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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 489b29b0a4ee4526e3d50ad88d3d48745baf5042 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
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
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]389<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]391
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]392<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%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]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
477<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
478<!-- *********************************************************************** -->
479
480<!-- ======================================================================= -->
481<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
482</div>
483
484<div class="doc_text">
485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]486<p>LLVM programs are composed of "Module"s, each of which is a translation unit
487 of the input programs. Each module consists of functions, global variables,
488 and symbol table entries. Modules may be combined together with the LLVM
489 linker, which merges function (and global variable) definitions, resolves
490 forward declarations, and merges symbol table entries. Here is an example of
491 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]492
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]493<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]494<i>; Declare the string constant as a global constant.</i>&nbsp;
495<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>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497<i>; External declaration of the puts function</i>&nbsp;
498<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>&nbsp;
502 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
503 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
506 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
507 <a href="#i_ret">ret</a> i32 0&nbsp;
508}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]509
510<i>; Named metadata</i>
511!1 = metadata !{i32 41}
512!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]513</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]515<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]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]526
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]538
539<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]541 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
542 by objects in the current module. In particular, linking code into a
543 module with an private global value may cause the private to be renamed as
544 necessary to avoid collisions. Because the symbol is private to the
545 module, all references can be updated. This doesn't show up in any symbol
546 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]549 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
550 assembler and evaluated by the linker. Unlike normal strong symbols, they
551 are removed by the linker from the final linked image (executable or
552 dynamic library).</dd>
553
554 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
555 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
556 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
557 linker. The symbols are removed by the linker from the final linked image
558 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]559
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]561 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]562 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
563 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]564
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]565 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]566 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]567 into the object file corresponding to the LLVM module. They exist to
568 allow inlining and other optimizations to take place given knowledge of
569 the definition of the global, which is known to be somewhere outside the
570 module. Globals with <tt>available_externally</tt> linkage are allowed to
571 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
572 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]573
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]575 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]576 the same name when linkage occurs. This can be used to implement
577 some forms of inline functions, templates, or other code which must be
578 generated in each translation unit that uses it, but where the body may
579 be overridden with a more definitive definition later. Unreferenced
580 <tt>linkonce</tt> globals are allowed to be discarded. Note that
581 <tt>linkonce</tt> linkage does not actually allow the optimizer to
582 inline the body of this function into callers because it doesn't know if
583 this definition of the function is the definitive definition within the
584 program or whether it will be overridden by a stronger definition.
585 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
586 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]587
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]588 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]589 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
590 <tt>linkonce</tt> linkage, except that unreferenced globals with
591 <tt>weak</tt> linkage may not be discarded. This is used for globals that
592 are declared "weak" in C source code.</dd>
593
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]595 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
596 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
597 global scope.
598 Symbols with "<tt>common</tt>" linkage are merged in the same way as
599 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]600 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]601 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]602 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
603 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]605
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]607 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]608 pointer to array type. When two global variables with appending linkage
609 are linked together, the two global arrays are appended together. This is
610 the LLVM, typesafe, equivalent of having the system linker append together
611 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]612
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]614 <dd>The semantics of this linkage follow the ELF object file model: the symbol
615 is weak until linked, if not linked, the symbol becomes null instead of
616 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]617
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
619 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 <dd>Some languages allow differing globals to be merged, such as two functions
621 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]622 that only equivalent globals are ever merged (the "one definition rule"
623 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 and <tt>weak_odr</tt> linkage types to indicate that the global will only
625 be merged with equivalent globals. These linkage types are otherwise the
626 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]627
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]629 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 visible, meaning that it participates in linkage and can be used to
631 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]632</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]633
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634<p>The next two types of linkage are targeted for Microsoft Windows platform
635 only. They are designed to support importing (exporting) symbols from (to)
636 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]638<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]639 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]640 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]641 or variable via a global pointer to a pointer that is set up by the DLL
642 exporting the symbol. On Microsoft Windows targets, the pointer name is
643 formed by combining <code>__imp_</code> and the function or variable
644 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]645
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]646 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648 pointer to a pointer in a DLL, so that it can be referenced with the
649 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
