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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ff70fe40aa64ed260aaff5f77151c3c2fb39b75a / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]55 </ol>
56 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]88 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]89 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]97 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]127 </ol>
128 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]160 </ol>
161 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]169 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]174 </ol>
175 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]176 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]190 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]200 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 </ol>
212 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]241 </ol>
242 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]244 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <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]258 <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]259 </ol>
260 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <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]265 </ol>
266 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]300 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]326<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]361</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]363<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]366<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]373<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]374<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]379<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
380 LLVM infrastructure provides a verification pass that may be used to verify
381 that an LLVM module is well formed. This pass is automatically run by the
382 parser after parsing input assembly and by the optimizer before it outputs
383 bitcode. The violations pointed out by the verifier pass indicate bugs in
384 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]385
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]386</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]391<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]394<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]442%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]444</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]446<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]448<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]452</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]454<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]456<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%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]460%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]462</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
465 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]467<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
471 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]472 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474 <li>Unnamed temporaries are numbered sequentially</li>
475</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]476
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]477<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]478 demonstrating instructions, we will follow an instruction with a comment that
479 defines the type and name of value produced. Comments are shown in italic
480 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]482</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
484<!-- *********************************************************************** -->
485<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
486<!-- *********************************************************************** -->
487
488<!-- ======================================================================= -->
489<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
490</div>
491
492<div class="doc_text">
493
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]494<p>LLVM programs are composed of "Module"s, each of which is a translation unit
495 of the input programs. Each module consists of functions, global variables,
496 and symbol table entries. Modules may be combined together with the LLVM
497 linker, which merges function (and global variable) definitions, resolves
498 forward declarations, and merges symbol table entries. Here is an example of
499 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]501<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]502<pre>
503<i>; Declare the string constant as a global constant.</i>
504<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]505
506<i>; External declaration of the puts function</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]507<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508
509<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]510define i32 @main() { <i>; i32()* </i>
511 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]512 %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]513
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]514 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]515 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]516 <a href="#i_ret">ret</a> i32 0<br>}
517
518<i>; Named metadata</i>
519!1 = metadata !{i32 41}
520!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]521</pre>
522</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]524<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]525 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]527 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
528 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530<p>In general, a module is made up of a list of global values, where both
531 functions and global variables are global values. Global values are
532 represented by a pointer to a memory location (in this case, a pointer to an
533 array of char, and a pointer to a function), and have one of the
534 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]535
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="linkage">Linkage Types</a>
541</div>
542
543<div class="doc_text">
544
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]545<p>All Global Variables and Functions have one of the following types of
546 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]547
548<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
551 by objects in the current module. In particular, linking code into a
552 module with an private global value may cause the private to be renamed as
553 necessary to avoid collisions. Because the symbol is private to the
554 module, all references can be updated. This doesn't show up in any symbol
555 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]556
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]558 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
559 assembler and evaluated by the linker. Unlike normal strong symbols, they
560 are removed by the linker from the final linked image (executable or
561 dynamic library).</dd>
562
563 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
565 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
566 linker. The symbols are removed by the linker from the final linked image
567 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]636
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<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]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
796<div class="doc_code">
797<pre>
798%mytype = type { %mytype*, i32 }
799</pre>
800</div>
801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802<p>You may give a name to any <a href="#typesystem">type</a> except
803 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
804 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
806<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 and that you can therefore specify multiple names for the same type. This
808 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
809 uses structural typing, the name is not part of the type. When printing out
810 LLVM IR, the printer will pick <em>one name</em> to render all types of a
811 particular shape. This means that if you have code where two different
812 source types end up having the same LLVM type, that the dumper will sometimes
813 print the "wrong" or unexpected type. This is an important design point and
814 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]815
816</div>
817
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]818<!-- ======================================================================= -->
819<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]820 <a name="globalvars">Global Variables</a>
821</div>
822
823<div class="doc_text">
824
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]825<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826 instead of run-time. Global variables may optionally be initialized, may
827 have an explicit section to be placed in, and may have an optional explicit
828 alignment specified. A variable may be defined as "thread_local", which
829 means that it will not be shared by threads (each thread will have a
830 separated copy of the variable). A variable may be defined as a global
831 "constant," which indicates that the contents of the variable
832 will <b>never</b> be modified (enabling better optimization, allowing the
833 global data to be placed in the read-only section of an executable, etc).
834 Note that variables that need runtime initialization cannot be marked
835 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
838 constant, even if the final definition of the global is not. This capability
839 can be used to enable slightly better optimization of the program, but
840 requires the language definition to guarantee that optimizations based on the
841 'constantness' are valid for the translation units that do not include the
842 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]843
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]844<p>As SSA values, global variables define pointer values that are in scope
845 (i.e. they dominate) all basic blocks in the program. Global variables
846 always define a pointer to their "content" type because they describe a
847 region of memory, and all memory objects in LLVM are accessed through
848 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]850<p>A global variable may be declared to reside in a target-specific numbered
851 address space. For targets that support them, address spaces may affect how
852 optimizations are performed and/or what target instructions are used to
853 access the variable. The default address space is zero. The address space
854 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]855
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]856<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]857 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]858
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]859<p>An explicit alignment may be specified for a global, which must be a power
860 of 2. If not present, or if the alignment is set to zero, the alignment of
861 the global is set by the target to whatever it feels convenient. If an
862 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]863 alignment. Targets and optimizers are not allowed to over-align the global
864 if the global has an assigned section. In this case, the extra alignment
865 could be observable: for example, code could assume that the globals are
866 densely packed in their section and try to iterate over them as an array,
867 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]869<p>For example, the following defines a global in a numbered address space with
870 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]871
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]872<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]875</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]876</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]878</div>
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
883 <a name="functionstructure">Functions</a>
884</div>
885
886<div class="doc_text">
887
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]888<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]889 optional <a href="#linkage">linkage type</a>, an optional
890 <a href="#visibility">visibility style</a>, an optional
891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>, a return type, an optional
903 <a href="#paramattrs">parameter attribute</a> for the return type, a function
904 name, a possibly empty list of arguments, an optional alignment, and an
905 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]906
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]907<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908 (Control Flow Graph) for the function. Each basic block may optionally start
909 with a label (giving the basic block a symbol table entry), contains a list
910 of instructions, and ends with a <a href="#terminators">terminator</a>
911 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]913<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]914 executed on entrance to the function, and it is not allowed to have
915 predecessor basic blocks (i.e. there can not be any branches to the entry
916 block of a function). Because the block can have no predecessors, it also
917 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]919<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]921
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922<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]923 the alignment is set to zero, the alignment of the function is set by the
924 target to whatever it feels convenient. If an explicit alignment is
925 specified, the function is forced to have at least that much alignment. All
926 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]927
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]928<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]929<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]930<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]931define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
933 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
934 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
935 [<a href="#gc">gc</a>] { ... }
936</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]937</div>
938
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]939</div>
940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<!-- ======================================================================= -->
942<div class="doc_subsection">
943 <a name="aliasstructure">Aliases</a>
944</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]946<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947
948<p>Aliases act as "second name" for the aliasee value (which can be either
949 function, global variable, another alias or bitcast of global value). Aliases
950 may have an optional <a href="#linkage">linkage type</a>, and an
951 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]953<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]954<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]955<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]956@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]957</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]958</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
960</div>
961
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]962<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]963<div class="doc_subsection">
964 <a name="namedmetadatastructure">Named Metadata</a>
965</div>
966
967<div class="doc_text">
968
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
970 nodes</a> (but not metadata strings) and null are the only valid operands for
971 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
974<div class="doc_code">
975<pre>
976!1 = metadata !{metadata !"one"}
977!name = !{null, !1}
978</pre>
979</div>
980
981</div>
982
983<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]984<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]985
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986<div class="doc_text">
987
988<p>The return type and each parameter of a function type may have a set of
989 <i>parameter attributes</i> associated with them. Parameter attributes are
990 used to communicate additional information about the result or parameters of
991 a function. Parameter attributes are considered to be part of the function,
992 not of the function type, so functions with different parameter attributes
993 can have the same function type.</p>
994
995<p>Parameter attributes are simple keywords that follow the type specified. If
996 multiple parameter attributes are needed, they are space separated. For
997 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998
999<div class="doc_code">
1000<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1001declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1002declare i32 @atoi(i8 zeroext)
1003declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1004</pre>
1005</div>
1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1008 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>zeroext</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 zero-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>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be sign-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that this parameter or return value should be treated in a
1025 special target-dependent fashion during while emitting code for a function
1026 call or return (usually, by putting it in a register as opposed to memory,
1027 though some targets use it to distinguish between two different kinds of
1028 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that the pointer parameter should really be passed by value
1032 to the function. The attribute implies that a hidden copy of the pointee
1033 is made between the caller and the callee, so the callee is unable to
1034 modify the value in the callee. This attribute is only valid on LLVM
1035 pointer arguments. It is generally used to pass structs and arrays by
1036 value, but is also valid on pointers to scalars. The copy is considered
1037 to belong to the caller not the callee (for example,
1038 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1039 <tt>byval</tt> parameters). This is not a valid attribute for return
1040 values. The byval attribute also supports specifying an alignment with
1041 the align attribute. This has a target-specific effect on the code
1042 generator that usually indicates a desired alignment for the synthesized
1043 stack slot.</dd>
1044
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1045 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This indicates that the pointer parameter specifies the address of a
1047 structure that is the return value of the function in the source program.
1048 This pointer must be guaranteed by the caller to be valid: loads and
1049 stores to the structure may be assumed by the callee to not to trap. This
1050 may only be applied to the first parameter. This is not a valid attribute
1051 for return values. </dd>
1052
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1053 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1054 <dd>This indicates that pointer values
1055 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1056 value do not alias pointer values which are not <i>based</i> on it,
1057 ignoring certain "irrelevant" dependencies.
1058 For a call to the parent function, dependencies between memory
1059 references from before or after the call and from those during the call
1060 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1061 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1062 The caller shares the responsibility with the callee for ensuring that
1063 these requirements are met.
1064 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame^]1065 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1066<br>
1067 Note that this definition of <tt>noalias<tt> is intentionally
1068 similar to the definition of <tt>restrict<tt> in C99 for function
1069 arguments, thought it is slightly weaker.
1070<br>
1071 For function return values, C99's <tt>restrict</tt> is not meaningful,
1072 while LLVM's <tt>noalias</tt> is.
1073 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1075 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This indicates that the callee does not make any copies of the pointer
1077 that outlive the callee itself. This is not a valid attribute for return
1078 values.</dd>
1079
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1080 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1081 <dd>This indicates that the pointer parameter can be excised using the
1082 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1083 attribute for return values.</dd>
1084</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1085
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1086</div>
1087
1088<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1089<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1090 <a name="gc">Garbage Collector Names</a>
1091</div>
1092
1093<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1094
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1095<p>Each function may specify a garbage collector name, which is simply a
1096 string:</p>
1097
1098<div class="doc_code">
1099<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1100define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101</pre>
1102</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1103
1104<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1105 collector which will cause the compiler to alter its output in order to
1106 support the named garbage collection algorithm.</p>
1107
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1108</div>
1109
1110<!-- ======================================================================= -->
1111<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1112 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1113</div>
1114
1115<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1117<p>Function attributes are set to communicate additional information about a
1118 function. Function attributes are considered to be part of the function, not
1119 of the function type, so functions with different parameter attributes can
1120 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1122<p>Function attributes are simple keywords that follow the type specified. If
1123 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1124
1125<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1126<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1127define void @f() noinline { ... }
1128define void @f() alwaysinline { ... }
1129define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1130define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1131</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1132</div>
1133
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1134<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1135 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1136 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1137 the backend should forcibly align the stack pointer. Specify the
1138 desired alignment, which must be a power of two, in parentheses.
1139
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1140 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1141 <dd>This attribute indicates that the inliner should attempt to inline this
1142 function into callers whenever possible, ignoring any active inlining size
1143 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1144
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1145 <dt><tt><b>inlinehint</b></tt></dt>
1146 <dd>This attribute indicates that the source code contained a hint that inlining
1147 this function is desirable (such as the "inline" keyword in C/C++). It
1148 is just a hint; it imposes no requirements on the inliner.</dd>
1149
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1150 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1151 <dd>This attribute indicates that the inliner should never inline this
1152 function in any situation. This attribute may not be used together with
1153 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1154
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1155 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1156 <dd>This attribute suggests that optimization passes and code generator passes
1157 make choices that keep the code size of this function low, and otherwise
1158 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This function attribute indicates that the function never returns
1162 normally. This produces undefined behavior at runtime if the function
1163 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1164
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1165 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1166 <dd>This function attribute indicates that the function never returns with an
1167 unwind or exceptional control flow. If the function does unwind, its
1168 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1169
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function computes its result (or decides
1172 to unwind an exception) based strictly on its arguments, without
1173 dereferencing any pointer arguments or otherwise accessing any mutable
1174 state (e.g. memory, control registers, etc) visible to caller functions.
1175 It does not write through any pointer arguments
1176 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1177 changes any state visible to callers. This means that it cannot unwind
1178 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1179 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1180
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function does not write through any
1183 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1184 arguments) or otherwise modify any state (e.g. memory, control registers,
1185 etc) visible to caller functions. It may dereference pointer arguments
1186 and read state that may be set in the caller. A readonly function always
1187 returns the same value (or unwinds an exception identically) when called
1188 with the same set of arguments and global state. It cannot unwind an
1189 exception by calling the <tt>C++</tt> exception throwing methods, but may
1190 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1191
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function should emit a stack smashing
1194 protector. It is in the form of a "canary"&mdash;a random value placed on
1195 the stack before the local variables that's checked upon return from the
1196 function to see if it has been overwritten. A heuristic is used to
1197 determine if a function needs stack protectors or not.<br>
1198<br>
1199 If a function that has an <tt>ssp</tt> attribute is inlined into a
1200 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1201 function will have an <tt>ssp</tt> attribute.</dd>
1202
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute indicates that the function should <em>always</em> emit a
1205 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1206 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1207<br>
1208 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1209 function that doesn't have an <tt>sspreq</tt> attribute or which has
1210 an <tt>ssp</tt> attribute, then the resulting function will have
1211 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1213 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1214 <dd>This attribute indicates that the code generator should not use a red
1215 zone, even if the target-specific ABI normally permits it.</dd>
1216
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1217 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1218 <dd>This attributes disables implicit floating point instructions.</dd>
1219
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1220 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1221 <dd>This attribute disables prologue / epilogue emission for the function.
1222 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1223</dl>
1224
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1225</div>
1226
1227<!-- ======================================================================= -->
1228<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1229 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1230</div>
1231
1232<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1233
1234<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1235 the GCC "file scope inline asm" blocks. These blocks are internally
1236 concatenated by LLVM and treated as a single unit, but may be separated in
1237 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1238
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1239<div class="doc_code">
1240<pre>
1241module asm "inline asm code goes here"
1242module asm "more can go here"
1243</pre>
1244</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1245
1246<p>The strings can contain any character by escaping non-printable characters.
