217
5218<p>Note that the code generator does not yet support vector types with
5219 the <tt>fcmp</tt> instruction.</p>
5220
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5221</div>
5222
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5223<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5224<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5225 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5226</div>
5227
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5228<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5229
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5230<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5231<pre>
5232 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5233</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5234
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5235<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5236<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5237 SSA graph representing the function.</p>
5238
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5239<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240<p>The type of the incoming values is specified with the first type field. After
5241 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5242 one pair for each predecessor basic block of the current block. Only values
5243 of <a href="#t_firstclass">first class</a> type may be used as the value
5244 arguments to the PHI node. Only labels may be used as the label
5245 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5246
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5247<p>There must be no non-phi instructions between the start of a basic block and
5248 the PHI instructions: i.e. PHI instructions must be first in a basic
5249 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5250
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5251<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5252 occur on the edge from the corresponding predecessor block to the current
5253 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5254 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5255
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5256<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5257<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5258 specified by the pair corresponding to the predecessor basic block that
5259 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5260
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5261<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5262<pre>
5263Loop: ; Infinite loop that counts from 0 on up...
5264 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5265 %nextindvar = add i32 %indvar, 1
5266 br label %Loop
5267</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5269</div>
5270
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5271<!-- _______________________________________________________________________ -->
5272<div class="doc_subsubsection">
5273 <a name="i_select">'<tt>select</tt>' Instruction</a>
5274</div>
5275
5276<div class="doc_text">
5277
5278<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5279<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5280 &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>
5281
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5282 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5283</pre>
5284
5285<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5286<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5287 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5288
5289
5290<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5291<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5292 values indicating the condition, and two values of the
5293 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5294 vectors and the condition is a scalar, then entire vectors are selected, not
5295 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5296
5297<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5298<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5299 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5300
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5301<p>If the condition is a vector of i1, then the value arguments must be vectors
5302 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5303
5304<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5305<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5306 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5307</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5308
5309<p>Note that the code generator does not yet support conditions
5310 with vector type.</p>
5311
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5312</div>
5313
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5314<!-- _______________________________________________________________________ -->
5315<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5316 <a name="i_call">'<tt>call</tt>' Instruction</a>
5317</div>
5318
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5319<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5320
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5321<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5322<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5323 &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]5324</pre>
5325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5326<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5327<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5329<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5330<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5331
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5332<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5333 <li>The optional "tail" marker indicates that the callee function does not
5334 access any allocas or varargs in the caller. Note that calls may be
5335 marked "tail" even if they do not occur before
5336 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5337 present, the function call is eligible for tail call optimization,
5338 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5339 optimized into a jump</a>. The code generator may optimize calls marked
5340 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5341 sibling call optimization</a> when the caller and callee have
5342 matching signatures, or 2) forced tail call optimization when the
5343 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5344 <ul>
5345 <li>Caller and callee both have the calling
5346 convention <tt>fastcc</tt>.</li>
5347 <li>The call is in tail position (ret immediately follows call and ret
5348 uses value of call or is void).</li>
5349 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5350 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5351 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5352 constraints are met.</a></li>
5353 </ul>
5354 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5355
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5356 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5357 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5358 defaults to using C calling conventions. The calling convention of the
5359 call must match the calling convention of the target function, or else the
5360 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5362 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5363 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5364 '<tt>inreg</tt>' attributes are valid here.</li>
5365
5366 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5367 type of the return value. Functions that return no value are marked
5368 <tt><a href="#t_void">void</a></tt>.</li>
5369
5370 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5371 being invoked. The argument types must match the types implied by this
5372 signature. This type can be omitted if the function is not varargs and if
5373 the function type does not return a pointer to a function.</li>
5374
5375 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5376 be invoked. In most cases, this is a direct function invocation, but
5377 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5378 to function value.</li>
5379
5380 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5381 signature argument types and parameter attributes. All arguments must be
5382 of <a href="#t_firstclass">first class</a> type. If the function
5383 signature indicates the function accepts a variable number of arguments,
5384 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5385
5386 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5387 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5388 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5389</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5390
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5391<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5392<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5393 a specified function, with its incoming arguments bound to the specified
5394 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5395 function, control flow continues with the instruction after the function
5396 call, and the return value of the function is bound to the result
5397 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5399<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5400<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5401 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5402 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5403 %X = tail call i32 @foo() <i>; yields i32</i>
5404 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5405 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5406
5407 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5408 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5409 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5410 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5411 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5412 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5413</pre>
5414
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5415<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5416standard C99 library as being the C99 library functions, and may perform
5417optimizations or generate code for them under that assumption. This is
5418something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5419freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5421</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5422
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5423<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5424<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5425 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5426</div>
5427
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5428<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5429
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5430<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5431<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5432 &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]5433</pre>
5434
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5435<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5436<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5437 the "variable argument" area of a function call. It is used to implement the
5438 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5439
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5440<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5442 argument. It returns a value of the specified argument type and increments
5443 the <tt>va_list</tt> to point to the next argument. The actual type
5444 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5445
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5448 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5449 to the next argument. For more information, see the variable argument
5450 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5451
5452<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]5453 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5454 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5456<p><tt>va_arg</tt> is an LLVM instruction instead of
5457 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5458 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5459
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5460<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5461<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5462
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463<p>Note that the code generator does not yet fully support va_arg on many
5464 targets. Also, it does not currently support va_arg with aggregate types on
5465 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5467</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5468
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5469<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5470<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5471<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5473<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5474
5475<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5476 well known names and semantics and are required to follow certain
5477 restrictions. Overall, these intrinsics represent an extension mechanism for
5478 the LLVM language that does not require changing all of the transformations
5479 in LLVM when adding to the language (or the bitcode reader/writer, the
5480 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5481
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5482<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5483 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5484 begin with this prefix. Intrinsic functions must always be external
5485 functions: you cannot define the body of intrinsic functions. Intrinsic
5486 functions may only be used in call or invoke instructions: it is illegal to
5487 take the address of an intrinsic function. Additionally, because intrinsic
5488 functions are part of the LLVM language, it is required if any are added that
5489 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5490
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5491<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5492 family of functions that perform the same operation but on different data
5493 types. Because LLVM can represent over 8 million different integer types,
5494 overloading is used commonly to allow an intrinsic function to operate on any
5495 integer type. One or more of the argument types or the result type can be
5496 overloaded to accept any integer type. Argument types may also be defined as
5497 exactly matching a previous argument's type or the result type. This allows
5498 an intrinsic function which accepts multiple arguments, but needs all of them
5499 to be of the same type, to only be overloaded with respect to a single
5500 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5501
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502<p>Overloaded intrinsics will have the names of its overloaded argument types
5503 encoded into its function name, each preceded by a period. Only those types
5504 which are overloaded result in a name suffix. Arguments whose type is matched
5505 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5506 can take an integer of any width and returns an integer of exactly the same
5507 integer width. This leads to a family of functions such as
5508 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5509 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5510 suffix is required. Because the argument's type is matched against the return
5511 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5512
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5513<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5514 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5516</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5517
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5518<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5519<div class="doc_subsection">
5520 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5521</div>
5522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5523<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5524
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5525<p>Variable argument support is defined in LLVM with
5526 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5527 intrinsic functions. These functions are related to the similarly named
5528 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5530<p>All of these functions operate on arguments that use a target-specific value
5531 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5532 not define what this type is, so all transformations should be prepared to
5533 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5534
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5535<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]5536 instruction and the variable argument handling intrinsic functions are
5537 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5538