650 name is formed by combining <code>__imp_</code> and the function or
651 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]652</dl>
653
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]654<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
655 another module defined a "<tt>.LC0</tt>" variable and was linked with this
656 one, one of the two would be renamed, preventing a collision. Since
657 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
658 declarations), they are accessible outside of the current module.</p>
659
660<p>It is illegal for a function <i>declaration</i> to have any linkage type
661 other than "externally visible", <tt>dllimport</tt>
662 or <tt>extern_weak</tt>.</p>
663
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]664<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]665 or <tt>weak_odr</tt> linkages.</p>
666
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]667</div>
668
669<!-- ======================================================================= -->
670<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]671 <a name="callingconv">Calling Conventions</a>
672</div>
673
674<div class="doc_text">
675
676<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]677 and <a href="#i_invoke">invokes</a> can all have an optional calling
678 convention specified for the call. The calling convention of any pair of
679 dynamic caller/callee must match, or the behavior of the program is
680 undefined. The following calling conventions are supported by LLVM, and more
681 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682
683<dl>
684 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]686 specified) matches the target C calling conventions. This calling
687 convention supports varargs function calls and tolerates some mismatch in
688 the declared prototype and implemented declaration of the function (as
689 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690
691 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]693 (e.g. by passing things in registers). This calling convention allows the
694 target to use whatever tricks it wants to produce fast code for the
695 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]696 (Application Binary Interface).
697 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]698 when this or the GHC convention is used.</a> This calling convention
699 does not support varargs and requires the prototype of all callees to
700 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701
702 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]703 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]704 as possible under the assumption that the call is not commonly executed.
705 As such, these calls often preserve all registers so that the call does
706 not break any live ranges in the caller side. This calling convention
707 does not support varargs and requires the prototype of all callees to
708 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]709
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]710 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
711 <dd>This calling convention has been implemented specifically for use by the
712 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
713 It passes everything in registers, going to extremes to achieve this by
714 disabling callee save registers. This calling convention should not be
715 used lightly but only for specific situations such as an alternative to
716 the <em>register pinning</em> performance technique often used when
717 implementing functional programming languages.At the moment only X86
718 supports this convention and it has the following limitations:
719 <ul>
720 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
721 floating point types are supported.</li>
722 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
723 6 floating point parameters.</li>
724 </ul>
725 This calling convention supports
726 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
727 requires both the caller and callee are using it.
728 </dd>
729
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]730 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]731 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]732 target-specific calling conventions to be used. Target specific calling
733 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]734</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]735
736<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]737 support Pascal conventions or any other well-known target-independent
738 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]739
740</div>
741
742<!-- ======================================================================= -->
743<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]744 <a name="visibility">Visibility Styles</a>
745</div>
746
747<div class="doc_text">
748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749<p>All Global Variables and Functions have one of the following visibility
750 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]751
752<dl>
753 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]754 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]755 that the declaration is visible to other modules and, in shared libraries,
756 means that the declared entity may be overridden. On Darwin, default
757 visibility means that the declaration is visible to other modules. Default
758 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]759
760 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]762 object if they are in the same shared object. Usually, hidden visibility
763 indicates that the symbol will not be placed into the dynamic symbol
764 table, so no other module (executable or shared library) can reference it
765 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]766
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]767 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]768 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]769 the dynamic symbol table, but that references within the defining module
770 will bind to the local symbol. That is, the symbol cannot be overridden by
771 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]772</dl>
773
774</div>
775
776<!-- ======================================================================= -->
777<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]778 <a name="namedtypes">Named Types</a>
779</div>
780
781<div class="doc_text">
782
783<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]784 it easier to read the IR and make the IR more condensed (particularly when
785 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]786
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]787<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788%mytype = type { %mytype*, i32 }
789</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]791<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]792 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]793 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]794
795<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]796 and that you can therefore specify multiple names for the same type. This
797 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
798 uses structural typing, the name is not part of the type. When printing out
799 LLVM IR, the printer will pick <em>one name</em> to render all types of a
800 particular shape. This means that if you have code where two different
801 source types end up having the same LLVM type, that the dumper will sometimes
802 print the "wrong" or unexpected type. This is an important design point and
803 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805</div>
806
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]807<!-- ======================================================================= -->
808<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]809 <a name="globalvars">Global Variables</a>
810</div>
811
812<div class="doc_text">
813
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]814<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815 instead of run-time. Global variables may optionally be initialized, may
816 have an explicit section to be placed in, and may have an optional explicit
817 alignment specified. A variable may be defined as "thread_local", which
818 means that it will not be shared by threads (each thread will have a
819 separated copy of the variable). A variable may be defined as a global
820 "constant," which indicates that the contents of the variable
821 will <b>never</b> be modified (enabling better optimization, allowing the
822 global data to be placed in the read-only section of an executable, etc).