1247 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]1248 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1249
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1250<p>The inline asm code is simply printed to the machine code .s file when
1251 assembly code is generated.</p>
1252
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1253</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1254
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1255<!-- ======================================================================= -->
1256<div class="doc_subsection">
1257 <a name="datalayout">Data Layout</a>
1258</div>
1259
1260<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1262<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263 data is to be laid out in memory. The syntax for the data layout is
1264 simply:</p>
1265
1266<div class="doc_code">
1267<pre>
1268target datalayout = "<i>layout specification</i>"
1269</pre>
1270</div>
1271
1272<p>The <i>layout specification</i> consists of a list of specifications
1273 separated by the minus sign character ('-'). Each specification starts with
1274 a letter and may include other information after the letter to define some
1275 aspect of the data layout. The specifications accepted are as follows:</p>
1276
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1277<dl>
1278 <dt><tt>E</tt></dt>
1279 <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]1280 bits with the most significance have the lowest address location.</dd>
1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1283 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1284 the bits with the least significance have the lowest address
1285 location.</dd>
1286
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1287 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1288 <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]1289 <i>preferred</i> alignments. All sizes are in bits. Specifying
1290 the <i>pref</i> alignment is optional. If omitted, the
1291 preceding <tt>:</tt> should be omitted too.</dd>
1292
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1296
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1297 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1298 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1299 <i>size</i>.</dd>
1300
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1301 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1302 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1303 <i>size</i>. Only values of <i>size</i> that are supported by the target
1304 will work. 32 (float) and 64 (double) are supported on all targets;
1305 80 or 128 (different flavors of long double) are also supported on some
1306 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1308 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1309 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1310 <i>size</i>.</dd>
1311
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1312 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1313 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1314 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1315
1316 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1317 <dd>This specifies a set of native integer widths for the target CPU
1318 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1319 "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]1320 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1321 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1323
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1324<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1325 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1326 specifications in the <tt>datalayout</tt> keyword. The default specifications
1327 are given in this list:</p>
1328
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329<ul>
1330 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1331 <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]1332 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1333 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1334 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1335 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1336 <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]1337 alignment of 64-bits</li>
1338 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1339 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1340 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1341 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1342 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1343 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1344</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>When LLVM is determining the alignment for a given type, it uses the
1347 following rules:</p>
1348
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1349<ol>
1350 <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]1351 specification is used.</li>
1352
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1353 <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]1354 smallest integer type that is larger than the bitwidth of the sought type
1355 is used. If none of the specifications are larger than the bitwidth then
1356 the the largest integer type is used. For example, given the default
1357 specifications above, the i7 type will use the alignment of i8 (next
1358 largest) while both i65 and i256 will use the alignment of i64 (largest
1359 specified).</li>
1360
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361 <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]1362 largest vector type that is smaller than the sought vector type will be
1363 used as a fall back. This happens because &lt;128 x double&gt; can be
1364 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1365</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1366
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1367</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1368
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1369<!-- ======================================================================= -->
1370<div class="doc_subsection">
1371 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1372</div>
1373
1374<div class="doc_text">
1375
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1376<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1377with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1378is undefined. Pointer values are associated with address ranges
1379according to the following rules:</p>
1380
1381<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1382 <li>A pointer value is associated with the addresses associated with
1383 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1384 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1385 range of the variable's storage.</li>
1386 <li>The result value of an allocation instruction is associated with
1387 the address range of the allocated storage.</li>
1388 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1389 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1390 <li>An integer constant other than zero or a pointer value returned
1391 from a function not defined within LLVM may be associated with address
1392 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1393 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1394 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1395</ul>
1396
1397<p>A pointer value is <i>based</i> on another pointer value according
1398 to the following rules:</p>
1399
1400<ul>
1401 <li>A pointer value formed from a
1402 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1403 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1404 <li>The result value of a
1405 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1406 of the <tt>bitcast</tt>.</li>
1407 <li>A pointer value formed by an
1408 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1409 pointer values that contribute (directly or indirectly) to the
1410 computation of the pointer's value.</li>
1411 <li>The "<i>based</i> on" relationship is transitive.</li>
1412</ul>
1413
1414<p>Note that this definition of <i>"based"</i> is intentionally
1415 similar to the definition of <i>"based"</i> in C99, though it is
1416 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1419<tt><a href="#i_load">load</a></tt> merely indicates the size and
1420alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1421interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1422<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1423and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1424
1425<p>Consequently, type-based alias analysis, aka TBAA, aka
1426<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1427LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1428additional information which specialized optimization passes may use
1429to implement type-based alias analysis.</p>
1430
1431</div>
1432
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1433<!-- ======================================================================= -->
1434<div class="doc_subsection">
1435 <a name="volatile">Volatile Memory Accesses</a>
1436</div>
1437
1438<div class="doc_text">
1439
1440<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1441href="#i_store"><tt>store</tt></a>s, and <a
1442href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1443The optimizers must not change the number of volatile operations or change their
1444order of execution relative to other volatile operations. The optimizers
1445<i>may</i> change the order of volatile operations relative to non-volatile
1446operations. This is not Java's "volatile" and has no cross-thread
1447synchronization behavior.</p>
1448
1449</div>
1450
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1451<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1452<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1453<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1454
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1455<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1457<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1458 intermediate representation. Being typed enables a number of optimizations
1459 to be performed on the intermediate representation directly, without having
1460 to do extra analyses on the side before the transformation. A strong type
1461 system makes it easier to read the generated code and enables novel analyses
1462 and transformations that are not feasible to perform on normal three address
1463 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1464
1465</div>
1466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1467<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1470
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1471<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1472
1473<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1474
1475<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1476 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1477 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1479 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1480 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1481 </tr>
1482 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483 <td><a href="#t_floating">floating point</a></td>
1484 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1485 </tr>
1486 <tr>
1487 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488 <td><a href="#t_integer">integer</a>,
1489 <a href="#t_floating">floating point</a>,
1490 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1491 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1492 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1493 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1494 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_label">label</a>,
1496 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1497 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1498 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499 <tr>
1500 <td><a href="#t_primitive">primitive</a></td>
1501 <td><a href="#t_label">label</a>,
1502 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1503 <a href="#t_floating">floating point</a>,
1504 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1505 </tr>
1506 <tr>
1507 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1508 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 <a href="#t_function">function</a>,
1510 <a href="#t_pointer">pointer</a>,
1511 <a href="#t_struct">structure</a>,
1512 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1513 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1514 <a href="#t_vector">vector</a>,
1515 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1516 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1518 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1519</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1521<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1522 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1523 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1524
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1525</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1527<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1528<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1529
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1530<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1531
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1532<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1534
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1535</div>
1536
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1537<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1538<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1539
1540<div class="doc_text">
1541
1542<h5>Overview:</h5>
1543<p>The integer type is a very simple type that simply specifies an arbitrary
1544 bit width for the integer type desired. Any bit width from 1 bit to
1545 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1546
1547<h5>Syntax:</h5>
1548<pre>
1549 iN
1550</pre>
1551
1552<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1553 value.</p>
1554
1555<h5>Examples:</h5>
1556<table class="layout">
1557 <tr class="layout">
1558 <td class="left"><tt>i1</tt></td>
1559 <td class="left">a single-bit integer.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>i32</tt></td>
1563 <td class="left">a 32-bit integer.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>i1942652</tt></td>
1567 <td class="left">a really big integer of over 1 million bits.</td>
1568 </tr>
1569</table>
1570
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1571</div>
1572
1573<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1574<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1575
1576<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1577
1578<table>
1579 <tbody>
1580 <tr><th>Type</th><th>Description</th></tr>
1581 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1582 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1583 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1584 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1585 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1586 </tbody>
1587</table>
1588
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1589</div>
1590
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1593
1594<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1595
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1596<h5>Overview:</h5>
1597<p>The void type does not represent any value and has no size.</p>
1598
1599<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1600<pre>
1601 void
1602</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1603
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1604</div>
1605
1606<!-- _______________________________________________________________________ -->
1607<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1608
1609<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1611<h5>Overview:</h5>
1612<p>The label type represents code labels.</p>
1613
1614<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1615<pre>
1616 label
1617</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1618
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1619</div>
1620
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1621<!-- _______________________________________________________________________ -->
1622<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1623
1624<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1625
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1626<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1627<p>The metadata type represents embedded metadata. No derived types may be
1628 created from metadata except for <a href="#t_function">function</a>
1629 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1630
1631<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1632<pre>
1633 metadata
1634</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1635
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1636</div>
1637
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1638
1639<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1640<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644<p>The real power in LLVM comes from the derived types in the system. This is
1645 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1646 useful types. Each of these types contain one or more element types which
1647 may be a primitive type, or another derived type. For example, it is
1648 possible to have a two dimensional array, using an array as the element type
1649 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1650
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1651
1652</div>
1653
1654<!-- _______________________________________________________________________ -->
1655<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1656
1657<div class="doc_text">
1658
1659<p>Aggregate Types are a subset of derived types that can contain multiple
1660 member types. <a href="#t_array">Arrays</a>,
1661 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1662 <a href="#t_union">unions</a> are aggregate types.</p>
1663
1664</div>
1665
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1666</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1667
1668<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1669<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1670
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1671<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1673<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1674<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1675 sequentially in memory. The array type requires a size (number of elements)
1676 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1677
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1678<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1679<pre>
1680 [&lt;# elements&gt; x &lt;elementtype&gt;]
1681</pre>
1682
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1683<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1684 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1685
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1686<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1687<table class="layout">
1688 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1689 <td class="left"><tt>[40 x i32]</tt></td>
1690 <td class="left">Array of 40 32-bit integer values.</td>
1691 </tr>
1692 <tr class="layout">
1693 <td class="left"><tt>[41 x i32]</tt></td>
1694 <td class="left">Array of 41 32-bit integer values.</td>
1695 </tr>
1696 <tr class="layout">
1697 <td class="left"><tt>[4 x i8]</tt></td>
1698 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1699 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1701<p>Here are some examples of multidimensional arrays:</p>
1702<table class="layout">
1703 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1704 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1705 <td class="left">3x4 array of 32-bit integer values.</td>
1706 </tr>
1707 <tr class="layout">
1708 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1709 <td class="left">12x10 array of single precision floating point values.</td>
1710 </tr>
1711 <tr class="layout">
1712 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1713 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1714 </tr>
1715</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1716
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1717<p>There is no restriction on indexing beyond the end of the array implied by
1718 a static type (though there are restrictions on indexing beyond the bounds
1719 of an allocated object in some cases). This means that single-dimension
1720 'variable sized array' addressing can be implemented in LLVM with a zero
1721 length array type. An implementation of 'pascal style arrays' in LLVM could
1722 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1723
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1724</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1726<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1727<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1728
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1732<p>The function type can be thought of as a function signature. It consists of
1733 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]1734 function type is a scalar type, a void type, a struct type, or a union
1735 type. If the return type is a struct type then all struct elements must be
1736 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1739<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1740 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1741</pre>
1742
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1743<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]1744 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1745 which indicates that the function takes a variable number of arguments.
1746 Variable argument functions can access their arguments with
1747 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1748 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1749 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1752<table class="layout">
1753 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1754 <td class="left"><tt>i32 (i32)</tt></td>
1755 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1756 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1757 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1758 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1759 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1760 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1761 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1762 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1763 </td>
1764 </tr><tr class="layout">
1765 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1766 <td class="left">A vararg function that takes at least one
1767 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1768 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1769 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1770 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1771 </tr><tr class="layout">
1772 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1773 <td class="left">A function taking an <tt>i32</tt>, returning a
1774 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1775 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1776 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1777</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1779</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1782<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1784<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1787<p>The structure type is used to represent a collection of data members together
1788 in memory. The packing of the field types is defined to match the ABI of the
1789 underlying processor. The elements of a structure may be any type that has a
1790 size.</p>
1791
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1792<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1793 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1794 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1795 Structures in registers are accessed using the
1796 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1797 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1799<pre>
1800 { &lt;type list&gt; }
1801</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1804<table class="layout">
1805 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1806 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1807 <td class="left">A triple of three <tt>i32</tt> values</td>
1808 </tr><tr class="layout">
1809 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1810 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1811 second element is a <a href="#t_pointer">pointer</a> to a
1812 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1813 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1814 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1815</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1817</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1820<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1821</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1825<h5>Overview:</h5>
1826<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827 together in memory. There is no padding between fields. Further, the
1828 alignment of a packed structure is 1 byte. The elements of a packed
1829 structure may be any type that has a size.</p>
1830
1831<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1832 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1833 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1834
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1835<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1836<pre>
1837 &lt; { &lt;type list&gt; } &gt;
1838</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1839
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1840<h5>Examples:</h5>
1841<table class="layout">
1842 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1843 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1844 <td class="left">A triple of three <tt>i32</tt> values</td>
1845 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1846 <td class="left">
1847<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1848 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1849 second element is a <a href="#t_pointer">pointer</a> to a
1850 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1851 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1852 </tr>
1853</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1854
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855</div>
1856
1857<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1858<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1859
1860<div class="doc_text">
1861
1862<h5>Overview:</h5>
1863<p>A union type describes an object with size and alignment suitable for
1864 an object of any one of a given set of types (also known as an "untagged"
1865 union). It is similar in concept and usage to a
1866 <a href="#t_struct">struct</a>, except that all members of the union
1867 have an offset of zero. The elements of a union may be any type that has a
1868 size. Unions must have at least one member - empty unions are not allowed.
1869 </p>
1870
1871<p>The size of the union as a whole will be the size of its largest member,
1872 and the alignment requirements of the union as a whole will be the largest
1873 alignment requirement of any member.</p>
1874
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1875<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]1876 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1877 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1878 Since all members are at offset zero, the getelementptr instruction does
1879 not affect the address, only the type of the resulting pointer.</p>
1880
1881<h5>Syntax:</h5>
1882<pre>
1883 union { &lt;type list&gt; }
1884</pre>
1885
1886<h5>Examples:</h5>
1887<table class="layout">
1888 <tr class="layout">
1889 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1890 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1891 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1892 </tr><tr class="layout">
1893 <td class="left">
1894 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1895 <td class="left">A union, where the first element is a <tt>float</tt> and the
1896 second element is a <a href="#t_pointer">pointer</a> to a
1897 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1898 an <tt>i32</tt>.</td>
1899 </tr>
1900</table>
1901
1902</div>
1903
1904<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1906
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1907<div class="doc_text">
1908
1909<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1910<p>The pointer type is used to specify memory locations.
1911 Pointers are commonly used to reference objects in memory.</p>
1912
1913<p>Pointer types may have an optional address space attribute defining the
1914 numbered address space where the pointed-to object resides. The default
1915 address space is number zero. The semantics of non-zero address
1916 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1917
1918<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1919 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1920
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1921<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1922<pre>
1923 &lt;type&gt; *
1924</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1925
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1926<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1927<table class="layout">
1928 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1929 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1930 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1931 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1932 </tr>
1933 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1934 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1935 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1936 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1937 <tt>i32</tt>.</td>
1938 </tr>
1939 <tr class="layout">
1940 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1941 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1942 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1943 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1944</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1945
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1946</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1947
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1948<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1949<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1951<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1952
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1954<p>A vector type is a simple derived type that represents a vector of elements.
1955 Vector types are used when multiple primitive data are operated in parallel
1956 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1957 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1958 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1959
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1960<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1961<pre>
1962 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1963</pre>
1964
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1965<p>The number of elements is a constant integer value; elementtype may be any
1966 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1968<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1969<table class="layout">
1970 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1971 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1972 <td class="left">Vector of 4 32-bit integer values.</td>
1973 </tr>
1974 <tr class="layout">
1975 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1976 <td class="left">Vector of 8 32-bit floating-point values.</td>
1977 </tr>
1978 <tr class="layout">
1979 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1980 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1981 </tr>
1982</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1983
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1984</div>
1985
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1986<!-- _______________________________________________________________________ -->
1987<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1988<div class="doc_text">
1989
1990<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1991<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1992 corresponds (for example) to the C notion of a forward declared structure
1993 type. In LLVM, opaque types can eventually be resolved to any type (not just
1994 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1995
1996<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1997<pre>
1998 opaque
1999</pre>
2000
2001<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2004 <td class="left"><tt>opaque</tt></td>
2005 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2006 </tr>
2007</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2008
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2009</div>
2010
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2011<!-- ======================================================================= -->
2012<div class="doc_subsection">
2013 <a name="t_uprefs">Type Up-references</a>
2014</div>
2015
2016<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2017
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2018<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2019<p>An "up reference" allows you to refer to a lexically enclosing type without
2020 requiring it to have a name. For instance, a structure declaration may
2021 contain a pointer to any of the types it is lexically a member of. Example
2022 of up references (with their equivalent as named type declarations)
2023 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2024
2025<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2026 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2027 { \2 }* %y = type { %y }*
2028 \1* %z = type %z*
2029</pre>
2030
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2031<p>An up reference is needed by the asmprinter for printing out cyclic types
2032 when there is no declared name for a type in the cycle. Because the
2033 asmprinter does not want to print out an infinite type string, it needs a
2034 syntax to handle recursive types that have no names (all names are optional
2035 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2036
2037<h5>Syntax:</h5>
2038<pre>
2039 \&lt;level&gt;
2040</pre>
2041
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042<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]2043
2044<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2045<table class="layout">
2046 <tr class="layout">
2047 <td class="left"><tt>\1*</tt></td>
2048 <td class="left">Self-referential pointer.</td>
2049 </tr>
2050 <tr class="layout">
2051 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2052 <td class="left">Recursive structure where the upref refers to the out-most
2053 structure.</td>
2054 </tr>
2055</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2056
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2057</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2058
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2059<!-- *********************************************************************** -->
2060<div class="doc_section"> <a name="constants">Constants</a> </div>
2061<!-- *********************************************************************** -->
2062
2063<div class="doc_text">
2064
2065<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2066 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2067
2068</div>
2069
2070<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2071<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2072
2073<div class="doc_text">
2074
2075<dl>
2076 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2077 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2078 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2079
2080 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2081 <dd>Standard integers (such as '4') are constants of
2082 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2083 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2084
2085 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2086 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2087 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2088 notation (see below). The assembler requires the exact decimal value of a
2089 floating-point constant. For example, the assembler accepts 1.25 but
2090 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2091 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2092
2093 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2094 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2095 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2096</dl>
2097
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2098<p>The one non-intuitive notation for constants is the hexadecimal form of
2099 floating point constants. For example, the form '<tt>double
2100 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2101 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2102 constants are required (and the only time that they are generated by the
2103 disassembler) is when a floating point constant must be emitted but it cannot
2104 be represented as a decimal floating point number in a reasonable number of
2105 digits. For example, NaN's, infinities, and other special values are
2106 represented in their IEEE hexadecimal format so that assembly and disassembly
2107 do not cause any bits to change in the constants.</p>
2108
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2109<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110 represented using the 16-digit form shown above (which matches the IEEE754
2111 representation for double); float values must, however, be exactly
2112 representable as IEE754 single precision. Hexadecimal format is always used
2113 for long double, and there are three forms of long double. The 80-bit format
2114 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2115 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2116 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2117 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2118 currently supported target uses this format. Long doubles will only work if
2119 they match the long double format on your target. All hexadecimal formats
2120 are big-endian (sign bit at the left).</p>
2121
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2122</div>
2123
2124<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2125<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2126<a name="aggregateconstants"></a> <!-- old anchor -->
2127<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2128</div>
2129
2130<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2131
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2132<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2133 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2134
2135<dl>
2136 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2138 type definitions (a comma separated list of elements, surrounded by braces
2139 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2140 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2141 Structure constants must have <a href="#t_struct">structure type</a>, and
2142 the number and types of elements must match those specified by the
2143 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2144
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2145 <dt><b>Union constants</b></dt>
2146 <dd>Union constants are represented with notation similar to a structure with
2147 a single element - that is, a single typed element surrounded
2148 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2149 <a href="#t_union">union type</a> can be initialized with a single-element
2150 struct as long as the type of the struct element matches the type of
2151 one of the union members.</dd>
2152
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2153 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2154 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2155 definitions (a comma separated list of elements, surrounded by square
2156 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2157 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2158 the number and types of elements must match those specified by the
2159 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2160
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2161 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2162 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2163 definitions (a comma separated list of elements, surrounded by
2164 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2165 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2166 have <a href="#t_vector">vector type</a>, and the number and types of
2167 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2168
2169 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2170 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2171 value to zero of <em>any</em> type, including scalar and
2172 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2173 This is often used to avoid having to print large zero initializers
2174 (e.g. for large arrays) and is always exactly equivalent to using explicit
2175 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2176
2177 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2178 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2179 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2180 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2181 be interpreted as part of the instruction stream, metadata is a place to
2182 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2183</dl>
2184
2185</div>
2186
2187<!-- ======================================================================= -->
2188<div class="doc_subsection">
2189 <a name="globalconstants">Global Variable and Function Addresses</a>
2190</div>
2191
2192<div class="doc_text">
2193
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2194<p>The addresses of <a href="#globalvars">global variables</a>
2195 and <a href="#functionstructure">functions</a> are always implicitly valid
2196 (link-time) constants. These constants are explicitly referenced when
2197 the <a href="#identifiers">identifier for the global</a> is used and always
2198 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2199 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2200
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2201<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2202<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2203@X = global i32 17
2204@Y = global i32 42
2205@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2206</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2207</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2208
2209</div>
2210
2211<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2212<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2213<div class="doc_text">
2214
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2215<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]2216 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2217 Undefined values may be of any type (other than label or void) and be used
2218 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2219
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2220<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2221 program is well defined no matter what value is used. This gives the
2222 compiler more freedom to optimize. Here are some examples of (potentially
2223 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2224
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2225
2226<div class="doc_code">
2227<pre>
2228 %A = add %X, undef
2229 %B = sub %X, undef
2230 %C = xor %X, undef
2231Safe:
2232 %A = undef
2233 %B = undef
2234 %C = undef
2235</pre>
2236</div>
2237
2238<p>This is safe because all of the output bits are affected by the undef bits.