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5539<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5540<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5541define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5542 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5543 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5544 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5545 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5546
5547 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5548 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5549
5550 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5551 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5552 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5553 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5554 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5555
5556 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5557 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5558 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5559}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5560
5561declare void @llvm.va_start(i8*)
5562declare void @llvm.va_copy(i8*, i8*)
5563declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5564</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5565</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5566
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5567</div>
5568
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5569<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5570<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5571 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5572</div>
5573
5574
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5575<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5577<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5578<pre>
5579 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5580</pre>
5581
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5582<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5583<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5584 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]5585
5586<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5587<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]5588
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5589<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5590<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]5591 macro available in C. In a target-dependent way, it initializes
5592 the <tt>va_list</tt> element to which the argument points, so that the next
5593 call to <tt>va_arg</tt> will produce the first variable argument passed to
5594 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5595 need to know the last argument of the function as the compiler can figure
5596 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5598</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5599
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5600<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5601<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5602 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5603</div>
5604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5605<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5606
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5607<h5>Syntax:</h5>
5608<pre>
5609 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5610</pre>
5611
5612<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5613<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5614 which has been initialized previously
5615 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5616 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5617
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5618<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5619<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]5620
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5621<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5622<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]5623 macro available in C. In a target-dependent way, it destroys
5624 the <tt>va_list</tt> element to which the argument points. Calls
5625 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5626 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5627 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5628
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5629</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5630
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5631<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5632<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5633 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5634</div>
5635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5636<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5637
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5638<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5639<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5640 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5641</pre>
5642
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5643<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5644<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5645 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5646
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5648<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]5649 The second argument is a pointer to a <tt>va_list</tt> element to copy
5650 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5651
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5652<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5653<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]5654 macro available in C. In a target-dependent way, it copies the
5655 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5656 element. This intrinsic is necessary because
5657 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5658 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5659
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5660</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5661
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5662<!-- ======================================================================= -->
5663<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5664 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5665</div>
5666
5667<div class="doc_text">
5668
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5669<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5670Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5671intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5672roots on the stack</a>, as well as garbage collector implementations that
5673require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5674barriers. Front-ends for type-safe garbage collected languages should generate
5675these intrinsics to make use of the LLVM garbage collectors. For more details,
5676see <a href="GarbageCollection.html">Accurate Garbage Collection with
5677LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679<p>The garbage collection intrinsics only operate on objects in the generic
5680 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5681
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5682</div>
5683
5684<!-- _______________________________________________________________________ -->
5685<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5686 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5687</div>
5688
5689<div class="doc_text">
5690
5691<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5692<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5693 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5694</pre>
5695
5696<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5697<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]5698 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5699
5700<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5702 root pointer. The second pointer (which must be either a constant or a
5703 global value address) contains the meta-data to be associated with the
5704 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5705
5706<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5707<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]5708 location. At compile-time, the code generator generates information to allow
5709 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5710 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5711 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712
5713</div>
5714
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715<!-- _______________________________________________________________________ -->
5716<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5717 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718</div>
5719
5720<div class="doc_text">
5721
5722<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5724 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5725</pre>
5726
5727<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5728<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729 locations, allowing garbage collector implementations that require read
5730 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5733<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]5734 allocated from the garbage collector. The first object is a pointer to the
5735 start of the referenced object, if needed by the language runtime (otherwise
5736 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737
5738<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5740 instruction, but may be replaced with substantially more complex code by the
5741 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5742 may only be used in a function which <a href="#gc">specifies a GC
5743 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744
5745</div>
5746
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5747<!-- _______________________________________________________________________ -->
5748<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5749 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5750</div>
5751
5752<div class="doc_text">
5753
5754<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5756 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5757</pre>
5758
5759<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5760<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5761 locations, allowing garbage collector implementations that require write
5762 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5763
5764<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5765<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]5766 object to store it to, and the third is the address of the field of Obj to
5767 store to. If the runtime does not require a pointer to the object, Obj may
5768 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5769
5770<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5771<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772 instruction, but may be replaced with substantially more complex code by the
5773 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5774 may only be used in a function which <a href="#gc">specifies a GC
5775 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5776
5777</div>
5778
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5779<!-- ======================================================================= -->
5780<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5781 <a name="int_codegen">Code Generator Intrinsics</a>
5782</div>
5783
5784<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5785
5786<p>These intrinsics are provided by LLVM to expose special features that may
5787 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788
5789</div>
5790
5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5793 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
5799<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5800 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5801</pre>
5802
5803<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5805 target-specific value indicating the return address of the current function
5806 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809<p>The argument to this intrinsic indicates which function to return the address
5810 for. Zero indicates the calling function, one indicates its caller, etc.
5811 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5812
5813<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5815 indicating the return address of the specified call frame, or zero if it
5816 cannot be identified. The value returned by this intrinsic is likely to be
5817 incorrect or 0 for arguments other than zero, so it should only be used for
5818 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5819
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5820<p>Note that calling this intrinsic does not prevent function inlining or other
5821 aggressive transformations, so the value returned may not be that of the
5822 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5823
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5828 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
5834<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5835 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5836</pre>
5837
5838<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5839<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5840 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5841
5842<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5843<p>The argument to this intrinsic indicates which function to return the frame
5844 pointer for. Zero indicates the calling function, one indicates its caller,
5845 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5846
5847<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5849 indicating the frame address of the specified call frame, or zero if it
5850 cannot be identified. The value returned by this intrinsic is likely to be
5851 incorrect or 0 for arguments other than zero, so it should only be used for
5852 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5854<p>Note that calling this intrinsic does not prevent function inlining or other
5855 aggressive transformations, so the value returned may not be that of the
5856 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5857
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5858</div>
5859
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5860<!-- _______________________________________________________________________ -->
5861<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5862 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5863</div>
5864
5865<div class="doc_text">
5866
5867<h5>Syntax:</h5>
5868<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5869 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5870</pre>
5871
5872<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5874 of the function stack, for use
5875 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5876 useful for implementing language features like scoped automatic variable
5877 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5878
5879<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>This intrinsic returns a opaque pointer value that can be passed
5881 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5882 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5883 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5884 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5885 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5886 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5887
5888</div>
5889
5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5892 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5893</div>
5894
5895<div class="doc_text">
5896
5897<h5>Syntax:</h5>
5898<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5899 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5900</pre>
5901
5902<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5904 the function stack to the state it was in when the
5905 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5906 executed. This is useful for implementing language features like scoped
5907 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5908
5909<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5910<p>See the description
5911 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5912
5913</div>
5914
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5915<!-- _______________________________________________________________________ -->
5916<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5917 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5918</div>
5919
5920<div class="doc_text">
5921
5922<h5>Syntax:</h5>
5923<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5924 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5925</pre>
5926
5927<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5928<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5929 insert a prefetch instruction if supported; otherwise, it is a noop.