823 Note that variables that need runtime initialization cannot be marked
824 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
827 constant, even if the final definition of the global is not. This capability
828 can be used to enable slightly better optimization of the program, but
829 requires the language definition to guarantee that optimizations based on the
830 'constantness' are valid for the translation units that do not include the
831 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]832
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]833<p>As SSA values, global variables define pointer values that are in scope
834 (i.e. they dominate) all basic blocks in the program. Global variables
835 always define a pointer to their "content" type because they describe a
836 region of memory, and all memory objects in LLVM are accessed through
837 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]839<p>A global variable may be declared to reside in a target-specific numbered
840 address space. For targets that support them, address spaces may affect how
841 optimizations are performed and/or what target instructions are used to
842 access the variable. The default address space is zero. The address space
843 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]844
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]845<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]846 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]847
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]848<p>An explicit alignment may be specified for a global, which must be a power
849 of 2. If not present, or if the alignment is set to zero, the alignment of
850 the global is set by the target to whatever it feels convenient. If an
851 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]852 alignment. Targets and optimizers are not allowed to over-align the global
853 if the global has an assigned section. In this case, the extra alignment
854 could be observable: for example, code could assume that the globals are
855 densely packed in their section and try to iterate over them as an array,
856 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]857
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858<p>For example, the following defines a global in a numbered address space with
859 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]860
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]861<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]862@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]863</pre>
864
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]865</div>
866
867
868<!-- ======================================================================= -->
869<div class="doc_subsection">
870 <a name="functionstructure">Functions</a>
871</div>
872
873<div class="doc_text">
874
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]875<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]876 optional <a href="#linkage">linkage type</a>, an optional
877 <a href="#visibility">visibility style</a>, an optional
878 <a href="#callingconv">calling convention</a>, a return type, an optional
879 <a href="#paramattrs">parameter attribute</a> for the return type, a function
880 name, a (possibly empty) argument list (each with optional
881 <a href="#paramattrs">parameter attributes</a>), optional
882 <a href="#fnattrs">function attributes</a>, an optional section, an optional
883 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
884 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]885
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]886<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
887 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]888 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]889 <a href="#callingconv">calling convention</a>, a return type, an optional
890 <a href="#paramattrs">parameter attribute</a> for the return type, a function
891 name, a possibly empty list of arguments, an optional alignment, and an
892 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]893
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]894<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]895 (Control Flow Graph) for the function. Each basic block may optionally start
896 with a label (giving the basic block a symbol table entry), contains a list
897 of instructions, and ends with a <a href="#terminators">terminator</a>
898 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]899
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]900<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]901 executed on entrance to the function, and it is not allowed to have
902 predecessor basic blocks (i.e. there can not be any branches to the entry
903 block of a function). Because the block can have no predecessors, it also
904 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]905
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]906<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]907 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]908
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]909<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]910 the alignment is set to zero, the alignment of the function is set by the
911 target to whatever it feels convenient. If an explicit alignment is
912 specified, the function is forced to have at least that much alignment. All
913 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]914
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]915<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]916<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]917define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]918 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
919 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
920 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
921 [<a href="#gc">gc</a>] { ... }
922</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]923
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924</div>
925
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]926<!-- ======================================================================= -->
927<div class="doc_subsection">
928 <a name="aliasstructure">Aliases</a>
929</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]930
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]931<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932
933<p>Aliases act as "second name" for the aliasee value (which can be either
934 function, global variable, another alias or bitcast of global value). Aliases
935 may have an optional <a href="#linkage">linkage type</a>, and an
936 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]937
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]938<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]939<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]940@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]941</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]942
943</div>
944
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]945<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]946<div class="doc_subsection">
947 <a name="namedmetadatastructure">Named Metadata</a>
948</div>
949
950<div class="doc_text">
951
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]952<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]953 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]954 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]955
956<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]957<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]958; Some unnamed metadata nodes, which are referenced by the named metadata.