2239Any output bit can have a zero or one depending on the input bits.</p>
2240
2241<div class="doc_code">
2242<pre>
2243 %A = or %X, undef
2244 %B = and %X, undef
2245Safe:
2246 %A = -1
2247 %B = 0
2248Unsafe:
2249 %A = undef
2250 %B = undef
2251</pre>
2252</div>
2253
2254<p>These logical operations have bits that are not always affected by the input.
2255For example, if "%X" has a zero bit, then the output of the 'and' operation will
2256always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2257such, 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]2258However, it is safe to assume that all bits of the undef could be 0, and
2259optimize the and to 0. Likewise, it is safe to assume that all the bits of
2260the 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]2261-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2262
2263<div class="doc_code">
2264<pre>
2265 %A = select undef, %X, %Y
2266 %B = select undef, 42, %Y
2267 %C = select %X, %Y, undef
2268Safe:
2269 %A = %X (or %Y)
2270 %B = 42 (or %Y)
2271 %C = %Y
2272Unsafe:
2273 %A = undef
2274 %B = undef
2275 %C = undef
2276</pre>
2277</div>
2278
2279<p>This set of examples show that undefined select (and conditional branch)
2280conditions can go "either way" but they have to come from one of the two
2281operands. In the %A example, if %X and %Y were both known to have a clear low
2282bit, then %A would have to have a cleared low bit. However, in the %C example,
2283the optimizer is allowed to assume that the undef operand could be the same as
2284%Y, allowing the whole select to be eliminated.</p>
2285
2286
2287<div class="doc_code">
2288<pre>
2289 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2290
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2291 %B = undef
2292 %C = xor %B, %B
2293
2294 %D = undef
2295 %E = icmp lt %D, 4
2296 %F = icmp gte %D, 4
2297
2298Safe:
2299 %A = undef
2300 %B = undef
2301 %C = undef
2302 %D = undef
2303 %E = undef
2304 %F = undef
2305</pre>
2306</div>
2307
2308<p>This example points out that two undef operands are not necessarily the same.
2309This can be surprising to people (and also matches C semantics) where they
2310assume that "X^X" is always zero, even if X is undef. This isn't true for a
2311number of reasons, but the short answer is that an undef "variable" can
2312arbitrarily change its value over its "live range". This is true because the
2313"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2314logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2315so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2316to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2317would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2318
2319<div class="doc_code">
2320<pre>
2321 %A = fdiv undef, %X
2322 %B = fdiv %X, undef
2323Safe:
2324 %A = undef
2325b: unreachable
2326</pre>
2327</div>
2328
2329<p>These examples show the crucial difference between an <em>undefined
2330value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2331allowed to have an arbitrary bit-pattern. This means that the %A operation
2332can be constant folded to undef because the undef could be an SNaN, and fdiv is
2333not (currently) defined on SNaN's. However, in the second example, we can make
2334a more aggressive assumption: because the undef is allowed to be an arbitrary
2335value, 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]2336has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2337does not execute at all. This allows us to delete the divide and all code after
2338it: since the undefined operation "can't happen", the optimizer can assume that
2339it occurs in dead code.
2340</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2341
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2342<div class="doc_code">
2343<pre>
2344a: store undef -> %X
2345b: store %X -> undef
2346Safe:
2347a: &lt;deleted&gt;
2348b: unreachable
2349</pre>
2350</div>
2351
2352<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2353can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2354overwritten with bits that happen to match what was already there. However, a
2355store "to" an undefined location could clobber arbitrary memory, therefore, it
2356has undefined behavior.</p>
2357
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2358</div>
2359
2360<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2361<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2362<div class="doc_text">
2363
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2364<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2365 instead of representing an unspecified bit pattern, they represent the
2366 fact that an instruction or constant expression which cannot evoke side
2367 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2368 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2369
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2370<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2371 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2372 <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]2373
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2374<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2375
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2376<p>
2377<ul>
2378<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2379 their operands.</li>
2380
2381<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2382 to their dynamic predecessor basic block.</li>
2383
2384<li>Function arguments depend on the corresponding actual argument values in
2385 the dynamic callers of their functions.</li>
2386
2387<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2388 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2389 control back to them.</li>
2390
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2391<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2392 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2393 or exception-throwing call instructions that dynamically transfer control
2394 back to them.</li>
2395
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2396<li>Non-volatile loads and stores depend on the most recent stores to all of the
2397 referenced memory addresses, following the order in the IR
2398 (including loads and stores implied by intrinsics such as
2399 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2400
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2401<!-- TODO: In the case of multiple threads, this only applies if the store
2402 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2403
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2404<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2405
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2406<li>An instruction with externally visible side effects depends on the most
2407 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame^]2408 the order in the IR. (This includes
2409 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2410
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2411<li>An instruction <i>control-depends</i> on a
2412 <a href="#terminators">terminator instruction</a>
2413 if the terminator instruction has multiple successors and the instruction
2414 is always executed when control transfers to one of the successors, and
2415 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2416
2417<li>Dependence is transitive.</li>
2418
2419</ul>
2420</p>
2421
2422<p>Whenever a trap value is generated, all values which depend on it evaluate
2423 to trap. If they have side effects, the evoke their side effects as if each
2424 operand with a trap value were undef. If they have externally-visible side
2425 effects, the behavior is undefined.</p>
2426
2427<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2428
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2429<div class="doc_code">
2430<pre>
2431entry:
2432 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2433 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2434 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2435 store i32 0, i32* %trap_yet_again ; undefined behavior
2436
2437 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2438 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2439
2440 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2441
2442 %narrowaddr = bitcast i32* @g to i16*
2443 %wideaddr = bitcast i32* @g to i64*
2444 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2445 %trap4 = load i64* %widaddr ; Returns a trap value.
2446
2447 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2448 %br i1 %cmp, %true, %end ; Branch to either destination.
2449
2450true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2451 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2452 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2453 br label %end
2454
2455end:
2456 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2457 ; Both edges into this PHI are
2458 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2459 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2460
2461 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2462 ; so this is defined (ignoring earlier
2463 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2464</pre>
2465</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2466
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2467</div>
2468
2469<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2470<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2471 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2472<div class="doc_text">
2473
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2474<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2475
2476<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2477 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2478 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2479
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2480<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2481 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2482 against null. Pointer equality tests between labels addresses is undefined
2483 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2484 equal to the null pointer. This may also be passed around as an opaque
2485 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2486 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2487 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2488
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2489<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2490 using the value as the operand to an inline assembly, but that is target
2491 specific.
2492 </p>
2493
2494</div>
2495
2496
2497<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2498<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2499</div>
2500
2501<div class="doc_text">
2502
2503<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2504 to be used as constants. Constant expressions may be of
2505 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2506 operation that does not have side effects (e.g. load and call are not
2507 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2508
2509<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2510 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2511 <dd>Truncate a constant to another type. The bit size of CST must be larger
2512 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2513
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2514 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2515 <dd>Zero extend a constant to another type. The bit size of CST must be
2516 smaller or equal to the bit size of TYPE. Both types must be
2517 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2518
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520 <dd>Sign extend a constant to another type. The bit size of CST must be
2521 smaller or equal to the bit size of TYPE. Both types must be
2522 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2523
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2525 <dd>Truncate a floating point constant to another floating point type. The
2526 size of CST must be larger than the size of TYPE. Both types must be
2527 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2528
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2529 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2530 <dd>Floating point extend a constant to another type. The size of CST must be
2531 smaller or equal to the size of TYPE. Both types must be floating
2532 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2533
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2534 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2535 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 constant. TYPE must be a scalar or vector integer type. CST must be of
2537 scalar or vector floating point type. Both CST and TYPE must be scalars,
2538 or vectors of the same number of elements. If the value won't fit in the
2539 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2540
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2541 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2542 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2543 constant. TYPE must be a scalar or vector integer type. CST must be of
2544 scalar or vector floating point type. Both CST and TYPE must be scalars,
2545 or vectors of the same number of elements. If the value won't fit in the
2546 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2547
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2549 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550 constant. TYPE must be a scalar or vector floating point type. CST must be
2551 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2552 vectors of the same number of elements. If the value won't fit in the
2553 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2554
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2555 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2556 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557 constant. TYPE must be a scalar or vector floating point type. CST must be
2558 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2559 vectors of the same number of elements. If the value won't fit in the
2560 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2561
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2562 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2563 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2564 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2565 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2566 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2567
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2568 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2569 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2570 type. CST must be of integer type. The CST value is zero extended,
2571 truncated, or unchanged to make it fit in a pointer size. This one is
2572 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2573
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2574 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2575 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2576 are the same as those for the <a href="#i_bitcast">bitcast
2577 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2578
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2579 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2580 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2581 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2582 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2583 instruction, the index list may have zero or more indexes, which are
2584 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2585
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2586 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2587 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2588
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2589 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2590 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2591
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2592 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2593 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2594
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2595 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2596 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2597 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2598
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2599 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2600 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2601 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2602
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2603 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2604 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2605 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2606
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2607 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2608 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2609 constants. The index list is interpreted in a similar manner as indices in
2610 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2611 index value must be specified.</dd>
2612
2613 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2614 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2615 constants. The index list is interpreted in a similar manner as indices in
2616 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2617 index value must be specified.</dd>
2618
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2619 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2620 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2621 be any of the <a href="#binaryops">binary</a>
2622 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2623 on operands are the same as those for the corresponding instruction
2624 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2625</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2626
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2627</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2628
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2629<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2630<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2631<!-- *********************************************************************** -->
2632
2633<!-- ======================================================================= -->
2634<div class="doc_subsection">
2635<a name="inlineasm">Inline Assembler Expressions</a>
2636</div>
2637
2638<div class="doc_text">
2639
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2640<p>LLVM supports inline assembler expressions (as opposed
2641 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2642 a special value. This value represents the inline assembler as a string
2643 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2644 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2645 expression has side effects, and a flag indicating whether the function
2646 containing the asm needs to align its stack conservatively. An example
2647 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2648
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2649<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2650<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2651i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2652</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2653</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2654
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2655<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2656 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2657 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2658
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2659<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2660<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2661%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]2662</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2663</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2664
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2665<p>Inline asms with side effects not visible in the constraint list must be
2666 marked as having side effects. This is done through the use of the
2667 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2668
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2669<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2670<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2671call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2672</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2673</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2674
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2675<p>In some cases inline asms will contain code that will not work unless the
2676 stack is aligned in some way, such as calls or SSE instructions on x86,
2677 yet will not contain code that does that alignment within the asm.
2678 The compiler should make conservative assumptions about what the asm might
2679 contain and should generate its usual stack alignment code in the prologue
2680 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2681
2682<div class="doc_code">
2683<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2684call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2685</pre>
2686</div>
2687
2688<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2689 first.</p>
2690
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2691<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692 documented here. Constraints on what can be done (e.g. duplication, moving,
2693 etc need to be documented). This is probably best done by reference to
2694 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2695</div>
2696
2697<div class="doc_subsubsection">
2698<a name="inlineasm_md">Inline Asm Metadata</a>
2699</div>
2700
2701<div class="doc_text">
2702
2703<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2704 attached to it that contains a constant integer. If present, the code
2705 generator will use the integer as the location cookie value when report
2706 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2707 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2708 source code that produced it. For example:</p>
2709
2710<div class="doc_code">
2711<pre>
2712call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2713...
2714!42 = !{ i32 1234567 }
2715</pre>
2716</div>
2717
2718<p>It is up to the front-end to make sense of the magic numbers it places in the
2719 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2720
2721</div>
2722
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2723<!-- ======================================================================= -->
2724<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2725 Strings</a>
2726</div>
2727
2728<div class="doc_text">
2729
2730<p>LLVM IR allows metadata to be attached to instructions in the program that
2731 can convey extra information about the code to the optimizers and code
2732 generator. One example application of metadata is source-level debug
2733 information. There are two metadata primitives: strings and nodes. All
2734 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2735 preceding exclamation point ('<tt>!</tt>').</p>
2736
2737<p>A metadata string is a string surrounded by double quotes. It can contain
2738 any character by escaping non-printable characters with "\xx" where "xx" is
2739 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2740
2741<p>Metadata nodes are represented with notation similar to structure constants
2742 (a comma separated list of elements, surrounded by braces and preceded by an
2743 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2744 10}</tt>". Metadata nodes can have any values as their operand.</p>
2745
2746<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2747 metadata nodes, which can be looked up in the module symbol table. For
2748 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2749
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2750<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2751 function is using two metadata arguments.