5930 Prefetches have no effect on the behavior of the program but can change its
5931 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5932
5933<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5935 specifier determining if the fetch should be for a read (0) or write (1),
5936 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5937 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5938 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5939
5940<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5941<p>This intrinsic does not modify the behavior of the program. In particular,
5942 prefetches cannot trap and do not produce a value. On targets that support
5943 this intrinsic, the prefetch can provide hints to the processor cache for
5944 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5945
5946</div>
5947
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5948<!-- _______________________________________________________________________ -->
5949<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5950 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5951</div>
5952
5953<div class="doc_text">
5954
5955<h5>Syntax:</h5>
5956<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5957 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5958</pre>
5959
5960<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5962 Counter (PC) in a region of code to simulators and other tools. The method
5963 is target specific, but it is expected that the marker will use exported
5964 symbols to transmit the PC of the marker. The marker makes no guarantees
5965 that it will remain with any specific instruction after optimizations. It is
5966 possible that the presence of a marker will inhibit optimizations. The
5967 intended use is to be inserted after optimizations to allow correlations of
5968 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5969
5970<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5972
5973<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5974<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5975 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5976
5977</div>
5978
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5979<!-- _______________________________________________________________________ -->
5980<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5981 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5982</div>
5983
5984<div class="doc_text">
5985
5986<h5>Syntax:</h5>
5987<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5988 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5989</pre>
5990
5991<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5993 counter register (or similar low latency, high accuracy clocks) on those
5994 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5995 should map to RPCC. As the backing counters overflow quickly (on the order
5996 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5997
5998<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5999<p>When directly supported, reading the cycle counter should not modify any
6000 memory. Implementations are allowed to either return a application specific
6001 value or a system wide value. On backends without support, this is lowered
6002 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6003
6004</div>
6005
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6006<!-- ======================================================================= -->
6007<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6008 <a name="int_libc">Standard C Library Intrinsics</a>
6009</div>
6010
6011<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012
6013<p>LLVM provides intrinsics for a few important standard C library functions.
6014 These intrinsics allow source-language front-ends to pass information about
6015 the alignment of the pointer arguments to the code generator, providing
6016 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6017
6018</div>
6019
6020<!-- _______________________________________________________________________ -->
6021<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6022 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6023</div>
6024
6025<div class="doc_text">
6026
6027<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6028<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]6029 integer bit width and for different address spaces. Not all targets support
6030 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6031
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6032<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6033 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6034 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6035 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6036 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6037</pre>
6038
6039<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6040<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6041 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6042
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6044 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6045 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6046
6047<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6048
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049<p>The first argument is a pointer to the destination, the second is a pointer
6050 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6051 number of bytes to copy, the fourth argument is the alignment of the
6052 source and destination locations, and the fifth is a boolean indicating a
6053 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6054
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6055<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]6056 then the caller guarantees that both the source and destination pointers are
6057 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6058
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6059<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6060 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6061 The detailed access behavior is not very cleanly specified and it is unwise
6062 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6063
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6064<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6067 source location to the destination location, which are not allowed to
6068 overlap. It copies "len" bytes of memory over. If the argument is known to
6069 be aligned to some boundary, this can be specified as the fourth argument,
6070 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6071
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6072</div>
6073
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6074<!-- _______________________________________________________________________ -->
6075<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6076 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6077</div>
6078
6079<div class="doc_text">
6080
6081<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6082<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]6083 width and for different address space. Not all targets support all bit
6084 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6085
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6086<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6087 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6088 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6089 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6090 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6091</pre>
6092
6093<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6094<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6095 source location to the destination location. It is similar to the
6096 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6097 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6098
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6100 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6101 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6102
6103<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6105<p>The first argument is a pointer to the destination, the second is a pointer
6106 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6107 number of bytes to copy, the fourth argument is the alignment of the
6108 source and destination locations, and the fifth is a boolean indicating a
6109 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6110
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6111<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]6112 then the caller guarantees that the source and destination pointers are
6113 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6114
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6115<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6116 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6117 The detailed access behavior is not very cleanly specified and it is unwise
6118 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6119
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6120<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6123 source location to the destination location, which may overlap. It copies
6124 "len" bytes of memory over. If the argument is known to be aligned to some
6125 boundary, this can be specified as the fourth argument, otherwise it should
6126 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6127
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128</div>
6129
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6130<!-- _______________________________________________________________________ -->
6131<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6132 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6133</div>
6134
6135<div class="doc_text">
6136
6137<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6138<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6139 width and for different address spaces. Not all targets support all bit
6140 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6141
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6142<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6143 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6144 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6145 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6146 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6147</pre>
6148
6149<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6150<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6151 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6152
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6153<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6154 intrinsic does not return a value, takes extra alignment/volatile arguments,
6155 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6156
6157<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6158<p>The first argument is a pointer to the destination to fill, the second is the
6159 byte value to fill it with, the third argument is an integer argument
6160 specifying the number of bytes to fill, and the fourth argument is the known
6161 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6162
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6163<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]6164 then the caller guarantees that the destination pointer is aligned to that
6165 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6166
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6167<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6168 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6169 The detailed access behavior is not very cleanly specified and it is unwise
6170 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6171
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6172<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6174 at the destination location. If the argument is known to be aligned to some
6175 boundary, this can be specified as the fourth argument, otherwise it should
6176 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6177
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6178</div>
6179
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6180<!-- _______________________________________________________________________ -->
6181<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6182 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6183</div>
6184
6185<div class="doc_text">
6186
6187<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6188<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6189 floating point or vector of floating point type. Not all targets support all
6190 types however.</p>
6191
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6192<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6193 declare float @llvm.sqrt.f32(float %Val)
6194 declare double @llvm.sqrt.f64(double %Val)
6195 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6196 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6197 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6198</pre>
6199
6200<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6201<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6202 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6203 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6204 behavior for negative numbers other than -0.0 (which allows for better
6205 optimization, because there is no need to worry about errno being
6206 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]6207
6208<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209<p>The argument and return value are floating point numbers of the same
6210 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6211
6212<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6213<p>This function returns the sqrt of the specified operand if it is a
6214 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6215
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6216</div>
6217
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6220 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6226<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6227 floating point or vector of floating point type. Not all targets support all
6228 types however.</p>
6229
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6230<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6231 declare float @llvm.powi.f32(float %Val, i32 %power)