959!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]960!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]961!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]962; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]963!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]964</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]965
966</div>
967
968<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]969<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]970
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971<div class="doc_text">
972
973<p>The return type and each parameter of a function type may have a set of
974 <i>parameter attributes</i> associated with them. Parameter attributes are
975 used to communicate additional information about the result or parameters of
976 a function. Parameter attributes are considered to be part of the function,
977 not of the function type, so functions with different parameter attributes
978 can have the same function type.</p>
979
980<p>Parameter attributes are simple keywords that follow the type specified. If
981 multiple parameter attributes are needed, they are space separated. For
982 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]983
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]984<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]985declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]986declare i32 @atoi(i8 zeroext)
987declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]988</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]989
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]990<p>Note that any attributes for the function result (<tt>nounwind</tt>,
991 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]993<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]994
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]995<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]996 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]997 <dd>This indicates to the code generator that the parameter or return value
998 should be zero-extended to a 32-bit value by the caller (for a parameter)
999 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1000
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1001 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1002 <dd>This indicates to the code generator that the parameter or return value
1003 should be sign-extended to a 32-bit value by the caller (for a parameter)
1004 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1005
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates that this parameter or return value should be treated in a
1008 special target-dependent fashion during while emitting code for a function
1009 call or return (usually, by putting it in a register as opposed to memory,
1010 though some targets use it to distinguish between two different kinds of
1011 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates that the pointer parameter should really be passed by value
1015 to the function. The attribute implies that a hidden copy of the pointee
1016 is made between the caller and the callee, so the callee is unable to
1017 modify the value in the callee. This attribute is only valid on LLVM
1018 pointer arguments. It is generally used to pass structs and arrays by
1019 value, but is also valid on pointers to scalars. The copy is considered
1020 to belong to the caller not the callee (for example,
1021 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1022 <tt>byval</tt> parameters). This is not a valid attribute for return
1023 values. The byval attribute also supports specifying an alignment with
1024 the align attribute. This has a target-specific effect on the code
1025 generator that usually indicates a desired alignment for the synthesized
1026 stack slot.</dd>
1027
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1028 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates that the pointer parameter specifies the address of a
1030 structure that is the return value of the function in the source program.
1031 This pointer must be guaranteed by the caller to be valid: loads and
1032 stores to the structure may be assumed by the callee to not to trap. This
1033 may only be applied to the first parameter. This is not a valid attribute
1034 for return values. </dd>
1035
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1036 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1037 <dd>This indicates that pointer values
1038 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1039 value do not alias pointer values which are not <i>based</i> on it,
1040 ignoring certain "irrelevant" dependencies.
1041 For a call to the parent function, dependencies between memory
1042 references from before or after the call and from those during the call
1043 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1044 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1045 The caller shares the responsibility with the callee for ensuring that
1046 these requirements are met.
1047 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1048 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1049<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1050 Note that this definition of <tt>noalias</tt> is intentionally
1051 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1052 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1053<br>
1054 For function return values, C99's <tt>restrict</tt> is not meaningful,
1055 while LLVM's <tt>noalias</tt> is.
1056 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1057
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1058 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1063 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1081<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1082define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1083</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1084
1085<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1086 collector which will cause the compiler to alter its output in order to
1087 support the named garbage collection algorithm.</p>
1088
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1089</div>
1090
1091<!-- ======================================================================= -->
1092<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1093 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1094</div>
1095
1096<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1097
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1098<p>Function attributes are set to communicate additional information about a
1099 function. Function attributes are considered to be part of the function, not
1100 of the function type, so functions with different parameter attributes can
1101 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1102
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1103<p>Function attributes are simple keywords that follow the type specified. If
1104 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1105
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1106<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107define void @f() noinline { ... }
1108define void @f() alwaysinline { ... }
1109define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1110define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1111</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1112
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1113<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1114 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1115 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1116 the backend should forcibly align the stack pointer. Specify the
1117 desired alignment, which must be a power of two, in parentheses.