2752
2753 <div class="doc_code">
2754 <pre>
2755 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2756 </pre>
2757 </div></p>
2758
2759<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2760 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2761
2762 <div class="doc_code">
2763 <pre>
2764 %indvar.next = add i64 %indvar, 1, !dbg !21
2765 </pre>
2766 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2767</div>
2768
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2769
2770<!-- *********************************************************************** -->
2771<div class="doc_section">
2772 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2773</div>
2774<!-- *********************************************************************** -->
2775
2776<p>LLVM has a number of "magic" global variables that contain data that affect
2777code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2778of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2779section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2780by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2781
2782<!-- ======================================================================= -->
2783<div class="doc_subsection">
2784<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2785</div>
2786
2787<div class="doc_text">
2788
2789<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2790href="#linkage_appending">appending linkage</a>. This array contains a list of
2791pointers to global variables and functions which may optionally have a pointer
2792cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2793
2794<pre>
2795 @X = global i8 4
2796 @Y = global i32 123
2797
2798 @llvm.used = appending global [2 x i8*] [
2799 i8* @X,
2800 i8* bitcast (i32* @Y to i8*)
2801 ], section "llvm.metadata"
2802</pre>
2803
2804<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2805compiler, assembler, and linker are required to treat the symbol as if there is
2806a reference to the global that it cannot see. For example, if a variable has
2807internal linkage and no references other than that from the <tt>@llvm.used</tt>
2808list, it cannot be deleted. This is commonly used to represent references from
2809inline asms and other things the compiler cannot "see", and corresponds to
2810"attribute((used))" in GNU C.</p>
2811
2812<p>On some targets, the code generator must emit a directive to the assembler or
2813object file to prevent the assembler and linker from molesting the symbol.</p>
2814
2815</div>
2816
2817<!-- ======================================================================= -->
2818<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2819<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2820</div>
2821
2822<div class="doc_text">
2823
2824<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2825<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2826touching the symbol. On targets that support it, this allows an intelligent
2827linker to optimize references to the symbol without being impeded as it would be
2828by <tt>@llvm.used</tt>.</p>
2829
2830<p>This is a rare construct that should only be used in rare circumstances, and
2831should not be exposed to source languages.</p>
2832
2833</div>
2834
2835<!-- ======================================================================= -->
2836<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2837<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2838</div>
2839
2840<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2841<pre>
2842%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2843@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2844</pre>
2845<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2846</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2847
2848</div>
2849
2850<!-- ======================================================================= -->
2851<div class="doc_subsection">
2852<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2853</div>
2854
2855<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2856<pre>
2857%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2858@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2859</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2860
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2861<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2862</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2863
2864</div>
2865
2866
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2867<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2868<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2869<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2870
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2871<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2872
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2873<p>The LLVM instruction set consists of several different classifications of
2874 instructions: <a href="#terminators">terminator
2875 instructions</a>, <a href="#binaryops">binary instructions</a>,
2876 <a href="#bitwiseops">bitwise binary instructions</a>,
2877 <a href="#memoryops">memory instructions</a>, and
2878 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2879
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2880</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2881
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2882<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2883<div class="doc_subsection"> <a name="terminators">Terminator
2884Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2886<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2887
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2888<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2889 in a program ends with a "Terminator" instruction, which indicates which
2890 block should be executed after the current block is finished. These
2891 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2892 control flow, not values (the one exception being the
2893 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2894
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2895<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2896 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2897 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2898 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2899 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2900 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2901 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2902 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2904</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2906<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2907<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2908Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2909
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2910<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2913<pre>
2914 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]2915 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2916</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2920 a value) from a function back to the caller.</p>
2921
2922<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2923 value and then causes control flow, and one that just causes control flow to
2924 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2927<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2928 return value. The type of the return value must be a
2929 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2930
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2932 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2933 value or a return value with a type that does not match its type, or if it
2934 has a void return type and contains a '<tt>ret</tt>' instruction with a
2935 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2939 the calling function's context. If the caller is a
2940 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2941 instruction after the call. If the caller was an
2942 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2943 the beginning of the "normal" destination block. If the instruction returns
2944 a value, that value shall set the call or invoke instruction's return
2945 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2947<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2948<pre>
2949 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2950 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2951 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]2952</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2953
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2954</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2955<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2956<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2958<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2960<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961<pre>
2962 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]2963</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2965<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2967 different basic block in the current function. There are two forms of this
2968 instruction, corresponding to a conditional branch and an unconditional
2969 branch.</p>
2970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2971<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2973 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2974 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2975 target.</p>
2976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2977<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2978<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2979 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2980 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2981 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2984<pre>
2985Test:
2986 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2987 br i1 %cond, label %IfEqual, label %IfUnequal
2988IfEqual:
2989 <a href="#i_ret">ret</a> i32 1
2990IfUnequal:
2991 <a href="#i_ret">ret</a> i32 0
2992</pre>
2993
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2994</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2995
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2996<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2997<div class="doc_subsubsection">
2998 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2999</div>
3000
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3001<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3003<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3004<pre>
3005 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3006</pre>
3007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3008<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3009<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]3010 several different places. It is a generalization of the '<tt>br</tt>'
3011 instruction, allowing a branch to occur to one of many possible
3012 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3013
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3014<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3015<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3016 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3017 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3018 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3019
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3020<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3021<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3022 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3023 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3024 transferred to the corresponding destination; otherwise, control flow is
3025 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3026
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3027<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3028<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3029 <tt>switch</tt> instruction, this instruction may be code generated in
3030 different ways. For example, it could be generated as a series of chained
3031 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3032
3033<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3034<pre>
3035 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3036 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3037 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3038
3039 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3040 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3041
3042 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3043 switch i32 %val, label %otherwise [ i32 0, label %onzero
3044 i32 1, label %onone
3045 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3046</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3048</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3050
3051<!-- _______________________________________________________________________ -->
3052<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3053 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3054</div>
3055
3056<div class="doc_text">
3057
3058<h5>Syntax:</h5>
3059<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3060 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]3061</pre>
3062
3063<h5>Overview:</h5>
3064
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3065<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3066 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3067 "<tt>address</tt>". Address must be derived from a <a
3068 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3069
3070<h5>Arguments:</h5>
3071
3072<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3073 rest of the arguments indicate the full set of possible destinations that the
3074 address may point to. Blocks are allowed to occur multiple times in the
3075 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3076
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3077<p>This destination list is required so that dataflow analysis has an accurate
3078 understanding of the CFG.</p>
3079
3080<h5>Semantics:</h5>
3081
3082<p>Control transfers to the block specified in the address argument. All
3083 possible destination blocks must be listed in the label list, otherwise this
3084 instruction has undefined behavior. This implies that jumps to labels
3085 defined in other functions have undefined behavior as well.</p>
3086
3087<h5>Implementation:</h5>
3088
3089<p>This is typically implemented with a jump through a register.</p>
3090
3091<h5>Example:</h5>
3092<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3093 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3094</pre>
3095
3096</div>
3097
3098
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3099<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3100<div class="doc_subsubsection">
3101 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3102</div>
3103
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3104<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3105
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3106<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3108 &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]3109 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3110</pre>
3111
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3112<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3113<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3114 function, with the possibility of control flow transfer to either the
3115 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3116 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3117 control flow will return to the "normal" label. If the callee (or any
3118 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3119 instruction, control is interrupted and continued at the dynamically nearest
3120 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3121
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3122<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3123<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3125<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3127 convention</a> the call should use. If none is specified, the call
3128 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3129
3130 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3132 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3133
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3134 <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]3135 function value being invoked. In most cases, this is a direct function
3136 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3137 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3138
3139 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3141
3142 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3143 signature argument types and parameter attributes. All arguments must be
3144 of <a href="#t_firstclass">first class</a> type. If the function
3145 signature indicates the function accepts a variable number of arguments,
3146 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3147
3148 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3150
3151 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3153
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3154 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3155 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3156 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3157</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3158
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3159<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3160<p>This instruction is designed to operate as a standard
3161 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3162 primary difference is that it establishes an association with a label, which
3163 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3164
3165<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3167 exception. Additionally, this is important for implementation of
3168 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3169
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170<p>For the purposes of the SSA form, the definition of the value returned by the
3171 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3172 block to the "normal" label. If the callee unwinds then no return value is
3173 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3174
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3175<p>Note that the code generator does not yet completely support unwind, and
3176that the invoke/unwind semantics are likely to change in future versions.</p>
3177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3178<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3179<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3180 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3181 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3182 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3183 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3184</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3185
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3186</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3187
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3188<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3189
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3190<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3191Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3192
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3193<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3194
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3195<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3196<pre>
3197 unwind
3198</pre>
3199
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3200<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3201<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202 at the first callee in the dynamic call stack which used
3203 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3204 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3205
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3206<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3207<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3208 immediately halt. The dynamic call stack is then searched for the
3209 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3210 Once found, execution continues at the "exceptional" destination block
3211 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3212 instruction in the dynamic call chain, undefined behavior results.</p>
3213
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3214<p>Note that the code generator does not yet completely support unwind, and
3215that the invoke/unwind semantics are likely to change in future versions.</p>
3216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3217</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3218
3219<!-- _______________________________________________________________________ -->
3220
3221<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3222Instruction</a> </div>
3223
3224<div class="doc_text">
3225
3226<h5>Syntax:</h5>
3227<pre>
3228 unreachable
3229</pre>
3230
3231<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3232<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3233 instruction is used to inform the optimizer that a particular portion of the
3234 code is not reachable. This can be used to indicate that the code after a
3235 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3236
3237<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3238<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3239
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3240</div>
3241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3242<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3243<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3245<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3246
3247<p>Binary operators are used to do most of the computation in a program. They
3248 require two operands of the same type, execute an operation on them, and
3249 produce a single value. The operands might represent multiple data, as is
3250 the case with the <a href="#t_vector">vector</a> data type. The result value
3251 has the same type as its operands.</p>
3252
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3253<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3255</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3257<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3258<div class="doc_subsubsection">
3259 <a name="i_add">'<tt>add</tt>' Instruction</a>
3260</div>
3261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3262<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3264<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3265<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3266 &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]3267 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3268 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3269 &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]3270</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3271
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3272<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3273<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3275<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276<p>The two arguments to the '<tt>add</tt>' instruction must
3277 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3278 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3279
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3280<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3283<p>If the sum has unsigned overflow, the result returned is the mathematical
3284 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]3285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286<p>Because LLVM integers use a two's complement representation, this instruction
3287 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3288
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3289<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3290 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3291 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3292 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3293 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3296<pre>
3297 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3300</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3301
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3302<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3304 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3305</div>
3306
3307<div class="doc_text">
3308
3309<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3310<pre>
3311 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3312</pre>
3313
3314<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3315<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3316
3317<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3320 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3321
3322<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3323<p>The value produced is the floating point sum of the two operands.</p>
3324
3325<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3328</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3329
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3330</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3332<!-- _______________________________________________________________________ -->
3333<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3334 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3335</div>
3336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3337<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3338
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3339<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3340<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3341 &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]3342 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3343 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3344 &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]3345</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3346
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3347<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3348<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3350
3351<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352 '<tt>neg</tt>' instruction present in most other intermediate
3353 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3354
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3355<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3356<p>The two arguments to the '<tt>sub</tt>' instruction must
3357 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3358 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3359
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3360<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3361<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3362
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3363<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3365 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367<p>Because LLVM integers use a two's complement representation, this instruction
3368 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3369
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3370<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3371 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3372 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3373 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3374 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3377<pre>
3378 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3379 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3380</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3381
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3382</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3385<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3386 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3387</div>
3388
3389<div class="doc_text">
3390
3391<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3392<pre>
3393 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3394</pre>
3395
3396<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3397<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3399
3400<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3401 '<tt>fneg</tt>' instruction present in most other intermediate
3402 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3403
3404<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3405<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3406 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3407 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3408
3409<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3410<p>The value produced is the floating point difference of the two operands.</p>
3411
3412<h5>Example:</h5>
3413<pre>
3414 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3415 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3416</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3418</div>
3419
3420<!-- _______________________________________________________________________ -->
3421<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3422 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3423</div>
3424
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3425<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3427<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3429 &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]3430 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3431 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3432 &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]3433</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3435<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3438<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439<p>The two arguments to the '<tt>mul</tt>' instruction must
3440 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3441 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3443<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3444<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3445
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446<p>If the result of the multiplication has unsigned overflow, the result
3447 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3448 width of the result.</p>
3449
3450<p>Because LLVM integers use a two's complement representation, and the result
3451 is the same width as the operands, this instruction returns the correct
3452 result for both signed and unsigned integers. If a full product
3453 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3454 be sign-extended or zero-extended as appropriate to the width of the full
3455 product.</p>
3456
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3457<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3458 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3459 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3460 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3461 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3462
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3463<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3466</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3468</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3471<div class="doc_subsubsection">
3472 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3473</div>
3474
3475<div class="doc_text">
3476
3477<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478<pre>
3479 &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]3480</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3481
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3484
3485<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3486<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3488 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3489
3490<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3491<p>The value produced is the floating point product of the two operands.</p>
3492
3493<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494<pre>
3495 &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]3496</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3498</div>
3499
3500<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3501<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3502</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3504<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3506<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3507<pre>
3508 &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]3509</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3510
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3511<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3513
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3514<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3515<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3516 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3517 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3518
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3519<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3520<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3522<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3524
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3525<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3527<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528<pre>
3529 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3530</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3532</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3534<!-- _______________________________________________________________________ -->
3535<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3536</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3538<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3540<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3541<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3542 &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]3543 &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]3544</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3545
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3546<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3549<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3550<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3552 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3554<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555<p>The value produced is the signed integer quotient of the two operands rounded
3556 towards zero.</p>
3557
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3558<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3560
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3561<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562 undefined behavior; this is a rare case, but can occur, for example, by doing
3563 a 32-bit division of -2147483648 by -1.</p>
3564
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3565<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3566 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3567 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3568
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3569<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<pre>
3571 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3572</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3574</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3576<!-- _______________________________________________________________________ -->
3577<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3579
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3580<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3583<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3584 &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]3585</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3586
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3587<h5>Overview:</h5>
3588<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3590<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3591<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3593 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3594
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3595<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3596<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
3600 &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]3601</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3603</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3604
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3605<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3606<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3607</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3608
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3609<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612<pre>
3613 &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]3614</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3616<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3618 division of its two arguments.</p>
3619
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3620<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3621<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3623 values. Both arguments must have identical types.</p>
3624
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3625<h5>Semantics:</h5>
3626<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627 This instruction always performs an unsigned division to get the
3628 remainder.</p>
3629
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3630<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3632
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3633<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3634
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3635<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636<pre>
3637 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3638</pre>
3639
3640</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3642<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3643<div class="doc_subsubsection">
3644 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3645</div>
3646
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3647<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3648
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3649<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3650<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3651 &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]3652</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3653
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3654<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3655<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3656 division of its two operands. This instruction can also take
3657 <a href="#t_vector">vector</a> versions of the values in which case the
3658 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3659
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3660<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3661<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3663 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3665<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3666<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3668 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3669 a value. For more information about the difference,
3670 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3671 Math Forum</a>. For a table of how this is implemented in various languages,
3672 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3673 Wikipedia: modulo operation</a>.</p>
3674
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3675<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3676 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3677
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3678<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679 Overflow also leads to undefined behavior; this is a rare case, but can
3680 occur, for example, by taking the remainder of a 32-bit division of
3681 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3682 lets srem be implemented using instructions that return both the result of
3683 the division and the remainder.)</p>
3684
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3685<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<pre>
3687 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3688</pre>
3689
3690</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3692<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3693<div class="doc_subsubsection">
3694 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3695
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3696<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3697
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3698<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699<pre>
3700 &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]3701</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3703<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3705 its two operands.</p>
3706
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3707<h5>Arguments:</h5>
3708<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3710 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3711
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3712<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3713<p>This instruction returns the <i>remainder</i> of a division. The remainder
3714 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3715
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3716<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3717<pre>
3718 &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]3719</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3721</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3722
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3723<!-- ======================================================================= -->
3724<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3725Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3727<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728
3729<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3730 program. They are generally very efficient instructions and can commonly be
3731 strength reduced from other instructions. They require two operands of the
3732 same type, execute an operation on them, and produce a single value. The
3733 resulting value is the same type as its operands.</p>
3734
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3735</div>
3736
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3739Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3741<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3743<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744<pre>
3745 &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]3746</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3747
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3748<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3750 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3751
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3752<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3753<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3754 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3755 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3756
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3757<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3759 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3760 is (statically or dynamically) negative or equal to or larger than the number
3761 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3762 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3763 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3764
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765<h5>Example:</h5>
3766<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3767 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3768 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3769 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3770 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3771 &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]3772</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3774</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3775
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3776<!-- _______________________________________________________________________ -->
3777<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3778Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3779
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3780<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3781
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3782<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3783<pre>
3784 &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]3785</pre>
3786
3787<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3788<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3789 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3790
3791<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3792<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3794 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3795
3796<h5>Semantics:</h5>
3797<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3798 significant bits of the result will be filled with zero bits after the shift.
3799 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3800 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3801 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3802 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3803
3804<h5>Example:</h5>
3805<pre>
3806 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3807 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3808 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3809 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3810 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3811 &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]3812</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3813
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3814</div>
3815
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3816<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3817<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3818Instruction</a> </div>
3819<div class="doc_text">
3820
3821<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3822<pre>
3823 &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]3824</pre>
3825
3826<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3828 operand shifted to the right a specified number of bits with sign
3829 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3830
3831<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3832<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3833 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3834 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3835
3836<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3837<p>This instruction always performs an arithmetic shift right operation, The
3838 most significant bits of the result will be filled with the sign bit
3839 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3840 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3841 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3842 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3843
3844<h5>Example:</h5>
3845<pre>
3846 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3847 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3848 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3849 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3850 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3851 &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]3852</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3854</div>
3855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3856<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3857<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3858Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3860<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3862<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3863<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3864 &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]3865</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3866
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3867<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3869 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3871<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3872<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3873 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3874 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3876<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3877<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3879<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3880 <tbody>
3881 <tr>
3882 <td>In0</td>
3883 <td>In1</td>
3884 <td>Out</td>
3885 </tr>
3886 <tr>
3887 <td>0</td>
3888 <td>0</td>
3889 <td>0</td>
3890 </tr>
3891 <tr>
3892 <td>0</td>
3893 <td>1</td>
3894 <td>0</td>
3895 </tr>
3896 <tr>
3897 <td>1</td>
3898 <td>0</td>
3899 <td>0</td>
3900 </tr>
3901 <tr>
3902 <td>1</td>
3903 <td>1</td>
3904 <td>1</td>
3905 </tr>
3906 </tbody>
3907</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3910<pre>
3911 &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]3912 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3913 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3914</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3915</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3916<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3917<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919<div class="doc_text">
3920
3921<h5>Syntax:</h5>
3922<pre>
3923 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3924</pre>
3925
3926<h5>Overview:</h5>
3927<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3928 two operands.</p>
3929
3930<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3931<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3932 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3933 values. Both arguments must have identical types.</p>
3934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3936<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3938<table border="1" cellspacing="0" cellpadding="4">
3939 <tbody>
3940 <tr>
3941 <td>In0</td>
3942 <td>In1</td>
3943 <td>Out</td>
3944 </tr>
3945 <tr>
3946 <td>0</td>
3947 <td>0</td>
3948 <td>0</td>
3949 </tr>
3950 <tr>
3951 <td>0</td>
3952 <td>1</td>
3953 <td>1</td>
3954 </tr>
3955 <tr>
3956 <td>1</td>
3957 <td>0</td>
3958 <td>1</td>
3959 </tr>
3960 <tr>
3961 <td>1</td>
3962 <td>1</td>
3963 <td>1</td>
3964 </tr>
3965 </tbody>
3966</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3968<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969<pre>
3970 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3971 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3972 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3975</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3977<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3978<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3979Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3980
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3981<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3983<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3984<pre>
3985 &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]3986</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3988<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3990 its two operands. The <tt>xor</tt> is used to implement the "one's
3991 complement" operation, which is the "~" operator in C.</p>
3992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3993<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3994<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3996 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3997
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3998<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3999<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4001<table border="1" cellspacing="0" cellpadding="4">
4002 <tbody>
4003 <tr>
4004 <td>In0</td>
4005 <td>In1</td>
4006 <td>Out</td>
4007 </tr>
4008 <tr>
4009 <td>0</td>
4010 <td>0</td>
4011 <td>0</td>
4012 </tr>
4013 <tr>
4014 <td>0</td>
4015 <td>1</td>
4016 <td>1</td>
4017 </tr>
4018 <tr>
4019 <td>1</td>
4020 <td>0</td>
4021 <td>1</td>
4022 </tr>
4023 <tr>
4024 <td>1</td>
4025 <td>1</td>
4026 <td>0</td>
4027 </tr>
4028 </tbody>
4029</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4031<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032<pre>
4033 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4034 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4035 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4036 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4037</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4039</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4040
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4041<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4042<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4043 <a name="vectorops">Vector Operations</a>
4044</div>
4045
4046<div class="doc_text">
4047
4048<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049 target-independent manner. These instructions cover the element-access and
4050 vector-specific operations needed to process vectors effectively. While LLVM
4051 does directly support these vector operations, many sophisticated algorithms
4052 will want to use target-specific intrinsics to take full advantage of a
4053 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4054
4055</div>
4056
4057<!-- _______________________________________________________________________ -->
4058<div class="doc_subsubsection">
4059 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4060</div>
4061
4062<div class="doc_text">
4063
4064<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4065<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4066 &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]4067</pre>
4068
4069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4071 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4072
4073
4074<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4076 of <a href="#t_vector">vector</a> type. The second operand is an index
4077 indicating the position from which to extract the element. The index may be
4078 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4079
4080<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081<p>The result is a scalar of the same type as the element type of
4082 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4083 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4084 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4085
4086<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4087<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4088 &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]4089</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4090
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4092
4093<!-- _______________________________________________________________________ -->
4094<div class="doc_subsubsection">
4095 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4096</div>
4097
4098<div class="doc_text">
4099
4100<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4101<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4102 &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]4103</pre>
4104
4105<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4107 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4108
4109<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4110<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4111 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4112 whose type must equal the element type of the first operand. The third
4113 operand is an index indicating the position at which to insert the value.