6232 declare double @llvm.powi.f64(double %Val, i32 %power)
6233 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6234 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6235 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6236</pre>
6237
6238<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6240 specified (positive or negative) power. The order of evaluation of
6241 multiplications is not defined. When a vector of floating point type is
6242 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6243
6244<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6245<p>The second argument is an integer power, and the first is a value to raise to
6246 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6247
6248<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6249<p>This function returns the first value raised to the second power with an
6250 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6251
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6252</div>
6253
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
6256 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6257</div>
6258
6259<div class="doc_text">
6260
6261<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6262<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6263 floating point or vector of floating point type. Not all targets support all
6264 types however.</p>
6265
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6266<pre>
6267 declare float @llvm.sin.f32(float %Val)
6268 declare double @llvm.sin.f64(double %Val)
6269 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6270 declare fp128 @llvm.sin.f128(fp128 %Val)
6271 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6272</pre>
6273
6274<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6275<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6276
6277<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6278<p>The argument and return value are floating point numbers of the same
6279 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6280
6281<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6282<p>This function returns the sine of the specified operand, returning the same
6283 values as the libm <tt>sin</tt> functions would, and handles error conditions
6284 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6285
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6286</div>
6287
6288<!-- _______________________________________________________________________ -->
6289<div class="doc_subsubsection">
6290 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6291</div>
6292
6293<div class="doc_text">
6294
6295<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6296<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6297 floating point or vector of floating point type. Not all targets support all
6298 types however.</p>
6299
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6300<pre>
6301 declare float @llvm.cos.f32(float %Val)
6302 declare double @llvm.cos.f64(double %Val)
6303 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6304 declare fp128 @llvm.cos.f128(fp128 %Val)
6305 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6306</pre>
6307
6308<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6309<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>The argument and return value are floating point numbers of the same
6313 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6314
6315<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6316<p>This function returns the cosine of the specified operand, returning the same
6317 values as the libm <tt>cos</tt> functions would, and handles error conditions
6318 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6319
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6320</div>
6321
6322<!-- _______________________________________________________________________ -->
6323<div class="doc_subsubsection">
6324 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6325</div>
6326
6327<div class="doc_text">
6328
6329<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6330<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6331 floating point or vector of floating point type. Not all targets support all
6332 types however.</p>
6333
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6334<pre>
6335 declare float @llvm.pow.f32(float %Val, float %Power)
6336 declare double @llvm.pow.f64(double %Val, double %Power)
6337 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6338 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6339 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6340</pre>
6341
6342<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6343<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6344 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6345
6346<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347<p>The second argument is a floating point power, and the first is a value to
6348 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6349
6350<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6351<p>This function returns the first value raised to the second power, returning
6352 the same values as the libm <tt>pow</tt> functions would, and handles error
6353 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6354
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6355</div>
6356
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6357<!-- ======================================================================= -->
6358<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6359 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6360</div>
6361
6362<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6363
6364<p>LLVM provides intrinsics for a few important bit manipulation operations.
6365 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6366
6367</div>
6368
6369<!-- _______________________________________________________________________ -->
6370<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6371 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6372</div>
6373
6374<div class="doc_text">
6375
6376<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6377<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6378 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6379
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6380<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6381 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6382 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6383 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6384</pre>
6385
6386<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6388 values with an even number of bytes (positive multiple of 16 bits). These
6389 are useful for performing operations on data that is not in the target's
6390 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6393<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6394 and low byte of the input i16 swapped. Similarly,
6395 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6396 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6397 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6398 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6399 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6400 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6401
6402</div>
6403
6404<!-- _______________________________________________________________________ -->
6405<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6406 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6407</div>
6408
6409<div class="doc_text">
6410
6411<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6412<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6413 width. Not all targets support all bit widths however.</p>
6414
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6415<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6416 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6417 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6418 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6419 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6420 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6425 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6426
6427<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428<p>The only argument is the value to be counted. The argument may be of any
6429 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6430
6431<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6433
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6434</div>
6435
6436<!-- _______________________________________________________________________ -->
6437<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6438 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6439</div>
6440
6441<div class="doc_text">
6442
6443<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6444<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6445 integer bit width. Not all targets support all bit widths however.</p>
6446
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6447<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6448 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6449 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6450 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6451 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6452 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6453</pre>
6454
6455<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6457 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6458
6459<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6460<p>The only argument is the value to be counted. The argument may be of any
6461 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6462
6463<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6465 zeros in a variable. If the src == 0 then the result is the size in bits of
6466 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6467
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6468</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6469
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6470<!-- _______________________________________________________________________ -->
6471<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6472 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6473</div>
6474
6475<div class="doc_text">
6476
6477<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6478<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6479 integer bit width. Not all targets support all bit widths however.</p>
6480
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6481<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6482 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6483 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6484 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6485 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6486 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6487</pre>
6488
6489<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6491 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6492
6493<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494<p>The only argument is the value to be counted. The argument may be of any
6495 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6496
6497<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6499 zeros in a variable. If the src == 0 then the result is the size in bits of
6500 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6501
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6502</div>
6503
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6504<!-- ======================================================================= -->
6505<div class="doc_subsection">
6506 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6507</div>
6508
6509<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510
6511<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6512
6513</div>
6514
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6515<!-- _______________________________________________________________________ -->
6516<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6517 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6518</div>
6519
6520<div class="doc_text">
6521
6522<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6523<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]6524 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6525
6526<pre>
6527 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6528 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6529 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6530</pre>
6531
6532<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6533<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6534 a signed addition of the two arguments, and indicate whether an overflow
6535 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6536
6537<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6538<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]6539 be of integer types of any bit width, but they must have the same bit
6540 width. The second element of the result structure must be of
6541 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6542 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6543
6544<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6545<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6546 a signed addition of the two variables. They return a structure &mdash; the
6547 first element of which is the signed summation, and the second element of
6548 which is a bit specifying if the signed summation resulted in an
6549 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Examples:</h5>
6552<pre>
6553 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6554 %sum = extractvalue {i32, i1} %res, 0
6555 %obit = extractvalue {i32, i1} %res, 1
6556 br i1 %obit, label %overflow, label %normal
6557</pre>
6558
6559</div>
6560
6561<!-- _______________________________________________________________________ -->
6562<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6563 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6564</div>
6565
6566<div class="doc_text">
6567
6568<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6569<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]6570 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6571
6572<pre>
6573 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6574 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6575 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6576</pre>