1118
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1119 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120 <dd>This attribute indicates that the inliner should attempt to inline this
1121 function into callers whenever possible, ignoring any active inlining size
1122 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1124 <dt><tt><b>inlinehint</b></tt></dt>
1125 <dd>This attribute indicates that the source code contained a hint that inlining
1126 this function is desirable (such as the "inline" keyword in C/C++). It
1127 is just a hint; it imposes no requirements on the inliner.</dd>
1128
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1129 <dt><tt><b>naked</b></tt></dt>
1130 <dd>This attribute disables prologue / epilogue emission for the function.
1131 This can have very system-specific consequences.</dd>
1132
1133 <dt><tt><b>noimplicitfloat</b></tt></dt>
1134 <dd>This attributes disables implicit floating point instructions.</dd>
1135
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1136 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1137 <dd>This attribute indicates that the inliner should never inline this
1138 function in any situation. This attribute may not be used together with
1139 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1140
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1141 <dt><tt><b>noredzone</b></tt></dt>
1142 <dd>This attribute indicates that the code generator should not use a red
1143 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1144
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1145 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1146 <dd>This function attribute indicates that the function never returns
1147 normally. This produces undefined behavior at runtime if the function
1148 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1149
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1150 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1151 <dd>This function attribute indicates that the function never returns with an
1152 unwind or exceptional control flow. If the function does unwind, its
1153 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1154
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1155 <dt><tt><b>optsize</b></tt></dt>
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>
1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This attribute indicates that the function computes its result (or decides
1162 to unwind an exception) based strictly on its arguments, without
1163 dereferencing any pointer arguments or otherwise accessing any mutable
1164 state (e.g. memory, control registers, etc) visible to caller functions.
1165 It does not write through any pointer arguments
1166 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1167 changes any state visible to callers. This means that it cannot unwind
1168 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1169 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1170
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the function does not write through any
1173 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1174 arguments) or otherwise modify any state (e.g. memory, control registers,
1175 etc) visible to caller functions. It may dereference pointer arguments
1176 and read state that may be set in the caller. A readonly function always
1177 returns the same value (or unwinds an exception identically) when called
1178 with the same set of arguments and global state. It cannot unwind an
1179 exception by calling the <tt>C++</tt> exception throwing methods, but may
1180 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This attribute indicates that the function should emit a stack smashing
1184 protector. It is in the form of a "canary"&mdash;a random value placed on
1185 the stack before the local variables that's checked upon return from the
1186 function to see if it has been overwritten. A heuristic is used to
1187 determine if a function needs stack protectors or not.<br>
1188<br>
1189 If a function that has an <tt>ssp</tt> attribute is inlined into a
1190 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1191 function will have an <tt>ssp</tt> attribute.</dd>
1192
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1193 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1194 <dd>This attribute indicates that the function should <em>always</em> emit a
1195 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1196 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1197<br>
1198 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1199 function that doesn't have an <tt>sspreq</tt> attribute or which has
1200 an <tt>ssp</tt> attribute, then the resulting function will have
1201 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1202</dl>
1203
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1208 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1209</div>
1210
1211<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212
1213<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1214 the GCC "file scope inline asm" blocks. These blocks are internally
1215 concatenated by LLVM and treated as a single unit, but may be separated in
1216 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1217
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1218<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1219module asm "inline asm code goes here"
1220module asm "more can go here"
1221</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1222
1223<p>The strings can contain any character by escaping non-printable characters.