4114 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4115
4116<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4117<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4118 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4119 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4120 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4121
4122<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4123<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4124 &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]4125</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4127</div>
4128
4129<!-- _______________________________________________________________________ -->
4130<div class="doc_subsubsection">
4131 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4132</div>
4133
4134<div class="doc_text">
4135
4136<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4137<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4138 &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]4139</pre>
4140
4141<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4143 from two input vectors, returning a vector with the same element type as the
4144 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4145
4146<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4147<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4148 with types that match each other. The third argument is a shuffle mask whose
4149 element type is always 'i32'. The result of the instruction is a vector
4150 whose length is the same as the shuffle mask and whose element type is the
4151 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4152
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4153<p>The shuffle mask operand is required to be a constant vector with either
4154 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4155
4156<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4157<p>The elements of the two input vectors are numbered from left to right across
4158 both of the vectors. The shuffle mask operand specifies, for each element of
4159 the result vector, which element of the two input vectors the result element
4160 gets. The element selector may be undef (meaning "don't care") and the
4161 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4162
4163<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4164<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4165 &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]4166 &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]4167 &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]4168 &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]4169 &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]4170 &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]4171 &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]4172 &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]4173</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4174
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4176
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4177<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4178<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4179 <a name="aggregateops">Aggregate Operations</a>
4180</div>
4181
4182<div class="doc_text">
4183
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4184<p>LLVM supports several instructions for working with
4185 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4186
4187</div>
4188
4189<!-- _______________________________________________________________________ -->
4190<div class="doc_subsubsection">
4191 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4192</div>
4193
4194<div class="doc_text">
4195
4196<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197<pre>
4198 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4199</pre>
4200
4201<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4202<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4203 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4204
4205<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4207 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4208 <a href="#t_array">array</a> type. The operands are constant indices to
4209 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4211
4212<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4213<p>The result is the value at the position in the aggregate specified by the
4214 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4215
4216<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4217<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4218 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4219</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4220
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4221</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4222
4223<!-- _______________________________________________________________________ -->
4224<div class="doc_subsubsection">
4225 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4226</div>
4227
4228<div class="doc_text">
4229
4230<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4231<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4232 &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]4233</pre>
4234
4235<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4236<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4237 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4238
4239<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4241 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4242 <a href="#t_array">array</a> type. The second operand is a first-class
4243 value to insert. The following operands are constant indices indicating
4244 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]4245 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4246 value to insert must have the same type as the value identified by the
4247 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4248
4249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4251 that of <tt>val</tt> except that the value at the position specified by the
4252 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4253
4254<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4255<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4256 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4257 %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]4258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4260</div>
4261
4262
4263<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4264<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4265 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4266</div>
4267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4268<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270<p>A key design point of an SSA-based representation is how it represents
4271 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4272 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4278<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4279 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4280</div>
4281
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4282<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4283
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4284<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4285<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4286 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4287</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4289<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4290<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291 currently executing function, to be automatically released when this function
4292 returns to its caller. The object is always allocated in the generic address
4293 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4295<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296<p>The '<tt>alloca</tt>' instruction
4297 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4298 runtime stack, returning a pointer of the appropriate type to the program.
4299 If "NumElements" is specified, it is the number of elements allocated,
4300 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4301 specified, the value result of the allocation is guaranteed to be aligned to
4302 at least that boundary. If not specified, or if zero, the target can choose
4303 to align the allocation on any convenient boundary compatible with the
4304 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4306<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4307
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4308<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4309<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4311 memory is automatically released when the function returns. The
4312 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4313 variables that must have an address available. When the function returns
4314 (either with the <tt><a href="#i_ret">ret</a></tt>
4315 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4316 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4318<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4319<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4320 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4321 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4322 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4323 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4324</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4326</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4327
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4328<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4329<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4330Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4332<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4334<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4336 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4337 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4338 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339</pre>
4340
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4342<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4344<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4346 from which to load. The pointer must point to
4347 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4348 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4349 number or order of execution of this <tt>load</tt> with other <a
4350 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4352<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353 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]4354 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355 alignment for the target. It is the responsibility of the code emitter to
4356 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4357 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358 produce less efficient code. An alignment of 1 is always safe.</p>
4359
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4360<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4361 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4362 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4363 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4364 and code generator that this load is not expected to be reused in the cache.
4365 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4366 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4367
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4368<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369<p>The location of memory pointed to is loaded. If the value being loaded is of
4370 scalar type then the number of bytes read does not exceed the minimum number
4371 of bytes needed to hold all bits of the type. For example, loading an
4372 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4373 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4374 is undefined if the value was not originally written using a store of the
4375 same type.</p>
4376
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4377<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4378<pre>
4379 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4380 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4381 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4384</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4385
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4386<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4387<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4388Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4389
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4392<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4394 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4395 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]4396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4398<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4399<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4401<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4403 and an address at which to store it. The type of the
4404 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4405 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4406 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4407 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4408 order of execution of this <tt>store</tt> with other <a
4409 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410
4411<p>The optional constant "align" argument specifies the alignment of the
4412 operation (that is, the alignment of the memory address). A value of 0 or an
4413 omitted "align" argument means that the operation has the preferential
4414 alignment for the target. It is the responsibility of the code emitter to
4415 ensure that the alignment information is correct. Overestimating the
4416 alignment results in an undefined behavior. Underestimating the alignment may
4417 produce less efficient code. An alignment of 1 is always safe.</p>
4418
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4419<p>The optional !nontemporal metadata must reference a single metatadata
4420 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4421 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4422 instruction tells the optimizer and code generator that this load is
4423 not expected to be reused in the cache. The code generator may
4424 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4425 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4426
4427
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4428<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4430 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4431 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4432 does not exceed the minimum number of bytes needed to hold all bits of the
4433 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4434 writing a value of a type like <tt>i20</tt> with a size that is not an
4435 integral number of bytes, it is unspecified what happens to the extra bits
4436 that do not belong to the type, but they will typically be overwritten.</p>
4437
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4438<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439<pre>
4440 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4441 store i32 3, i32* %ptr <i>; yields {void}</i>
4442 %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]4443</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4444
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4445</div>
4446
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4447<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4448<div class="doc_subsubsection">
4449 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4450</div>
4451
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4452<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4454<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4455<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4456 &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]4457 &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]4458</pre>
4459
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4461<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4462 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4463 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4464
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4465<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4466<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4467 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4468 elements of the aggregate object are indexed. The interpretation of each
4469 index is dependent on the type being indexed into. The first index always
4470 indexes the pointer value given as the first argument, the second index
4471 indexes a value of the type pointed to (not necessarily the value directly
4472 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4473 indexed into must be a pointer value, subsequent types can be arrays,
4474 vectors, structs and unions. Note that subsequent types being indexed into
4475 can never be pointers, since that would require loading the pointer before
4476 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4477
4478<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]4479 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4480 integer <b>constants</b> are allowed. When indexing into an array, pointer
4481 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]4482 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4483
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4484<p>For example, let's consider a C code fragment and how it gets compiled to
4485 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4486
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4487<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4488<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4489struct RT {
4490 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4491 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4492 char C;
4493};
4494struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4495 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4496 double Y;
4497 struct RT Z;
4498};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4499
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4500int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4501 return &amp;s[1].Z.B[5][13];
4502}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4503</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4504</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4505
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4506<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4507
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4508<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4509<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4510%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4511%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4512
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4513define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4514entry:
4515 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4516 ret i32* %reg
4517}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4518</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4519</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4520
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4521<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4522<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]4523 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4524 }</tt>' type, a structure. The second index indexes into the third element
4525 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4526 i8 }</tt>' type, another structure. The third index indexes into the second
4527 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4528 array. The two dimensions of the array are subscripted into, yielding an
4529 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4530 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4531
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4532<p>Note that it is perfectly legal to index partially through a structure,
4533 returning a pointer to an inner element. Because of this, the LLVM code for
4534 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4535
4536<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4537 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4538 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4539 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4540 %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]4541 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4542 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4543 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4544 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4545</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4546
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4547<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4548 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4549 base pointer is not an <i>in bounds</i> address of an allocated object,
4550 or if any of the addresses that would be formed by successive addition of
4551 the offsets implied by the indices to the base address with infinitely
4552 precise arithmetic are not an <i>in bounds</i> address of that allocated
4553 object. The <i>in bounds</i> addresses for an allocated object are all
4554 the addresses that point into the object, plus the address one byte past
4555 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4556
4557<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4558 the base address with silently-wrapping two's complement arithmetic, and
4559 the result value of the <tt>getelementptr</tt> may be outside the object
4560 pointed to by the base pointer. The result value may not necessarily be
4561 used to access memory though, even if it happens to point into allocated
4562 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4563 section for more information.</p>
4564
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4565<p>The getelementptr instruction is often confusing. For some more insight into
4566 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4567
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4568<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4569<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4570 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4571 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4572 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4573 %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]4574 <i>; yields i8*:eptr</i>
4575 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4576 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4577 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4578</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4580</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4582<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4583<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4584</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4586<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4587
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4588<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4589 which all take a single operand and a type. They perform various bit
4590 conversions on the operand.</p>
4591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4592</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4593
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4594<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4595<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4596 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4597</div>
4598<div class="doc_text">
4599
4600<h5>Syntax:</h5>
4601<pre>
4602 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4603</pre>
4604
4605<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4607 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4608
4609<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4610<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4611 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4612 size and type of the result, which must be
4613 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4614 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4615 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616
4617<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4618<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4619 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4620 source size must be larger than the destination size, <tt>trunc</tt> cannot
4621 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4622
4623<h5>Example:</h5>
4624<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4625 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4626 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4627 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4629
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4630</div>
4631
4632<!-- _______________________________________________________________________ -->
4633<div class="doc_subsubsection">
4634 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4635</div>
4636<div class="doc_text">
4637
4638<h5>Syntax:</h5>
4639<pre>
4640 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4641</pre>
4642
4643<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4644<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4646
4647
4648<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4649<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]4650 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4651 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]4652 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4653 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4654
4655<h5>Semantics:</h5>
4656<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]4657 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4658
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4659<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]4660
4661<h5>Example:</h5>
4662<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4663 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4664 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4665</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4667</div>
4668
4669<!-- _______________________________________________________________________ -->
4670<div class="doc_subsubsection">
4671 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4672</div>
4673<div class="doc_text">
4674
4675<h5>Syntax:</h5>
4676<pre>
4677 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4678</pre>
4679
4680<h5>Overview:</h5>
4681<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4682
4683<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4684<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]4685 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4686 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]4687 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4689
4690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4692 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4693 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4694
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4695<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]4696
4697<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4698<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4699 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4700 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4701</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4702
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4703</div>
4704
4705<!-- _______________________________________________________________________ -->
4706<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4707 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4708</div>
4709
4710<div class="doc_text">
4711
4712<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4713<pre>
4714 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4715</pre>
4716
4717<h5>Overview:</h5>
4718<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4720
4721<h5>Arguments:</h5>
4722<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4724 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]4725 <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]4726 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4727
4728<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4730 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731 <a href="#t_floating">floating point</a> type. If the value cannot fit
4732 within the destination type, <tt>ty2</tt>, then the results are
4733 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4734
4735<h5>Example:</h5>
4736<pre>
4737 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4738 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4739</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4741</div>
4742
4743<!-- _______________________________________________________________________ -->
4744<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4745 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4746</div>
4747<div class="doc_text">
4748
4749<h5>Syntax:</h5>
4750<pre>
4751 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4752</pre>
4753
4754<h5>Overview:</h5>
4755<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]4756 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4757
4758<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4759<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4761 a <a href="#t_floating">floating point</a> type to cast it to. The source
4762 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763
4764<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4765<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4766 <a href="#t_floating">floating point</a> type to a larger
4767 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4768 used to make a <i>no-op cast</i> because it always changes bits. Use
4769 <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]4770
4771<h5>Example:</h5>
4772<pre>
4773 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4774 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4775</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4777</div>
4778
4779<!-- _______________________________________________________________________ -->
4780<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4781 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4782</div>
4783<div class="doc_text">
4784
4785<h5>Syntax:</h5>
4786<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4787 &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]4788</pre>
4789
4790<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4791<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4792 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4793
4794<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4795<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4796 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4797 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4798 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4799 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800
4801<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4802<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4803 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4804 towards zero) unsigned integer value. If the value cannot fit
4805 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4806
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807<h5>Example:</h5>
4808<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4809 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4810 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4811 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4812</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4814</div>
4815
4816<!-- _______________________________________________________________________ -->
4817<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4818 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4819</div>
4820<div class="doc_text">
4821
4822<h5>Syntax:</h5>
4823<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4824 &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]4825</pre>
4826
4827<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4828<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4829 <a href="#t_floating">floating point</a> <tt>value</tt> to
4830 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4831
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4832<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4833<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4834 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4835 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4836 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4837 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4838
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4839<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4840<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4841 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4842 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4843 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4844
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4845<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4846<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4847 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4848 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4849 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4850</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4851
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4852</div>
4853
4854<!-- _______________________________________________________________________ -->
4855<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4856 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4857</div>
4858<div class="doc_text">
4859
4860<h5>Syntax:</h5>
4861<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4862 &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]4863</pre>
4864
4865<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4866<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4867 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4868
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4869<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4870<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]4871 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4872 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4873 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4874 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4875
4876<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4877<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4878 integer quantity and converts it to the corresponding floating point
4879 value. If the value cannot fit in the floating point value, the results are
4880 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4881
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4882<h5>Example:</h5>
4883<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4884 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4885 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4886</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4888</div>
4889
4890<!-- _______________________________________________________________________ -->
4891<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4892 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4893</div>
4894<div class="doc_text">
4895
4896<h5>Syntax:</h5>
4897<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4898 &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]4899</pre>
4900
4901<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4902<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4903 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4904
4905<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4906<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]4907 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4908 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4909 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4910 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4911
4912<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4913<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4914 quantity and converts it to the corresponding floating point value. If the
4915 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4916
4917<h5>Example:</h5>
4918<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4919 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4920 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4922
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4923</div>
4924
4925<!-- _______________________________________________________________________ -->
4926<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4927 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4928</div>
4929<div class="doc_text">
4930
4931<h5>Syntax:</h5>
4932<pre>
4933 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4934</pre>
4935
4936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4938 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4939
4940<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4941<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4942 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4943 <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]4944
4945<h5>Semantics:</h5>
4946<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4947 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4948 truncating or zero extending that value to the size of the integer type. If
4949 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4950 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4951 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4952 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4953
4954<h5>Example:</h5>
4955<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4956 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4957 %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]4958</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4959
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4960</div>
4961
4962<!-- _______________________________________________________________________ -->
4963<div class="doc_subsubsection">
4964 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4965</div>
4966<div class="doc_text">
4967
4968<h5>Syntax:</h5>
4969<pre>
4970 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4971</pre>
4972
4973<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4975 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4976
4977<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4978<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979 value to cast, and a type to cast it to, which must be a
4980 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4981
4982<h5>Semantics:</h5>
4983<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4985 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4986 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4987 than the size of a pointer then a zero extension is done. If they are the
4988 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4989
4990<h5>Example:</h5>
4991<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4992 %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]4993 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4994 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4997</div>
4998
4999<!-- _______________________________________________________________________ -->
5000<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5001 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5002</div>
5003<div class="doc_text">
5004
5005<h5>Syntax:</h5>
5006<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5007 &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]5008</pre>
5009
5010<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5011<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5013
5014<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5015<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5016 non-aggregate first class value, and a type to cast it to, which must also be
5017 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5018 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5019 identical. If the source type is a pointer, the destination type must also be
5020 a pointer. This instruction supports bitwise conversion of vectors to
5021 integers and to vectors of other types (as long as they have the same
5022 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5023
5024<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5025<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5026 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5027 this conversion. The conversion is done as if the <tt>value</tt> had been
5028 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5029 be converted to other pointer types with this instruction. To convert
5030 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5031 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5032
5033<h5>Example:</h5>
5034<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5035 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5036 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5037 %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]5038</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5039
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5040</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5041
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5042<!-- ======================================================================= -->
5043<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5045<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5046
5047<p>The instructions in this category are the "miscellaneous" instructions, which
5048 defy better classification.</p>
5049
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5050</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5051
5052<!-- _______________________________________________________________________ -->
5053<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5054</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5055
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5056<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5057
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059<pre>
5060 &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]5061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5062
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5064<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5065 boolean values based on comparison of its two integer, integer vector, or
5066 pointer operands.</p>
5067
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5068<h5>Arguments:</h5>
5069<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070 the condition code indicating the kind of comparison to perform. It is not a
5071 value, just a keyword. The possible condition code are:</p>
5072
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073<ol>
5074 <li><tt>eq</tt>: equal</li>
5075 <li><tt>ne</tt>: not equal </li>
5076 <li><tt>ugt</tt>: unsigned greater than</li>
5077 <li><tt>uge</tt>: unsigned greater or equal</li>
5078 <li><tt>ult</tt>: unsigned less than</li>
5079 <li><tt>ule</tt>: unsigned less or equal</li>
5080 <li><tt>sgt</tt>: signed greater than</li>
5081 <li><tt>sge</tt>: signed greater or equal</li>
5082 <li><tt>slt</tt>: signed less than</li>
5083 <li><tt>sle</tt>: signed less or equal</li>
5084</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5085
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5086<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5087 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5088 typed. They must also be identical types.</p>
5089
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5090<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5091<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5092 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5093 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]5094 result, as follows:</p>
5095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5097 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5098 <tt>false</tt> otherwise. No sign interpretation is necessary or
5099 performed.</li>
5100
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5101 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102 <tt>false</tt> otherwise. No sign interpretation is necessary or
5103 performed.</li>
5104
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5105 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5107
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5108 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5110 to <tt>op2</tt>.</li>
5111
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5112 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5114
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5115 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5117
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5118 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5119 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5120
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5121 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5123 to <tt>op2</tt>.</li>
5124
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5125 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5126 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5127
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5128 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5129 <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]5130</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5131
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5132<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5133 values are compared as if they were integers.</p>
5134
5135<p>If the operands are integer vectors, then they are compared element by
5136 element. The result is an <tt>i1</tt> vector with the same number of elements
5137 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5138
5139<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5140<pre>
5141 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5142 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5143 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5144 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5145 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5146 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5147</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5148
5149<p>Note that the code generator does not yet support vector types with
5150 the <tt>icmp</tt> instruction.</p>
5151
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5152</div>
5153
5154<!-- _______________________________________________________________________ -->
5155<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5156</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5157
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5158<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5159
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5160<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5161<pre>
5162 &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]5163</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5164
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5165<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5166<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5167 values based on comparison of its operands.</p>
5168
5169<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]5170(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5171
5172<p>If the operands are floating point vectors, then the result type is a vector
5173 of boolean with the same number of elements as the operands being
5174 compared.</p>
5175
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5176<h5>Arguments:</h5>
5177<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5178 the condition code indicating the kind of comparison to perform. It is not a
5179 value, just a keyword. The possible condition code are:</p>
5180
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5181<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5182 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5183 <li><tt>oeq</tt>: ordered and equal</li>
5184 <li><tt>ogt</tt>: ordered and greater than </li>
5185 <li><tt>oge</tt>: ordered and greater than or equal</li>
5186 <li><tt>olt</tt>: ordered and less than </li>
5187 <li><tt>ole</tt>: ordered and less than or equal</li>
5188 <li><tt>one</tt>: ordered and not equal</li>
5189 <li><tt>ord</tt>: ordered (no nans)</li>
5190 <li><tt>ueq</tt>: unordered or equal</li>
5191 <li><tt>ugt</tt>: unordered or greater than </li>
5192 <li><tt>uge</tt>: unordered or greater than or equal</li>
5193 <li><tt>ult</tt>: unordered or less than </li>
5194 <li><tt>ule</tt>: unordered or less than or equal</li>
5195 <li><tt>une</tt>: unordered or not equal</li>
5196 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5197 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5198</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5199
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5200<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5201 <i>unordered</i> means that either operand may be a QNAN.</p>
5202
5203<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5204 a <a href="#t_floating">floating point</a> type or
5205 a <a href="#t_vector">vector</a> of floating point type. They must have
5206 identical types.</p>
5207
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5208<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5209<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5210 according to the condition code given as <tt>cond</tt>. If the operands are
5211 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5212 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5213 follows:</p>
5214
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5215<ol>
5216 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5218 <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]5219 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5220
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5221 <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]5222 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5223
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5224 <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]5225 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5226
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5227 <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]5228 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5229
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5230 <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]5231 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5232
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5233 <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]5234 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5235
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5236 <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]5237
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5238 <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]5239 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5240
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5241 <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]5242 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5243
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5244 <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]5245 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5246
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5247 <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]5248 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5249
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5250 <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]5251 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5252
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5253 <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]5254 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5255
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5256 <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]5257
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5258 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5259</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5260
5261<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5262<pre>
5263 &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]5264 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5265 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5266 &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]5267</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5268
5269<p>Note that the code generator does not yet support vector types with
5270 the <tt>fcmp</tt> instruction.</p>
5271
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5272</div>
5273
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5274<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5275<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5276 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5277</div>
5278
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5279<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5280
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5281<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5282<pre>
5283 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5284</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5285
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5286<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5287<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5288 SSA graph representing the function.</p>
5289
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5290<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5291<p>The type of the incoming values is specified with the first type field. After
5292 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5293 one pair for each predecessor basic block of the current block. Only values
5294 of <a href="#t_firstclass">first class</a> type may be used as the value
5295 arguments to the PHI node. Only labels may be used as the label
5296 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5297
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5298<p>There must be no non-phi instructions between the start of a basic block and
5299 the PHI instructions: i.e. PHI instructions must be first in a basic
5300 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5301
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5302<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5303 occur on the edge from the corresponding predecessor block to the current
5304 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5305 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5306
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5307<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5308<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5309 specified by the pair corresponding to the predecessor basic block that
5310 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5311
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5312<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5313<pre>
5314Loop: ; Infinite loop that counts from 0 on up...