6577
6578<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6579<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6580 an unsigned addition of the two arguments, and indicate whether a carry
6581 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6582
6583<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6584<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]6585 be of integer types of any bit width, but they must have the same bit
6586 width. The second element of the result structure must be of
6587 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6588 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6589
6590<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6591<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6592 an unsigned addition of the two arguments. They return a structure &mdash;
6593 the first element of which is the sum, and the second element of which is a
6594 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6595
6596<h5>Examples:</h5>
6597<pre>
6598 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6599 %sum = extractvalue {i32, i1} %res, 0
6600 %obit = extractvalue {i32, i1} %res, 1
6601 br i1 %obit, label %carry, label %normal
6602</pre>
6603
6604</div>
6605
6606<!-- _______________________________________________________________________ -->
6607<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6608 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6609</div>
6610
6611<div class="doc_text">
6612
6613<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6614<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]6615 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6616
6617<pre>
6618 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6619 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6620 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6621</pre>
6622
6623<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6624<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6625 a signed subtraction of the two arguments, and indicate whether an overflow
6626 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6627
6628<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6629<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]6630 be of integer types of any bit width, but they must have the same bit
6631 width. The second element of the result structure must be of
6632 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6633 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6634
6635<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6636<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6637 a signed subtraction of the two arguments. They return a structure &mdash;
6638 the first element of which is the subtraction, and the second element of
6639 which is a bit specifying if the signed subtraction resulted in an
6640 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Examples:</h5>
6643<pre>
6644 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6645 %sum = extractvalue {i32, i1} %res, 0
6646 %obit = extractvalue {i32, i1} %res, 1
6647 br i1 %obit, label %overflow, label %normal
6648</pre>
6649
6650</div>
6651
6652<!-- _______________________________________________________________________ -->
6653<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6654 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6655</div>
6656
6657<div class="doc_text">
6658
6659<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6660<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]6661 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6662
6663<pre>
6664 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6665 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6666 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6667</pre>
6668
6669<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6670<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6671 an unsigned subtraction of the two arguments, and indicate whether an
6672 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6673
6674<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6675<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]6676 be of integer types of any bit width, but they must have the same bit
6677 width. The second element of the result structure must be of
6678 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6679 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6680
6681<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6682<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6683 an unsigned subtraction of the two arguments. They return a structure &mdash;
6684 the first element of which is the subtraction, and the second element of
6685 which is a bit specifying if the unsigned subtraction resulted in an
6686 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6687
6688<h5>Examples:</h5>
6689<pre>
6690 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6691 %sum = extractvalue {i32, i1} %res, 0
6692 %obit = extractvalue {i32, i1} %res, 1
6693 br i1 %obit, label %overflow, label %normal
6694</pre>
6695
6696</div>
6697
6698<!-- _______________________________________________________________________ -->
6699<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6700 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6701</div>
6702
6703<div class="doc_text">
6704
6705<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6706<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]6707 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6708
6709<pre>
6710 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6711 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6712 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6713</pre>
6714
6715<h5>Overview:</h5>
6716
6717<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6718 a signed multiplication of the two arguments, and indicate whether an
6719 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6720
6721<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6722<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]6723 be of integer types of any bit width, but they must have the same bit
6724 width. The second element of the result structure must be of
6725 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6726 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6727
6728<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6729<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6730 a signed multiplication of the two arguments. They return a structure &mdash;
6731 the first element of which is the multiplication, and the second element of
6732 which is a bit specifying if the signed multiplication resulted in an
6733 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6734
6735<h5>Examples:</h5>
6736<pre>
6737 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6738 %sum = extractvalue {i32, i1} %res, 0
6739 %obit = extractvalue {i32, i1} %res, 1
6740 br i1 %obit, label %overflow, label %normal
6741</pre>
6742
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6743</div>
6744
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6745<!-- _______________________________________________________________________ -->
6746<div class="doc_subsubsection">
6747 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6748</div>
6749
6750<div class="doc_text">
6751
6752<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6753<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]6754 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6755
6756<pre>
6757 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6758 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6759 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6760</pre>
6761
6762<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6763<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6764 a unsigned multiplication of the two arguments, and indicate whether an
6765 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6766
6767<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6768<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]6769 be of integer types of any bit width, but they must have the same bit
6770 width. The second element of the result structure must be of
6771 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6772 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6773
6774<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6775<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6776 an unsigned multiplication of the two arguments. They return a structure
6777 &mdash; the first element of which is the multiplication, and the second
6778 element of which is a bit specifying if the unsigned multiplication resulted
6779 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6780
6781<h5>Examples:</h5>
6782<pre>
6783 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6784 %sum = extractvalue {i32, i1} %res, 0
6785 %obit = extractvalue {i32, i1} %res, 1
6786 br i1 %obit, label %overflow, label %normal
6787</pre>
6788
6789</div>
6790
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6791<!-- ======================================================================= -->
6792<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6793 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6794</div>
6795
6796<div class="doc_text">
6797
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6798<p>Half precision floating point is a storage-only format. This means that it is
6799 a dense encoding (in memory) but does not support computation in the
6800 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6801
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6802<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6803 value as an i16, then convert it to float with <a
6804 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6805 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6806 double etc). To store the value back to memory, it is first converted to
6807 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6808 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6809 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6810</div>
6811
6812<!-- _______________________________________________________________________ -->
6813<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6814 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6815</div>
6816
6817<div class="doc_text">
6818
6819<h5>Syntax:</h5>
6820<pre>
6821 declare i16 @llvm.convert.to.fp16(f32 %a)
6822</pre>
6823
6824<h5>Overview:</h5>
6825<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6826 a conversion from single precision floating point format to half precision
6827 floating point format.</p>
6828
6829<h5>Arguments:</h5>
6830<p>The intrinsic function contains single argument - the value to be
6831 converted.</p>
6832
6833<h5>Semantics:</h5>
6834<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6835 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6836 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6837 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6838
6839<h5>Examples:</h5>
6840<pre>
6841 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6842 store i16 %res, i16* @x, align 2
6843</pre>
6844
6845</div>
6846
6847<!-- _______________________________________________________________________ -->
6848<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6849 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6850</div>
6851
6852<div class="doc_text">
6853
6854<h5>Syntax:</h5>
6855<pre>
6856 declare f32 @llvm.convert.from.fp16(i16 %a)
6857</pre>
6858
6859<h5>Overview:</h5>
6860<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6861 a conversion from half precision floating point format to single precision
6862 floating point format.</p>
6863
6864<h5>Arguments:</h5>
6865<p>The intrinsic function contains single argument - the value to be
6866 converted.</p>
6867
6868<h5>Semantics:</h5>
6869<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6870 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6871 precision floating point format. The input half-float value is represented by
6872 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6873
6874<h5>Examples:</h5>
6875<pre>
6876 %a = load i16* @x, align 2
6877 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6878</pre>
6879
6880</div>
6881
6882<!-- ======================================================================= -->
6883<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6884 <a name="int_debugger">Debugger Intrinsics</a>
6885</div>
6886
6887<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6888
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6889<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6890 prefix), are described in
6891 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6892 Level Debugging</a> document.</p>
6893
6894</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6895
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6896<!-- ======================================================================= -->
6897<div class="doc_subsection">
6898 <a name="int_eh">Exception Handling Intrinsics</a>
6899</div>
6900
6901<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6902
6903<p>The LLVM exception handling intrinsics (which all start with
6904 <tt>llvm.eh.</tt> prefix), are described in
6905 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6906 Handling</a> document.</p>
6907
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6908</div>
6909
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6910<!-- ======================================================================= -->
6911<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6912 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6913</div>
6914
6915<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916
6917<p>This intrinsic makes it possible to excise one parameter, marked with
6918 the <tt>nest</tt> attribute, from a function. The result is a callable
6919 function pointer lacking the nest parameter - the caller does not need to
6920 provide a value for it. Instead, the value to use is stored in advance in a
6921 "trampoline", a block of memory usually allocated on the stack, which also
6922 contains code to splice the nest value into the argument list. This is used
6923 to implement the GCC nested function address extension.</p>
6924
6925<p>For example, if the function is
6926 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6927 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6928 follows:</p>
6929
6930<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6931<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6932 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6933 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6934 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6935 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6936</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6937</div>
6938
6939<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6940 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6941
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6942</div>
6943
6944<!-- _______________________________________________________________________ -->
6945<div class="doc_subsubsection">
6946 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6947</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6948
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6949<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6951<h5>Syntax:</h5>
6952<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953 declare i8* @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]6954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6955
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6956<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6957<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6958 function pointer suitable for executing it.</p>
6959
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6960<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6961<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6962 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6963 sufficiently aligned block of memory; this memory is written to by the
6964 intrinsic. Note that the size and the alignment are target-specific - LLVM
6965 currently provides no portable way of determining them, so a front-end that
6966 generates this intrinsic needs to have some target-specific knowledge.
6967 The <tt>func</tt> argument must hold a function bitcast to
6968 an <tt>i8*</tt>.</p>
6969
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6970<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6971<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6972 dependent code, turning it into a function. A pointer to this function is
6973 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6974 function pointer type</a> before being called. The new function's signature
6975 is the same as that of <tt>func</tt> with any arguments marked with
6976 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6977 is allowed, and it must be of pointer type. Calling the new function is
6978 equivalent to calling <tt>func</tt> with the same argument list, but
6979 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6980 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6981 by <tt>tramp</tt> is modified, then the effect of any later call to the
6982 returned function pointer is undefined.</p>
6983
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6984</div>
6985
6986<!-- ======================================================================= -->
6987<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6988 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6989</div>
6990
6991<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6994 hardware constructs for atomic operations and memory synchronization. This
6995 provides an interface to the hardware, not an interface to the programmer. It
6996 is aimed at a low enough level to allow any programming models or APIs
6997 (Application Programming Interfaces) which need atomic behaviors to map
6998 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6999 hardware provides a "universal IR" for source languages, it also provides a
7000 starting point for developing a "universal" atomic operation and
7001 synchronization IR.</p>
7002
7003<p>These do <em>not</em> form an API such as high-level threading libraries,
7004 software transaction memory systems, atomic primitives, and intrinsic
7005 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7006 application libraries. The hardware interface provided by LLVM should allow
7007 a clean implementation of all of these APIs and parallel programming models.
7008 No one model or paradigm should be selected above others unless the hardware
7009 itself ubiquitously does so.</p>
7010
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7011</div>
7012
7013<!-- _______________________________________________________________________ -->
7014<div class="doc_subsubsection">
7015 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7016</div>
7017<div class="doc_text">
7018<h5>Syntax:</h5>
7019<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7020 declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt; )
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7021</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7022
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7023<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7025 specific pairs of memory access types.</p>
7026
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7027<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7028<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7029 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7030 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7032
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7033<ul>
7034 <li><tt>ll</tt>: load-load barrier</li>
7035 <li><tt>ls</tt>: load-store barrier</li>
7036 <li><tt>sl</tt>: store-load barrier</li>
7037 <li><tt>ss</tt>: store-store barrier</li>
7038 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7039</ul>
7040
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7042<p>This intrinsic causes the system to enforce some ordering constraints upon
7043 the loads and stores of the program. This barrier does not
7044 indicate <em>when</em> any events will occur, it only enforces
7045 an <em>order</em> in which they occur. For any of the specified pairs of load
7046 and store operations (f.ex. load-load, or store-load), all of the first
7047 operations preceding the barrier will complete before any of the second
7048 operations succeeding the barrier begin. Specifically the semantics for each
7049 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7050
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051<ul>
7052 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7053 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7054 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7055 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7056 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7057 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7058 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7059 load after the barrier begins.</li>
7060</ul>
7061
7062<p>These semantics are applied with a logical "and" behavior when more than one
7063 is enabled in a single memory barrier intrinsic.</p>
7064
7065<p>Backends may implement stronger barriers than those requested when they do
7066 not support as fine grained a barrier as requested. Some architectures do
7067 not need all types of barriers and on such architectures, these become
7068 noops.</p>
7069
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7070<h5>Example:</h5>
7071<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7072%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7073%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7074 store i32 4, %ptr
7075
7076%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7077 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7078 <i>; guarantee the above finishes</i>
7079 store i32 8, %ptr <i>; before this begins</i>
7080</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7082</div>
7083
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
7085<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7086 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7087</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7088
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7089<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7091<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7092<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7093 any integer bit width and for different address spaces. Not all targets
7094 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7095
7096<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7098 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7099 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7100 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7101</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7102
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7103<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7104<p>This loads a value in memory and compares it to a given value. If they are
7105 equal, it stores a new value into the memory.</p>
7106
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7107<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7109 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7110 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7111 this integer type. While any bit width integer may be used, targets may only
7112 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7113
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7114<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7115<p>This entire intrinsic must be executed atomically. It first loads the value
7116 in memory pointed to by <tt>ptr</tt> and compares it with the
7117 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7118 memory. The loaded value is yielded in all cases. This provides the
7119 equivalent of an atomic compare-and-swap operation within the SSA
7120 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7122<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7123<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7124%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7125%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7126 store i32 4, %ptr
7127
7128%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7129%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7130 <i>; yields {i32}:result1 = 4</i>
7131%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7132%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7133
7134%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7135%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136 <i>; yields {i32}:result2 = 8</i>
7137%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7138
7139%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7140</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7141
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7142</div>
7143
7144<!-- _______________________________________________________________________ -->
7145<div class="doc_subsubsection">
7146 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7147</div>
7148<div class="doc_text">
7149<h5>Syntax:</h5>
7150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7151<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7152 integer bit width. Not all targets support all bit widths however.</p>
7153
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7154<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7155 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7156 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7157 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7158 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7161<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7163 the value from memory. It then stores the value in <tt>val</tt> in the memory
7164 at <tt>ptr</tt>.</p>
7165
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7168 the <tt>val</tt> argument and the result must be integers of the same bit
7169 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7170 integer type. The targets may only lower integer representations they
7171 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7172
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7173<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7175 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7176 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7177
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7178<h5>Examples:</h5>
7179<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7180%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7181%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7182 store i32 4, %ptr
7183
7184%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7185%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186 <i>; yields {i32}:result1 = 4</i>
7187%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7188%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7189
7190%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7191%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7192 <i>; yields {i32}:result2 = 8</i>
7193
7194%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7195%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7196</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7197
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7198</div>
7199
7200<!-- _______________________________________________________________________ -->
7201<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7202 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203
7204</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7207
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7208<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7209<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7210 any integer bit width. Not all targets support all bit widths however.</p>
7211
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7212<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7213 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7214 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7215 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7216 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7217</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7218
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219<h5>Overview:</h5>
7220<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7221 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7222
7223<h5>Arguments:</h5>