5315 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5316 %nextindvar = add i32 %indvar, 1
5317 br label %Loop
5318</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5319
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5320</div>
5321
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5322<!-- _______________________________________________________________________ -->
5323<div class="doc_subsubsection">
5324 <a name="i_select">'<tt>select</tt>' Instruction</a>
5325</div>
5326
5327<div class="doc_text">
5328
5329<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5330<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5331 &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>
5332
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5333 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5334</pre>
5335
5336<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5337<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5338 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5339
5340
5341<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5342<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5343 values indicating the condition, and two values of the
5344 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5345 vectors and the condition is a scalar, then entire vectors are selected, not
5346 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5347
5348<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5349<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5350 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5352<p>If the condition is a vector of i1, then the value arguments must be vectors
5353 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5354
5355<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5356<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5357 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5358</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5359
5360<p>Note that the code generator does not yet support conditions
5361 with vector type.</p>
5362
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5363</div>
5364
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5365<!-- _______________________________________________________________________ -->
5366<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5367 <a name="i_call">'<tt>call</tt>' Instruction</a>
5368</div>
5369
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5370<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5371
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5372<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5373<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5374 &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]5375</pre>
5376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5377<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5378<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5380<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5381<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5382
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5383<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5384 <li>The optional "tail" marker indicates that the callee function does not
5385 access any allocas or varargs in the caller. Note that calls may be
5386 marked "tail" even if they do not occur before
5387 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5388 present, the function call is eligible for tail call optimization,
5389 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5390 optimized into a jump</a>. The code generator may optimize calls marked
5391 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5392 sibling call optimization</a> when the caller and callee have
5393 matching signatures, or 2) forced tail call optimization when the
5394 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5395 <ul>
5396 <li>Caller and callee both have the calling
5397 convention <tt>fastcc</tt>.</li>
5398 <li>The call is in tail position (ret immediately follows call and ret
5399 uses value of call or is void).</li>
5400 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5401 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5402 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5403 constraints are met.</a></li>
5404 </ul>
5405 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5406
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5407 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5408 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5409 defaults to using C calling conventions. The calling convention of the
5410 call must match the calling convention of the target function, or else the
5411 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5412
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5414 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5415 '<tt>inreg</tt>' attributes are valid here.</li>
5416
5417 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5418 type of the return value. Functions that return no value are marked
5419 <tt><a href="#t_void">void</a></tt>.</li>
5420
5421 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5422 being invoked. The argument types must match the types implied by this
5423 signature. This type can be omitted if the function is not varargs and if
5424 the function type does not return a pointer to a function.</li>
5425
5426 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5427 be invoked. In most cases, this is a direct function invocation, but
5428 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5429 to function value.</li>
5430
5431 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5432 signature argument types and parameter attributes. All arguments must be
5433 of <a href="#t_firstclass">first class</a> type. If the function
5434 signature indicates the function accepts a variable number of arguments,
5435 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436
5437 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5438 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5439 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5440</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5441
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5442<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5443<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5444 a specified function, with its incoming arguments bound to the specified
5445 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5446 function, control flow continues with the instruction after the function
5447 call, and the return value of the function is bound to the result
5448 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5449
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5450<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5451<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5452 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5453 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5454 %X = tail call i32 @foo() <i>; yields i32</i>
5455 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5456 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5457
5458 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5459 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5460 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5461 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5462 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5463 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5464</pre>
5465
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5466<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5467standard C99 library as being the C99 library functions, and may perform
5468optimizations or generate code for them under that assumption. This is
5469something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5470freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5471
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5472</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5473
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5474<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5475<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5476 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5477</div>
5478
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5479<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5480
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5481<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5482<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5483 &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]5484</pre>
5485
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5486<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5487<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5488 the "variable argument" area of a function call. It is used to implement the
5489 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5490
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5491<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5492<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5493 argument. It returns a value of the specified argument type and increments
5494 the <tt>va_list</tt> to point to the next argument. The actual type
5495 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5496
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5497<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5498<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5499 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5500 to the next argument. For more information, see the variable argument
5501 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5502
5503<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]5504 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5505 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5506
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5507<p><tt>va_arg</tt> is an LLVM instruction instead of
5508 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5509 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5510
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5511<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5512<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5513
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5514<p>Note that the code generator does not yet fully support va_arg on many
5515 targets. Also, it does not currently support va_arg with aggregate types on
5516 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5517
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5518</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5519
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5520<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5521<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5522<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5523
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5524<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5525
5526<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5527 well known names and semantics and are required to follow certain
5528 restrictions. Overall, these intrinsics represent an extension mechanism for
5529 the LLVM language that does not require changing all of the transformations
5530 in LLVM when adding to the language (or the bitcode reader/writer, the
5531 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5532
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5533<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5535 begin with this prefix. Intrinsic functions must always be external
5536 functions: you cannot define the body of intrinsic functions. Intrinsic
5537 functions may only be used in call or invoke instructions: it is illegal to
5538 take the address of an intrinsic function. Additionally, because intrinsic
5539 functions are part of the LLVM language, it is required if any are added that
5540 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5541
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5542<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5543 family of functions that perform the same operation but on different data
5544 types. Because LLVM can represent over 8 million different integer types,
5545 overloading is used commonly to allow an intrinsic function to operate on any
5546 integer type. One or more of the argument types or the result type can be
5547 overloaded to accept any integer type. Argument types may also be defined as
5548 exactly matching a previous argument's type or the result type. This allows
5549 an intrinsic function which accepts multiple arguments, but needs all of them
5550 to be of the same type, to only be overloaded with respect to a single
5551 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5552
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5553<p>Overloaded intrinsics will have the names of its overloaded argument types
5554 encoded into its function name, each preceded by a period. Only those types
5555 which are overloaded result in a name suffix. Arguments whose type is matched
5556 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5557 can take an integer of any width and returns an integer of exactly the same
5558 integer width. This leads to a family of functions such as
5559 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5560 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5561 suffix is required. Because the argument's type is matched against the return
5562 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5563
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5564<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5565 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5567</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]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_subsection">
5571 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5572</div>
5573
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5574<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5575
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576<p>Variable argument support is defined in LLVM with
5577 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5578 intrinsic functions. These functions are related to the similarly named
5579 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5580
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5581<p>All of these functions operate on arguments that use a target-specific value
5582 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5583 not define what this type is, so all transformations should be prepared to
5584 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5585
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5586<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]5587 instruction and the variable argument handling intrinsic functions are
5588 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5589
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5590<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5591<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5592define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5593 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5594 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5595 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5596 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5597
5598 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5599 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5600
5601 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5602 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5603 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5604 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5605 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5606
5607 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5608 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5609 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5610}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5611
5612declare void @llvm.va_start(i8*)
5613declare void @llvm.va_copy(i8*, i8*)
5614declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5615</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5616</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5617
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5618</div>
5619
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5620<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5621<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5622 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5623</div>
5624
5625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5626<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5628<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629<pre>
5630 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5631</pre>
5632
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5633<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5635 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]5636
5637<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5638<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]5639
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5640<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5641<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]5642 macro available in C. In a target-dependent way, it initializes
5643 the <tt>va_list</tt> element to which the argument points, so that the next
5644 call to <tt>va_arg</tt> will produce the first variable argument passed to
5645 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5646 need to know the last argument of the function as the compiler can figure
5647 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5649</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5651<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5652<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5653 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5654</div>
5655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5656<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5658<h5>Syntax:</h5>
5659<pre>
5660 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5661</pre>
5662
5663<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5664<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665 which has been initialized previously
5666 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5667 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5668
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5669<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5670<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]5671
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5672<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5673<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]5674 macro available in C. In a target-dependent way, it destroys
5675 the <tt>va_list</tt> element to which the argument points. Calls
5676 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5677 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5678 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5679
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5680</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5681
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5682<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5683<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5684 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5685</div>
5686
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5687<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5689<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5690<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5691 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5692</pre>
5693
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5694<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5695<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5696 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5697
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5698<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5699<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]5700 The second argument is a pointer to a <tt>va_list</tt> element to copy
5701 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5702
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5703<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5704<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]5705 macro available in C. In a target-dependent way, it copies the
5706 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5707 element. This intrinsic is necessary because
5708 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5709 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5711</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5712
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5713<!-- ======================================================================= -->
5714<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5716</div>
5717
5718<div class="doc_text">
5719
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5720<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5721Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5723roots on the stack</a>, as well as garbage collector implementations that
5724require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5725barriers. Front-ends for type-safe garbage collected languages should generate
5726these intrinsics to make use of the LLVM garbage collectors. For more details,
5727see <a href="GarbageCollection.html">Accurate Garbage Collection with
5728LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5729
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730<p>The garbage collection intrinsics only operate on objects in the generic
5731 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5732
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5733</div>
5734
5735<!-- _______________________________________________________________________ -->
5736<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5737 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5738</div>
5739
5740<div class="doc_text">
5741
5742<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5743<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5744 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5745</pre>
5746
5747<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5748<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]5749 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5750
5751<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5752<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5753 root pointer. The second pointer (which must be either a constant or a
5754 global value address) contains the meta-data to be associated with the
5755 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5756
5757<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5758<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]5759 location. At compile-time, the code generator generates information to allow
5760 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5761 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5762 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5763
5764</div>
5765
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5766<!-- _______________________________________________________________________ -->
5767<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5768 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5769</div>
5770
5771<div class="doc_text">
5772
5773<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5774<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5775 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5776</pre>
5777
5778<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5779<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5780 locations, allowing garbage collector implementations that require read
5781 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5782
5783<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5784<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]5785 allocated from the garbage collector. The first object is a pointer to the
5786 start of the referenced object, if needed by the language runtime (otherwise
5787 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5788
5789<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5790<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791 instruction, but may be replaced with substantially more complex code by the
5792 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5793 may only be used in a function which <a href="#gc">specifies a GC
5794 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5795
5796</div>
5797
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5806<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5807 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5808</pre>
5809
5810<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5811<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812 locations, allowing garbage collector implementations that require write
5813 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5814
5815<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5816<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]5817 object to store it to, and the third is the address of the field of Obj to
5818 store to. If the runtime does not require a pointer to the object, Obj may
5819 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5820
5821<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5822<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5823 instruction, but may be replaced with substantially more complex code by the
5824 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5825 may only be used in a function which <a href="#gc">specifies a GC
5826 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5827
5828</div>
5829
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5830<!-- ======================================================================= -->
5831<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5832 <a name="int_codegen">Code Generator Intrinsics</a>
5833</div>
5834
5835<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5836
5837<p>These intrinsics are provided by LLVM to expose special features that may
5838 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5839
5840</div>
5841
5842<!-- _______________________________________________________________________ -->
5843<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5844 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5845</div>
5846
5847<div class="doc_text">
5848
5849<h5>Syntax:</h5>
5850<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5851 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5852</pre>
5853
5854<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5856 target-specific value indicating the return address of the current function
5857 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5858
5859<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5860<p>The argument to this intrinsic indicates which function to return the address
5861 for. Zero indicates the calling function, one indicates its caller, etc.
5862 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5863
5864<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5866 indicating the return address of the specified call frame, or zero if it
5867 cannot be identified. The value returned by this intrinsic is likely to be
5868 incorrect or 0 for arguments other than zero, so it should only be used for
5869 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5870
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871<p>Note that calling this intrinsic does not prevent function inlining or other
5872 aggressive transformations, so the value returned may not be that of the
5873 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5874
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5875</div>
5876
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5877<!-- _______________________________________________________________________ -->
5878<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5879 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5880</div>
5881
5882<div class="doc_text">
5883
5884<h5>Syntax:</h5>
5885<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5886 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5887</pre>
5888
5889<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5891 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5892
5893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5894<p>The argument to this intrinsic indicates which function to return the frame
5895 pointer for. Zero indicates the calling function, one indicates its caller,
5896 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5900 indicating the frame address of the specified call frame, or zero if it
5901 cannot be identified. The value returned by this intrinsic is likely to be
5902 incorrect or 0 for arguments other than zero, so it should only be used for
5903 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5905<p>Note that calling this intrinsic does not prevent function inlining or other
5906 aggressive transformations, so the value returned may not be that of the
5907 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5908
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5909</div>
5910
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5911<!-- _______________________________________________________________________ -->
5912<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5913 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5914</div>
5915
5916<div class="doc_text">
5917
5918<h5>Syntax:</h5>
5919<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5920 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5925 of the function stack, for use
5926 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5927 useful for implementing language features like scoped automatic variable
5928 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5929
5930<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5931<p>This intrinsic returns a opaque pointer value that can be passed
5932 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5933 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5934 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5935 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5936 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5937 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5938
5939</div>
5940
5941<!-- _______________________________________________________________________ -->
5942<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5943 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5944</div>
5945
5946<div class="doc_text">
5947
5948<h5>Syntax:</h5>
5949<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5950 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5955 the function stack to the state it was in when the
5956 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5957 executed. This is useful for implementing language features like scoped
5958 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5959
5960<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961<p>See the description
5962 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5963
5964</div>
5965
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5966<!-- _______________________________________________________________________ -->
5967<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5968 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5969</div>
5970
5971<div class="doc_text">
5972
5973<h5>Syntax:</h5>
5974<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5975 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]5976</pre>
5977
5978<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5979<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5980 insert a prefetch instruction if supported; otherwise, it is a noop.
5981 Prefetches have no effect on the behavior of the program but can change its
5982 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5983
5984<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5985<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5986 specifier determining if the fetch should be for a read (0) or write (1),
5987 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5988 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5989 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5990
5991<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992<p>This intrinsic does not modify the behavior of the program. In particular,
5993 prefetches cannot trap and do not produce a value. On targets that support
5994 this intrinsic, the prefetch can provide hints to the processor cache for
5995 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5996
5997</div>
5998
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5999<!-- _______________________________________________________________________ -->
6000<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6001 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6002</div>
6003
6004<div class="doc_text">
6005
6006<h5>Syntax:</h5>
6007<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6008 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6009</pre>
6010
6011<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6013 Counter (PC) in a region of code to simulators and other tools. The method
6014 is target specific, but it is expected that the marker will use exported
6015 symbols to transmit the PC of the marker. The marker makes no guarantees
6016 that it will remain with any specific instruction after optimizations. It is
6017 possible that the presence of a marker will inhibit optimizations. The
6018 intended use is to be inserted after optimizations to allow correlations of
6019 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6020
6021<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6022<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6023
6024<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6025<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6026 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6027
6028</div>
6029
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
6031<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6032 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6033</div>
6034
6035<div class="doc_text">
6036
6037<h5>Syntax:</h5>
6038<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6039 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6040</pre>
6041
6042<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6044 counter register (or similar low latency, high accuracy clocks) on those
6045 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6046 should map to RPCC. As the backing counters overflow quickly (on the order
6047 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6048
6049<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050<p>When directly supported, reading the cycle counter should not modify any
6051 memory. Implementations are allowed to either return a application specific
6052 value or a system wide value. On backends without support, this is lowered
6053 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6054
6055</div>
6056
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6057<!-- ======================================================================= -->
6058<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6059 <a name="int_libc">Standard C Library Intrinsics</a>
6060</div>
6061
6062<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6063
6064<p>LLVM provides intrinsics for a few important standard C library functions.