7224<p>The intrinsic takes two arguments, the first a pointer to an integer value
7225 and the second an integer value. The result is also an integer value. These
7226 integer types can have any bit width, but they must all have the same bit
7227 width. The targets may only lower integer representations they support.</p>
7228
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7229<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230<p>This intrinsic does a series of operations atomically. It first loads the
7231 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7232 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7233
7234<h5>Examples:</h5>
7235<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7236%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7237%ptr = bitcast i8* %mallocP to i32*
7238 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7239%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7240 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7241%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7242 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7243%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7244 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7245%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7246</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7247
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7248</div>
7249
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7250<!-- _______________________________________________________________________ -->
7251<div class="doc_subsubsection">
7252 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7253
7254</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7256<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7258<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7259<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7260 any integer bit width and for different address spaces. Not all targets
7261 support all bit widths however.</p>
7262
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7263<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7264 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7265 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7266 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7267 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7268</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7270<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7271<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7272 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7273
7274<h5>Arguments:</h5>
7275<p>The intrinsic takes two arguments, the first a pointer to an integer value
7276 and the second an integer value. The result is also an integer value. These
7277 integer types can have any bit width, but they must all have the same bit
7278 width. The targets may only lower integer representations they support.</p>
7279
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7280<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281<p>This intrinsic does a series of operations atomically. It first loads the
7282 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7283 result to <tt>ptr</tt>. It yields the original value stored
7284 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7285
7286<h5>Examples:</h5>
7287<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7288%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7289%ptr = bitcast i8* %mallocP to i32*
7290 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7291%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7292 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7293%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7294 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7295%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7296 <i>; yields {i32}:result3 = 2</i>
7297%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7300</div>
7301
7302<!-- _______________________________________________________________________ -->
7303<div class="doc_subsubsection">
7304 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7305 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7306 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7307 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7308</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7309
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7310<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7312<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7313<p>These are overloaded intrinsics. You can
7314 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7315 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7316 bit width and for different address spaces. Not all targets support all bit
7317 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319<pre>
7320 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7321 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7322 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7323 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7324</pre>
7325
7326<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7327 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7328 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7329 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7330 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7331</pre>
7332
7333<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7334 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7335 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7336 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7337 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338</pre>
7339
7340<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7341 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7342 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7343 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7344 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7345</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7346
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7347<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7349 the value stored in memory at <tt>ptr</tt>. It yields the original value
7350 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352<h5>Arguments:</h5>
7353<p>These intrinsics take two arguments, the first a pointer to an integer value
7354 and the second an integer value. The result is also an integer value. These
7355 integer types can have any bit width, but they must all have the same bit
7356 width. The targets may only lower integer representations they support.</p>
7357
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7358<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7359<p>These intrinsics does a series of operations atomically. They first load the
7360 value stored at <tt>ptr</tt>. They then do the bitwise
7361 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7362 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7363
7364<h5>Examples:</h5>
7365<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7366%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7367%ptr = bitcast i8* %mallocP to i32*
7368 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7369%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7370 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7371%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7372 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7373%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7374 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7375%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7376 <i>; yields {i32}:result3 = FF</i>
7377%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7378</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7379
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7380</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7381
7382<!-- _______________________________________________________________________ -->
7383<div class="doc_subsubsection">
7384 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7385 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7386 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7387 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7388</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7389
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7392<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7393<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7394 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7395 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7396 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7397
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7398<pre>
7399 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7400 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7401 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7402 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7403</pre>
7404
7405<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7406 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7407 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7408 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7409 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410</pre>
7411
7412<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7413 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7414 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7415 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7416 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7417</pre>
7418
7419<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7420 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7421 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7422 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7423 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7425
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7426<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7427<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7428 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7429 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7430
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7431<h5>Arguments:</h5>
7432<p>These intrinsics take two arguments, the first a pointer to an integer value
7433 and the second an integer value. The result is also an integer value. These
7434 integer types can have any bit width, but they must all have the same bit
7435 width. The targets may only lower integer representations they support.</p>
7436
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7437<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7438<p>These intrinsics does a series of operations atomically. They first load the
7439 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7440 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7441 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7442
7443<h5>Examples:</h5>
7444<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7445%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7446%ptr = bitcast i8* %mallocP to i32*
7447 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7448%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7449 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7450%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7451 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7452%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7453 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7454%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7455 <i>; yields {i32}:result3 = 8</i>
7456%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7457</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7458
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7459</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7460
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7461
7462<!-- ======================================================================= -->
7463<div class="doc_subsection">
7464 <a name="int_memorymarkers">Memory Use Markers</a>
7465</div>
7466
7467<div class="doc_text">
7468
7469<p>This class of intrinsics exists to information about the lifetime of memory
7470 objects and ranges where variables are immutable.</p>
7471
7472</div>
7473
7474<!-- _______________________________________________________________________ -->
7475<div class="doc_subsubsection">
7476 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7477</div>
7478
7479<div class="doc_text">
7480
7481<h5>Syntax:</h5>
7482<pre>
7483 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7484</pre>
7485
7486<h5>Overview:</h5>
7487<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7488 object's lifetime.</p>
7489
7490<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7491<p>The first argument is a constant integer representing the size of the
7492 object, or -1 if it is variable sized. The second argument is a pointer to
7493 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7494
7495<h5>Semantics:</h5>
7496<p>This intrinsic indicates that before this point in the code, the value of the
7497 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]7498 never be used and has an undefined value. A load from the pointer that
7499 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7500 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7501
7502</div>
7503
7504<!-- _______________________________________________________________________ -->
7505<div class="doc_subsubsection">
7506 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7507</div>
7508
7509<div class="doc_text">
7510
7511<h5>Syntax:</h5>
7512<pre>
7513 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7514</pre>
7515
7516<h5>Overview:</h5>
7517<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7518 object's lifetime.</p>
7519
7520<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7521<p>The first argument is a constant integer representing the size of the
7522 object, or -1 if it is variable sized. The second argument is a pointer to
7523 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7524
7525<h5>Semantics:</h5>
7526<p>This intrinsic indicates that after this point in the code, the value of the
7527 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7528 never be used and has an undefined value. Any stores into the memory object
7529 following this intrinsic may be removed as dead.
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7547 a memory object will not change.</p>
7548
7549<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7550<p>The first argument is a constant integer representing the size of the
7551 object, or -1 if it is variable sized. The second argument is a pointer to
7552 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7553
7554<h5>Semantics:</h5>
7555<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7556 the return value, the referenced memory location is constant and
7557 unchanging.</p>
7558
7559</div>
7560
7561<!-- _______________________________________________________________________ -->
7562<div class="doc_subsubsection">
7563 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7564</div>
7565
7566<div class="doc_text">
7567
7568<h5>Syntax:</h5>
7569<pre>
7570 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7571</pre>
7572
7573<h5>Overview:</h5>
7574<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7575 a memory object are mutable.</p>
7576
7577<h5>Arguments:</h5>
7578<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7579 The second argument is a constant integer representing the size of the
7580 object, or -1 if it is variable sized and the third argument is a pointer
7581 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7582
7583<h5>Semantics:</h5>
7584<p>This intrinsic indicates that the memory is mutable again.</p>
7585
7586</div>
7587
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7588<!-- ======================================================================= -->
7589<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7590 <a name="int_general">General Intrinsics</a>
7591</div>
7592
7593<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7594
7595<p>This class of intrinsics is designed to be generic and has no specific
7596 purpose.</p>
7597
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7598</div>
7599
7600<!-- _______________________________________________________________________ -->
7601<div class="doc_subsubsection">
7602 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7603</div>
7604
7605<div class="doc_text">
7606
7607<h5>Syntax:</h5>
7608<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7609 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]7610</pre>
7611
7612<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7613<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7614
7615<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7616<p>The first argument is a pointer to a value, the second is a pointer to a
7617 global string, the third is a pointer to a global string which is the source
7618 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7619
7620<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7621<p>This intrinsic allows annotation of local variables with arbitrary strings.
7622 This can be useful for special purpose optimizations that want to look for
7623 these annotations. These have no other defined use, they are ignored by code
7624 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7625
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7626</div>
7627
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7628<!-- _______________________________________________________________________ -->
7629<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7630 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7631</div>
7632
7633<div class="doc_text">
7634
7635<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7636<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7637 any integer bit width.</p>
7638
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7639<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7640 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7641 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7642 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7643 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7644 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]7645</pre>
7646
7647<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7648<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7649
7650<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7651<p>The first argument is an integer value (result of some expression), the
7652 second is a pointer to a global string, the third is a pointer to a global
7653 string which is the source file name, and the last argument is the line
7654 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7655
7656<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7657<p>This intrinsic allows annotations to be put on arbitrary expressions with
7658 arbitrary strings. This can be useful for special purpose optimizations that
7659 want to look for these annotations. These have no other defined use, they
7660 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7661
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7662</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7663
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7664<!-- _______________________________________________________________________ -->
7665<div class="doc_subsubsection">
7666 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7667</div>
7668
7669<div class="doc_text">
7670
7671<h5>Syntax:</h5>
7672<pre>
7673 declare void @llvm.trap()
7674</pre>
7675
7676<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7677<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7678
7679<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7680<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7681
7682<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683<p>This intrinsics is lowered to the target dependent trap instruction. If the
7684 target does not have a trap instruction, this intrinsic will be lowered to
7685 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7686
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7687</div>
7688
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7689<!-- _______________________________________________________________________ -->
7690<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7691 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7692</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7693
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7694<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7695
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7696<h5>Syntax:</h5>
7697<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7698 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7699</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7700
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7701<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7702<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7703 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7704 ensure that it is placed on the stack before local variables.</p>
7705
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7706<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7707<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7708 arguments. The first argument is the value loaded from the stack
7709 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7710 that has enough space to hold the value of the guard.</p>
7711
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7712<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7713<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7714 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7715 stack. This is to ensure that if a local variable on the stack is
7716 overwritten, it will destroy the value of the guard. When the function exits,
7717 the guard on the stack is checked against the original guard. If they're
7718 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7719 function.</p>
7720
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7721</div>
7722
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7723<!-- _______________________________________________________________________ -->
7724<div class="doc_subsubsection">
7725 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7726</div>
7727
7728<div class="doc_text">
7729
7730<h5>Syntax:</h5>
7731<pre>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7732 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7733 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7734</pre>
7735
7736<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7737<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7738 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7739 operation like memcpy will either overflow a buffer that corresponds to
7740 an object, or b) to determine that a runtime check for overflow isn't
7741 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7742 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7743
7744<h5>Arguments:</h5>
7745<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7746 argument is a pointer to or into the <tt>object</tt>. The second argument
7747 is a boolean 0 or 1. This argument determines whether you want the
7748 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7749 1, variables are not allowed.</p>
7750
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7751<h5>Semantics:</h5>
7752<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7753 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7754 (depending on the <tt>type</tt> argument if the size cannot be determined
7755 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7756
7757</div>
7758
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7759<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7760<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7761<address>
7762 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7763 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7764 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7765 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]7766
7767 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7768 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7769 Last modified: $Date$
7770</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7771
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7772</body>
7773</html>