6065 These intrinsics allow source-language front-ends to pass information about
6066 the alignment of the pointer arguments to the code generator, providing
6067 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6068
6069</div>
6070
6071<!-- _______________________________________________________________________ -->
6072<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6073 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6074</div>
6075
6076<div class="doc_text">
6077
6078<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6079<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]6080 integer bit width and for different address spaces. Not all targets support
6081 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6082
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6083<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6084 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6085 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6086 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6087 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6088</pre>
6089
6090<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6091<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6092 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6093
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6094<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6095 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6096 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6097
6098<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6100<p>The first argument is a pointer to the destination, the second is a pointer
6101 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6102 number of bytes to copy, the fourth argument is the alignment of the
6103 source and destination locations, and the fifth is a boolean indicating a
6104 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6105
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6106<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]6107 then the caller guarantees that both the source and destination pointers are
6108 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6109
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6110<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6111 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6112 The detailed access behavior is not very cleanly specified and it is unwise
6113 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6114
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6115<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6117<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6118 source location to the destination location, which are not allowed to
6119 overlap. It copies "len" bytes of memory over. If the argument is known to
6120 be aligned to some boundary, this can be specified as the fourth argument,
6121 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6122
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6123</div>
6124
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6125<!-- _______________________________________________________________________ -->
6126<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6127 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128</div>
6129
6130<div class="doc_text">
6131
6132<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6133<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]6134 width and for different address space. Not all targets support all bit
6135 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6137<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6138 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6139 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6140 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6141 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6142</pre>
6143
6144<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6145<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6146 source location to the destination location. It is similar to the
6147 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6148 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6150<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6151 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6152 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6153
6154<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6156<p>The first argument is a pointer to the destination, the second is a pointer
6157 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6158 number of bytes to copy, the fourth argument is the alignment of the
6159 source and destination locations, and the fifth is a boolean indicating a
6160 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6161
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6162<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]6163 then the caller guarantees that the source and destination pointers are
6164 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6165
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6166<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6167 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6168 The detailed access behavior is not very cleanly specified and it is unwise
6169 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6170
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6171<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6172
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6174 source location to the destination location, which may overlap. It copies
6175 "len" bytes of memory over. If the argument is known to be aligned to some
6176 boundary, this can be specified as the fourth argument, otherwise it should
6177 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6178
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6179</div>
6180
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6181<!-- _______________________________________________________________________ -->
6182<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6183 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6184</div>
6185
6186<div class="doc_text">
6187
6188<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6189<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]6190 width and for different address spaces. Not all targets support all bit
6191 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6192
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6193<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6194 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6195 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6196 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6197 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +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.memset.*</tt>' intrinsics fill a block of memory with a
6202 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6204<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6205 intrinsic does not return a value, takes extra alignment/volatile arguments,
6206 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6207
6208<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209<p>The first argument is a pointer to the destination to fill, the second is the
6210 byte value to fill it with, the third argument is an integer argument
6211 specifying the number of bytes to fill, and the fourth argument is the known
6212 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6213
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6214<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]6215 then the caller guarantees that the destination pointer is aligned to that
6216 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6217
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6218<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6219 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6220 The detailed access behavior is not very cleanly specified and it is unwise
6221 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6222
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6223<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6224<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6225 at the destination location. If the argument is known to be aligned to some
6226 boundary, this can be specified as the fourth argument, otherwise it should
6227 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6228
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6229</div>
6230
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6231<!-- _______________________________________________________________________ -->
6232<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6233 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6234</div>
6235
6236<div class="doc_text">
6237
6238<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6240 floating point or vector of floating point type. Not all targets support all
6241 types however.</p>
6242
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6243<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6244 declare float @llvm.sqrt.f32(float %Val)
6245 declare double @llvm.sqrt.f64(double %Val)
6246 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6247 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6248 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6249</pre>
6250
6251<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6252<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6253 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6254 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6255 behavior for negative numbers other than -0.0 (which allows for better
6256 optimization, because there is no need to worry about errno being
6257 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]6258
6259<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6260<p>The argument and return value are floating point numbers of the same
6261 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6262
6263<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6264<p>This function returns the sqrt of the specified operand if it is a
6265 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6266
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6267</div>
6268
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6269<!-- _______________________________________________________________________ -->
6270<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6271 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6272</div>
6273
6274<div class="doc_text">
6275
6276<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6277<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6278 floating point or vector of floating point type. Not all targets support all
6279 types however.</p>
6280
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6281<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6282 declare float @llvm.powi.f32(float %Val, i32 %power)
6283 declare double @llvm.powi.f64(double %Val, i32 %power)
6284 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6285 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6286 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6287</pre>
6288
6289<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6290<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6291 specified (positive or negative) power. The order of evaluation of
6292 multiplications is not defined. When a vector of floating point type is
6293 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6294
6295<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6296<p>The second argument is an integer power, and the first is a value to raise to
6297 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6298
6299<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6300<p>This function returns the first value raised to the second power with an
6301 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6302
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6303</div>
6304
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6305<!-- _______________________________________________________________________ -->
6306<div class="doc_subsubsection">
6307 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6308</div>
6309
6310<div class="doc_text">
6311
6312<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6313<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6314 floating point or vector of floating point type. Not all targets support all
6315 types however.</p>
6316
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6317<pre>
6318 declare float @llvm.sin.f32(float %Val)
6319 declare double @llvm.sin.f64(double %Val)
6320 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6321 declare fp128 @llvm.sin.f128(fp128 %Val)
6322 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6323</pre>
6324
6325<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6326<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6327
6328<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6329<p>The argument and return value are floating point numbers of the same
6330 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6331
6332<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6333<p>This function returns the sine of the specified operand, returning the same
6334 values as the libm <tt>sin</tt> functions would, and handles error conditions
6335 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6336
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6337</div>
6338
6339<!-- _______________________________________________________________________ -->
6340<div class="doc_subsubsection">
6341 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6342</div>
6343
6344<div class="doc_text">
6345
6346<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6348 floating point or vector of floating point type. Not all targets support all
6349 types however.</p>
6350
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6351<pre>
6352 declare float @llvm.cos.f32(float %Val)
6353 declare double @llvm.cos.f64(double %Val)
6354 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6355 declare fp128 @llvm.cos.f128(fp128 %Val)
6356 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6357</pre>
6358
6359<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6360<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6361
6362<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6363<p>The argument and return value are floating point numbers of the same
6364 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6365
6366<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6367<p>This function returns the cosine of the specified operand, returning the same
6368 values as the libm <tt>cos</tt> functions would, and handles error conditions
6369 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6370
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6371</div>
6372
6373<!-- _______________________________________________________________________ -->
6374<div class="doc_subsubsection">
6375 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6376</div>
6377
6378<div class="doc_text">
6379
6380<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6381<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6382 floating point or vector of floating point type. Not all targets support all
6383 types however.</p>
6384
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6385<pre>
6386 declare float @llvm.pow.f32(float %Val, float %Power)
6387 declare double @llvm.pow.f64(double %Val, double %Power)
6388 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6389 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6390 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6391</pre>
6392
6393<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6394<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6395 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6396
6397<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6398<p>The second argument is a floating point power, and the first is a value to
6399 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6400
6401<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6402<p>This function returns the first value raised to the second power, returning
6403 the same values as the libm <tt>pow</tt> functions would, and handles error
6404 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6405
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6406</div>
6407
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6408<!-- ======================================================================= -->
6409<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6410 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6411</div>
6412
6413<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6414
6415<p>LLVM provides intrinsics for a few important bit manipulation operations.
6416 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6417
6418</div>
6419
6420<!-- _______________________________________________________________________ -->
6421<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6422 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6423</div>
6424
6425<div class="doc_text">
6426
6427<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6428<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6429 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6430
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6431<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6432 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6433 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6434 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6435</pre>
6436
6437<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6438<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6439 values with an even number of bytes (positive multiple of 16 bits). These
6440 are useful for performing operations on data that is not in the target's
6441 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6442
6443<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6444<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6445 and low byte of the input i16 swapped. Similarly,
6446 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6447 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6448 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6449 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6450 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6451 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6452
6453</div>
6454
6455<!-- _______________________________________________________________________ -->
6456<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6457 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6458</div>
6459
6460<div class="doc_text">
6461
6462<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6463<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]6464 width. Not all targets support all bit widths however.</p>
6465
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6466<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6467 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6468 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6469 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6470 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6471 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6472</pre>
6473
6474<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6475<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6476 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6477
6478<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6479<p>The only argument is the value to be counted. The argument may be of any
6480 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6481
6482<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6483<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]6484
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6485</div>
6486
6487<!-- _______________________________________________________________________ -->
6488<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6489 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6490</div>
6491
6492<div class="doc_text">
6493
6494<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6495<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6496 integer bit width. Not all targets support all bit widths however.</p>
6497
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6498<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6499 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6500 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6501 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6502 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6503 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6504</pre>
6505
6506<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6507<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6508 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6509
6510<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6511<p>The only argument is the value to be counted. The argument may be of any
6512 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6513
6514<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6515<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6516 zeros in a variable. If the src == 0 then the result is the size in bits of
6517 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6518
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6519</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6520
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6521<!-- _______________________________________________________________________ -->
6522<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6523 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6524</div>
6525
6526<div class="doc_text">
6527
6528<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6529<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6530 integer bit width. Not all targets support all bit widths however.</p>
6531
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6532<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6533 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6534 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6535 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6536 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6537 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6538</pre>
6539
6540<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6541<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6542 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6543
6544<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6545<p>The only argument is the value to be counted. The argument may be of any
6546 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6547
6548<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6549<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6550 zeros in a variable. If the src == 0 then the result is the size in bits of
6551 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6552
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6553</div>
6554
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6555<!-- ======================================================================= -->
6556<div class="doc_subsection">
6557 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6558</div>
6559
6560<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6561
6562<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6563
6564</div>
6565
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6566<!-- _______________________________________________________________________ -->
6567<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6568 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6569</div>
6570
6571<div class="doc_text">
6572
6573<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6574<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]6575 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6576
6577<pre>
6578 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6579 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6580 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6581</pre>
6582
6583<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6584<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585 a signed addition of the two arguments, and indicate whether an overflow
6586 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587
6588<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6589<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]6590 be of integer types of any bit width, but they must have the same bit
6591 width. The second element of the result structure must be of
6592 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6593 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6594
6595<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6596<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6597 a signed addition of the two variables. They return a structure &mdash; the
6598 first element of which is the signed summation, and the second element of
6599 which is a bit specifying if the signed summation resulted in an
6600 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6601
6602<h5>Examples:</h5>
6603<pre>
6604 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6605 %sum = extractvalue {i32, i1} %res, 0
6606 %obit = extractvalue {i32, i1} %res, 1
6607 br i1 %obit, label %overflow, label %normal
6608</pre>
6609
6610</div>
6611
6612<!-- _______________________________________________________________________ -->
6613<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6614 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6615</div>
6616
6617<div class="doc_text">
6618
6619<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6620<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]6621 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6622
6623<pre>
6624 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6625 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6626 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6627</pre>
6628
6629<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6630<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631 an unsigned addition of the two arguments, and indicate whether a carry
6632 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6633
6634<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6635<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]6636 be of integer types of any bit width, but they must have the same bit
6637 width. The second element of the result structure must be of
6638 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6639 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6640
6641<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6642<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643 an unsigned addition of the two arguments. They return a structure &mdash;
6644 the first element of which is the sum, and the second element of which is a
6645 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6646
6647<h5>Examples:</h5>
6648<pre>
6649 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6650 %sum = extractvalue {i32, i1} %res, 0
6651 %obit = extractvalue {i32, i1} %res, 1
6652 br i1 %obit, label %carry, label %normal
6653</pre>
6654
6655</div>
6656
6657<!-- _______________________________________________________________________ -->
6658<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6659 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6660</div>
6661
6662<div class="doc_text">
6663
6664<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6665<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]6666 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6667
6668<pre>
6669 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6670 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6671 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6672</pre>
6673
6674<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6675<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6676 a signed subtraction of the two arguments, and indicate whether an overflow
6677 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6678
6679<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6680<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]6681 be of integer types of any bit width, but they must have the same bit
6682 width. The second element of the result structure must be of
6683 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6684 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6685
6686<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6687<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6688 a signed subtraction of the two arguments. They return a structure &mdash;
6689 the first element of which is the subtraction, and the second element of
6690 which is a bit specifying if the signed subtraction resulted in an
6691 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<h5>Examples:</h5>
6694<pre>
6695 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6696 %sum = extractvalue {i32, i1} %res, 0
6697 %obit = extractvalue {i32, i1} %res, 1
6698 br i1 %obit, label %overflow, label %normal
6699</pre>
6700
6701</div>
6702
6703<!-- _______________________________________________________________________ -->
6704<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6705 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6706</div>
6707
6708<div class="doc_text">
6709
6710<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6711<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]6712 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6713
6714<pre>
6715 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6716 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6717 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6718</pre>
6719
6720<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6721<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722 an unsigned subtraction of the two arguments, and indicate whether an
6723 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6724
6725<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6726<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]6727 be of integer types of any bit width, but they must have the same bit
6728 width. The second element of the result structure must be of
6729 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6730 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6731
6732<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6733<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6734 an unsigned subtraction of the two arguments. They return a structure &mdash;
6735 the first element of which is the subtraction, and the second element of
6736 which is a bit specifying if the unsigned subtraction resulted in an
6737 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6738
6739<h5>Examples:</h5>
6740<pre>
6741 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6742 %sum = extractvalue {i32, i1} %res, 0
6743 %obit = extractvalue {i32, i1} %res, 1
6744 br i1 %obit, label %overflow, label %normal
6745</pre>
6746
6747</div>
6748
6749<!-- _______________________________________________________________________ -->
6750<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6751 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6752</div>
6753
6754<div class="doc_text">
6755
6756<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6757<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]6758 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6759
6760<pre>
6761 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6762 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6763 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6764</pre>
6765
6766<h5>Overview:</h5>
6767
6768<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6769 a signed multiplication of the two arguments, and indicate whether an
6770 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6771
6772<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6773<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]6774 be of integer types of any bit width, but they must have the same bit
6775 width. The second element of the result structure must be of
6776 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6777 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6778
6779<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6780<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6781 a signed multiplication of the two arguments. They return a structure &mdash;
6782 the first element of which is the multiplication, and the second element of
6783 which is a bit specifying if the signed multiplication resulted in an
6784 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6785
6786<h5>Examples:</h5>
6787<pre>
6788 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6789 %sum = extractvalue {i32, i1} %res, 0
6790 %obit = extractvalue {i32, i1} %res, 1
6791 br i1 %obit, label %overflow, label %normal
6792</pre>
6793
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6794</div>
6795
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6796<!-- _______________________________________________________________________ -->
6797<div class="doc_subsubsection">
6798 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6799</div>
6800
6801<div class="doc_text">
6802
6803<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6804<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]6805 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6806
6807<pre>
6808 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6809 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6810 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6811</pre>
6812
6813<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6814<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6815 a unsigned multiplication of the two arguments, and indicate whether an
6816 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6817
6818<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6819<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]6820 be of integer types of any bit width, but they must have the same bit
6821 width. The second element of the result structure must be of
6822 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6823 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6824
6825<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6826<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6827 an unsigned multiplication of the two arguments. They return a structure
6828 &mdash; the first element of which is the multiplication, and the second
6829 element of which is a bit specifying if the unsigned multiplication resulted
6830 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6831
6832<h5>Examples:</h5>
6833<pre>
6834 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6835 %sum = extractvalue {i32, i1} %res, 0
6836 %obit = extractvalue {i32, i1} %res, 1
6837 br i1 %obit, label %overflow, label %normal
6838</pre>
6839
6840</div>
6841
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6842<!-- ======================================================================= -->
6843<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6844 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6845</div>
6846
6847<div class="doc_text">
6848
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6849<p>Half precision floating point is a storage-only format. This means that it is
6850 a dense encoding (in memory) but does not support computation in the
6851 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6852
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6853<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6854 value as an i16, then convert it to float with <a
6855 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6856 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6857 double etc). To store the value back to memory, it is first converted to
6858 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6859 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6860 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6861</div>
6862
6863<!-- _______________________________________________________________________ -->
6864<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6865 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6866</div>
6867
6868<div class="doc_text">
6869
6870<h5>Syntax:</h5>
6871<pre>
6872 declare i16 @llvm.convert.to.fp16(f32 %a)
6873</pre>
6874
6875<h5>Overview:</h5>
6876<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6877 a conversion from single precision floating point format to half precision
6878 floating point format.</p>
6879
6880<h5>Arguments:</h5>
6881<p>The intrinsic function contains single argument - the value to be
6882 converted.</p>
6883
6884<h5>Semantics:</h5>
6885<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6886 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6887 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6888 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6889
6890<h5>Examples:</h5>
6891<pre>
6892 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6893 store i16 %res, i16* @x, align 2
6894</pre>
6895
6896</div>
6897
6898<!-- _______________________________________________________________________ -->
6899<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6900 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6901</div>
6902
6903<div class="doc_text">
6904
6905<h5>Syntax:</h5>
6906<pre>
6907 declare f32 @llvm.convert.from.fp16(i16 %a)
6908</pre>
6909
6910<h5>Overview:</h5>
6911<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6912 a conversion from half precision floating point format to single precision
6913 floating point format.</p>
6914
6915<h5>Arguments:</h5>
6916<p>The intrinsic function contains single argument - the value to be
6917 converted.</p>
6918
6919<h5>Semantics:</h5>
6920<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6921 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6922 precision floating point format. The input half-float value is represented by
6923 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6924
6925<h5>Examples:</h5>
6926<pre>
6927 %a = load i16* @x, align 2
6928 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6929</pre>
6930
6931</div>
6932
6933<!-- ======================================================================= -->
6934<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6935 <a name="int_debugger">Debugger Intrinsics</a>
6936</div>
6937
6938<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6941 prefix), are described in
6942 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6943 Level Debugging</a> document.</p>
6944
6945</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6946
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6947<!-- ======================================================================= -->
6948<div class="doc_subsection">
6949 <a name="int_eh">Exception Handling Intrinsics</a>
6950</div>
6951
6952<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953
6954<p>The LLVM exception handling intrinsics (which all start with
6955 <tt>llvm.eh.</tt> prefix), are described in
6956 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6957 Handling</a> document.</p>
6958
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6959</div>
6960
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6961<!-- ======================================================================= -->
6962<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6963 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6964</div>
6965
6966<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6967
6968<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6969 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6970 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6971 function pointer lacking the nest parameter - the caller does not need to
6972 provide a value for it. Instead, the value to use is stored in advance in a
6973 "trampoline", a block of memory usually allocated on the stack, which also
6974 contains code to splice the nest value into the argument list. This is used
6975 to implement the GCC nested function address extension.</p>
6976
6977<p>For example, if the function is
6978 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6979 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6980 follows:</p>
6981
6982<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6983<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6984 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6985 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6986 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6987 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6988</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6989</div>
6990
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6991<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6992 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6994</div>
6995
6996<!-- _______________________________________________________________________ -->
6997<div class="doc_subsubsection">
6998 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6999</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7001<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7003<h5>Syntax:</h5>
7004<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7005 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]7006</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7007
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7008<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7009<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
7010 function pointer suitable for executing it.</p>
7011
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7012<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7013<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7014 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7015 sufficiently aligned block of memory; this memory is written to by the
7016 intrinsic. Note that the size and the alignment are target-specific - LLVM
7017 currently provides no portable way of determining them, so a front-end that
7018 generates this intrinsic needs to have some target-specific knowledge.
7019 The <tt>func</tt> argument must hold a function bitcast to
7020 an <tt>i8*</tt>.</p>
7021
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7022<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7023<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7024 dependent code, turning it into a function. A pointer to this function is
7025 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7026 function pointer type</a> before being called. The new function's signature
7027 is the same as that of <tt>func</tt> with any arguments marked with
7028 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7029 is allowed, and it must be of pointer type. Calling the new function is
7030 equivalent to calling <tt>func</tt> with the same argument list, but
7031 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7032 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7033 by <tt>tramp</tt> is modified, then the effect of any later call to the
7034 returned function pointer is undefined.</p>
7035
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7036</div>
7037
7038<!-- ======================================================================= -->
7039<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7040 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7041</div>
7042
7043<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7044
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7045<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7046 hardware constructs for atomic operations and memory synchronization. This
7047 provides an interface to the hardware, not an interface to the programmer. It
7048 is aimed at a low enough level to allow any programming models or APIs
7049 (Application Programming Interfaces) which need atomic behaviors to map
7050 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7051 hardware provides a "universal IR" for source languages, it also provides a
7052 starting point for developing a "universal" atomic operation and
7053 synchronization IR.</p>
7054
7055<p>These do <em>not</em> form an API such as high-level threading libraries,
7056 software transaction memory systems, atomic primitives, and intrinsic
7057 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7058 application libraries. The hardware interface provided by LLVM should allow
7059 a clean implementation of all of these APIs and parallel programming models.
7060 No one model or paradigm should be selected above others unless the hardware
7061 itself ubiquitously does so.</p>
7062
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7063</div>
7064
7065<!-- _______________________________________________________________________ -->
7066<div class="doc_subsubsection">
7067 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7068</div>
7069<div class="doc_text">
7070<h5>Syntax:</h5>
7071<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7072 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]7073</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7075<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7077 specific pairs of memory access types.</p>
7078
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7079<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7081 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7082 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7083 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7085<ul>
7086 <li><tt>ll</tt>: load-load barrier</li>
7087 <li><tt>ls</tt>: load-store barrier</li>
7088 <li><tt>sl</tt>: store-load barrier</li>
7089 <li><tt>ss</tt>: store-store barrier</li>
7090 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7091</ul>
7092
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7093<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7094<p>This intrinsic causes the system to enforce some ordering constraints upon
7095 the loads and stores of the program. This barrier does not
7096 indicate <em>when</em> any events will occur, it only enforces
7097 an <em>order</em> in which they occur. For any of the specified pairs of load
7098 and store operations (f.ex. load-load, or store-load), all of the first
7099 operations preceding the barrier will complete before any of the second
7100 operations succeeding the barrier begin. Specifically the semantics for each
7101 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7102
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7103<ul>
7104 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7105 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7106 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7107 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7108 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7109 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7110 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7111 load after the barrier begins.</li>
7112</ul>
7113
7114<p>These semantics are applied with a logical "and" behavior when more than one
7115 is enabled in a single memory barrier intrinsic.</p>
7116
7117<p>Backends may implement stronger barriers than those requested when they do
7118 not support as fine grained a barrier as requested. Some architectures do
7119 not need all types of barriers and on such architectures, these become
7120 noops.</p>
7121
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7122<h5>Example:</h5>
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 Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7126 store i32 4, %ptr
7127
7128%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7129 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7130 <i>; guarantee the above finishes</i>
7131 store i32 8, %ptr <i>; before this begins</i>
7132</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7133
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7134</div>
7135
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136<!-- _______________________________________________________________________ -->
7137<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7138 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7140
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7141<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7142
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7143<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7144<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7145 any integer bit width and for different address spaces. Not all targets
7146 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7147
7148<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7149 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7150 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7151 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7152 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]7153</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7154
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7155<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7156<p>This loads a value in memory and compares it to a given value. If they are
7157 equal, it stores a new value into the memory.</p>
7158
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7161 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7162 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7163 this integer type. While any bit width integer may be used, targets may only
7164 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>This entire intrinsic must be executed atomically. It first loads the value
7168 in memory pointed to by <tt>ptr</tt> and compares it with the
7169 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7170 memory. The loaded value is yielded in all cases. This provides the
7171 equivalent of an atomic compare-and-swap operation within the SSA
7172 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7173
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7176%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7177%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7178 store i32 4, %ptr
7179
7180%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7181%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7182 <i>; yields {i32}:result1 = 4</i>
7183%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7184%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7185
7186%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7187%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7188 <i>; yields {i32}:result2 = 8</i>
7189%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7190
7191%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7192</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7194</div>
7195
7196<!-- _______________________________________________________________________ -->
7197<div class="doc_subsubsection">
7198 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7199</div>
7200<div class="doc_text">
7201<h5>Syntax:</h5>
7202
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7204 integer bit width. Not all targets support all bit widths however.</p>
7205
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7207 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7208 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7209 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7210 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]7211</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7213<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7214<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7215 the value from memory. It then stores the value in <tt>val</tt> in the memory
7216 at <tt>ptr</tt>.</p>
7217
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7218<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7220 the <tt>val</tt> argument and the result must be integers of the same bit
7221 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7222 integer type. The targets may only lower integer representations they
7223 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7224
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7225<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7226<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7227 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7228 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7229
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7230<h5>Examples:</h5>
7231<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7232%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7233%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7234 store i32 4, %ptr
7235
7236%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7237%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7238 <i>; yields {i32}:result1 = 4</i>
7239%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7240%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7241
7242%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7243%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7244 <i>; yields {i32}:result2 = 8</i>
7245
7246%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7247%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7248</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7249
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7250</div>
7251
7252<!-- _______________________________________________________________________ -->
7253<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7254 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7255
7256</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7258<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7259
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7260<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7262 any integer bit width. Not all targets support all bit widths however.</p>
7263
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7264<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7265 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7266 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7267 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7268 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]7269</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7270
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7271<h5>Overview:</h5>
7272<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7273 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7274
7275<h5>Arguments:</h5>
7276<p>The intrinsic takes two arguments, the first a pointer to an integer value
7277 and the second an integer value. The result is also an integer value. These
7278 integer types can have any bit width, but they must all have the same bit
7279 width. The targets may only lower integer representations they support.</p>
7280
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7281<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7282<p>This intrinsic does a series of operations atomically. It first loads the
7283 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7284 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]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 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7291%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7292 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7293%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7294 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7295%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7296 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7297%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7300</div>
7301
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7302<!-- _______________________________________________________________________ -->
7303<div class="doc_subsubsection">
7304 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7305
7306</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7308<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7309
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7310<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7312 any integer bit width and for different address spaces. Not all targets
7313 support all bit widths however.</p>
7314
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7315<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7316 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7317 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7318 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7319 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]7320</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7321
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7322<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7323<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7324 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7325
7326<h5>Arguments:</h5>
7327<p>The intrinsic takes two arguments, the first a pointer to an integer value
7328 and the second an integer value. The result is also an integer value. These
7329 integer types can have any bit width, but they must all have the same bit
7330 width. The targets may only lower integer representations they support.</p>
7331
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7332<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7333<p>This intrinsic does a series of operations atomically. It first loads the
7334 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7335 result to <tt>ptr</tt>. It yields the original value stored
7336 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7337
7338<h5>Examples:</h5>
7339<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7340%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7341%ptr = bitcast i8* %mallocP to i32*
7342 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7343%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7344 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7345%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7347%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7348 <i>; yields {i32}:result3 = 2</i>
7349%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7350</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7351
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7352</div>
7353
7354<!-- _______________________________________________________________________ -->
7355<div class="doc_subsubsection">
7356 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7357 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7358 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7359 <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]7360</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7361
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7362<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7363
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7364<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7365<p>These are overloaded intrinsics. You can
7366 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7367 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7368 bit width and for different address spaces. Not all targets support all bit
7369 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7371<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7372 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7373 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7374 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7375 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]7376</pre>
7377
7378<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7379 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7380 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7381 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7382 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]7383</pre>
7384
7385<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7386 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7387 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7388 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7389 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]7390</pre>
7391
7392<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7393 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7394 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7395 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7396 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]7397</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7398
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7399<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7400<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7401 the value stored in memory at <tt>ptr</tt>. It yields the original value
7402 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7403
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7404<h5>Arguments:</h5>
7405<p>These intrinsics take two arguments, the first a pointer to an integer value
7406 and the second an integer value. The result is also an integer value. These
7407 integer types can have any bit width, but they must all have the same bit
7408 width. The targets may only lower integer representations they support.</p>
7409
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7411<p>These intrinsics does a series of operations atomically. They first load the
7412 value stored at <tt>ptr</tt>. They then do the bitwise
7413 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7414 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7415
7416<h5>Examples:</h5>
7417<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7418%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7419%ptr = bitcast i8* %mallocP to i32*
7420 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7421%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7422 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7423%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7424 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7425%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7426 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7427%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7428 <i>; yields {i32}:result3 = FF</i>
7429%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7430</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7431
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7432</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7433
7434<!-- _______________________________________________________________________ -->
7435<div class="doc_subsubsection">
7436 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7437 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7438 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7439 <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]7440</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7441
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7442<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7443
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7444<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7445<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7446 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7447 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7448 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7449
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7450<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7451 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7452 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7453 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7454 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]7455</pre>
7456
7457<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7458 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7459 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7460 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7461 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]7462</pre>
7463
7464<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7465 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7466 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7467 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7468 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]7469</pre>
7470
7471<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7472 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7473 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7474 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7475 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]7476</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7477
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7478<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7479<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7480 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7481 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7482
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7483<h5>Arguments:</h5>
7484<p>These intrinsics take two arguments, the first a pointer to an integer value
7485 and the second an integer value. The result is also an integer value. These
7486 integer types can have any bit width, but they must all have the same bit
7487 width. The targets may only lower integer representations they support.</p>
7488
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7489<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7490<p>These intrinsics does a series of operations atomically. They first load the
7491 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7492 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7493 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7494
7495<h5>Examples:</h5>
7496<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7497%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7498%ptr = bitcast i8* %mallocP to i32*
7499 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7500%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7501 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7502%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7503 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7504%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7505 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7506%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7507 <i>; yields {i32}:result3 = 8</i>
7508%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7509</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7510
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7511</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7512
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7513
7514<!-- ======================================================================= -->
7515<div class="doc_subsection">
7516 <a name="int_memorymarkers">Memory Use Markers</a>
7517</div>
7518
7519<div class="doc_text">
7520
7521<p>This class of intrinsics exists to information about the lifetime of memory
7522 objects and ranges where variables are immutable.</p>
7523
7524</div>
7525
7526<!-- _______________________________________________________________________ -->
7527<div class="doc_subsubsection">
7528 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7529</div>
7530
7531<div class="doc_text">
7532
7533<h5>Syntax:</h5>
7534<pre>
7535 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7536</pre>
7537
7538<h5>Overview:</h5>
7539<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7540 object's lifetime.</p>
7541
7542<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7543<p>The first argument is a constant integer representing the size of the
7544 object, or -1 if it is variable sized. The second argument is a pointer to
7545 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7546
7547<h5>Semantics:</h5>
7548<p>This intrinsic indicates that before this point in the code, the value of the
7549 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]7550 never be used and has an undefined value. A load from the pointer that
7551 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7552 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7553
7554</div>
7555
7556<!-- _______________________________________________________________________ -->
7557<div class="doc_subsubsection">
7558 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7559</div>
7560
7561<div class="doc_text">
7562
7563<h5>Syntax:</h5>
7564<pre>
7565 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7566</pre>
7567
7568<h5>Overview:</h5>
7569<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7570 object's lifetime.</p>
7571
7572<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7573<p>The first argument is a constant integer representing the size of the
7574 object, or -1 if it is variable sized. The second argument is a pointer to
7575 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7576
7577<h5>Semantics:</h5>
7578<p>This intrinsic indicates that after this point in the code, the value of the
7579 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7580 never be used and has an undefined value. Any stores into the memory object
7581 following this intrinsic may be removed as dead.
7582
7583</div>
7584
7585<!-- _______________________________________________________________________ -->
7586<div class="doc_subsubsection">
7587 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7588</div>
7589
7590<div class="doc_text">
7591
7592<h5>Syntax:</h5>
7593<pre>
7594 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7595</pre>
7596
7597<h5>Overview:</h5>
7598<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7599 a memory object will not change.</p>
7600
7601<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7602<p>The first argument is a constant integer representing the size of the
7603 object, or -1 if it is variable sized. The second argument is a pointer to
7604 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7605
7606<h5>Semantics:</h5>
7607<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7608 the return value, the referenced memory location is constant and
7609 unchanging.</p>
7610
7611</div>
7612
7613<!-- _______________________________________________________________________ -->
7614<div class="doc_subsubsection">
7615 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7616</div>
7617
7618<div class="doc_text">
7619
7620<h5>Syntax:</h5>
7621<pre>
7622 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7623</pre>
7624
7625<h5>Overview:</h5>
7626<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7627 a memory object are mutable.</p>
7628
7629<h5>Arguments:</h5>
7630<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7631 The second argument is a constant integer representing the size of the
7632 object, or -1 if it is variable sized and the third argument is a pointer
7633 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7634
7635<h5>Semantics:</h5>
7636<p>This intrinsic indicates that the memory is mutable again.</p>
7637
7638</div>
7639
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7640<!-- ======================================================================= -->
7641<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7642 <a name="int_general">General Intrinsics</a>
7643</div>
7644
7645<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7646
7647<p>This class of intrinsics is designed to be generic and has no specific
7648 purpose.</p>
7649
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7650</div>
7651
7652<!-- _______________________________________________________________________ -->
7653<div class="doc_subsubsection">
7654 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7655</div>
7656
7657<div class="doc_text">
7658
7659<h5>Syntax:</h5>
7660<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7661 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]7662</pre>
7663
7664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7666
7667<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7668<p>The first argument is a pointer to a value, the second is a pointer to a
7669 global string, the third is a pointer to a global string which is the source
7670 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7671
7672<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7673<p>This intrinsic allows annotation of local variables with arbitrary strings.
7674 This can be useful for special purpose optimizations that want to look for
7675 these annotations. These have no other defined use, they are ignored by code
7676 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7677
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7678</div>
7679
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7680<!-- _______________________________________________________________________ -->
7681<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7682 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7683</div>
7684
7685<div class="doc_text">
7686
7687<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7689 any integer bit width.</p>
7690
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7691<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7692 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7693 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7694 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7695 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7696 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]7697</pre>
7698
7699<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7700<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7701
7702<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7703<p>The first argument is an integer value (result of some expression), the
7704 second is a pointer to a global string, the third is a pointer to a global
7705 string which is the source file name, and the last argument is the line
7706 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7707
7708<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7709<p>This intrinsic allows annotations to be put on arbitrary expressions with
7710 arbitrary strings. This can be useful for special purpose optimizations that
7711 want to look for these annotations. These have no other defined use, they
7712 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7713
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7714</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7715
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7716<!-- _______________________________________________________________________ -->
7717<div class="doc_subsubsection">
7718 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7719</div>
7720
7721<div class="doc_text">
7722
7723<h5>Syntax:</h5>
7724<pre>
7725 declare void @llvm.trap()
7726</pre>
7727
7728<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7729<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7730
7731<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7732<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7733
7734<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7735<p>This intrinsics is lowered to the target dependent trap instruction. If the
7736 target does not have a trap instruction, this intrinsic will be lowered to
7737 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7738
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7739</div>
7740
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7741<!-- _______________________________________________________________________ -->
7742<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7743 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7744</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7745
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7746<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7747
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7748<h5>Syntax:</h5>
7749<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7750 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7751</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7752
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7753<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7754<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7755 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7756 ensure that it is placed on the stack before local variables.</p>
7757
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7758<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7759<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7760 arguments. The first argument is the value loaded from the stack
7761 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7762 that has enough space to hold the value of the guard.</p>
7763
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7764<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7765<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7766 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7767 stack. This is to ensure that if a local variable on the stack is
7768 overwritten, it will destroy the value of the guard. When the function exits,
7769 the guard on the stack is checked against the original guard. If they're
7770 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7771 function.</p>
7772
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7773</div>
7774
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7775<!-- _______________________________________________________________________ -->
7776<div class="doc_subsubsection">
7777 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7778</div>
7779
7780<div class="doc_text">
7781
7782<h5>Syntax:</h5>
7783<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7784 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7785 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7786</pre>
7787
7788<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7789<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7790 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7791 operation like memcpy will either overflow a buffer that corresponds to
7792 an object, or b) to determine that a runtime check for overflow isn't
7793 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7794 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7795
7796<h5>Arguments:</h5>
7797<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7798 argument is a pointer to or into the <tt>object</tt>. The second argument
7799 is a boolean 0 or 1. This argument determines whether you want the
7800 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7801 1, variables are not allowed.</p>
7802
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7803<h5>Semantics:</h5>
7804<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7805 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7806 (depending on the <tt>type</tt> argument if the size cannot be determined
7807 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7808
7809</div>
7810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7811<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7812<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7813<address>
7814 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7818
7819 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7820 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7821 Last modified: $Date$
7822</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7823
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7824</body>
7825</html>