1224 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]1225 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1227<p>The inline asm code is simply printed to the machine code .s file when
1228 assembly code is generated.</p>
1229
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1230</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1231
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1232<!-- ======================================================================= -->
1233<div class="doc_subsection">
1234 <a name="datalayout">Data Layout</a>
1235</div>
1236
1237<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1238
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1239<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1240 data is to be laid out in memory. The syntax for the data layout is
1241 simply:</p>
1242
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1243<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244target datalayout = "<i>layout specification</i>"
1245</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1246
1247<p>The <i>layout specification</i> consists of a list of specifications
1248 separated by the minus sign character ('-'). Each specification starts with
1249 a letter and may include other information after the letter to define some
1250 aspect of the data layout. The specifications accepted are as follows:</p>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252<dl>
1253 <dt><tt>E</tt></dt>
1254 <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]1255 bits with the most significance have the lowest address location.</dd>
1256
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1257 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1258 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1259 the bits with the least significance have the lowest address
1260 location.</dd>
1261
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1262 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1263 <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]1264 <i>preferred</i> alignments. All sizes are in bits. Specifying
1265 the <i>pref</i> alignment is optional. If omitted, the
1266 preceding <tt>:</tt> should be omitted too.</dd>
1267
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1268 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1269 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1270 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1271
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1273 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 <i>size</i>.</dd>
1275
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1277 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1278 <i>size</i>. Only values of <i>size</i> that are supported by the target
1279 will work. 32 (float) and 64 (double) are supported on all targets;
1280 80 or 128 (different flavors of long double) are also supported on some
1281 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1283 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1284 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1285 <i>size</i>.</dd>
1286
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1287 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1288 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1289 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1290
1291 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1292 <dd>This specifies a set of native integer widths for the target CPU
1293 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1294 "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]1295 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1296 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1297</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1298
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1299<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1300 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1301 specifications in the <tt>datalayout</tt> keyword. The default specifications
1302 are given in this list:</p>
1303
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1304<ul>
1305 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1306 <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]1307 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1308 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1309 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1310 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1311 <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]1312 alignment of 64-bits</li>
1313 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1314 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1315 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1316 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1317 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1318 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1320
1321<p>When LLVM is determining the alignment for a given type, it uses the
1322 following rules:</p>
1323
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1324<ol>
1325 <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]1326 specification is used.</li>
1327
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1328 <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]1329 smallest integer type that is larger than the bitwidth of the sought type
1330 is used. If none of the specifications are larger than the bitwidth then
1331 the the largest integer type is used. For example, given the default
1332 specifications above, the i7 type will use the alignment of i8 (next
1333 largest) while both i65 and i256 will use the alignment of i64 (largest
1334 specified).</li>
1335
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1336 <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]1337 largest vector type that is smaller than the sought vector type will be
1338 used as a fall back. This happens because &lt;128 x double&gt; can be
1339 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1343
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1344<!-- ======================================================================= -->
1345<div class="doc_subsection">
1346 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1347</div>
1348
1349<div class="doc_text">
1350
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1351<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1352with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1353is undefined. Pointer values are associated with address ranges
1354according to the following rules:</p>
1355
1356<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1357 <li>A pointer value is associated with the addresses associated with
1358 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1359 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1360 range of the variable's storage.</li>
1361 <li>The result value of an allocation instruction is associated with
1362 the address range of the allocated storage.</li>
1363 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1364 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1365 <li>An integer constant other than zero or a pointer value returned
1366 from a function not defined within LLVM may be associated with address
1367 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1368 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1369 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1370</ul>
1371
1372<p>A pointer value is <i>based</i> on another pointer value according
1373 to the following rules:</p>
1374
1375<ul>
1376 <li>A pointer value formed from a
1377 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1378 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1379 <li>The result value of a
1380 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1381 of the <tt>bitcast</tt>.</li>
1382 <li>A pointer value formed by an
1383 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1384 pointer values that contribute (directly or indirectly) to the
1385 computation of the pointer's value.</li>
1386 <li>The "<i>based</i> on" relationship is transitive.</li>
1387</ul>
1388
1389<p>Note that this definition of <i>"based"</i> is intentionally
1390 similar to the definition of <i>"based"</i> in C99, though it is
1391 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1392
1393<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1394<tt><a href="#i_load">load</a></tt> merely indicates the size and
1395alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1396interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1397<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1398and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1399
1400<p>Consequently, type-based alias analysis, aka TBAA, aka
1401<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1402LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1403additional information which specialized optimization passes may use
1404to implement type-based alias analysis.</p>
1405
1406</div>
1407
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1408<!-- ======================================================================= -->
1409<div class="doc_subsection">
1410 <a name="volatile">Volatile Memory Accesses</a>
1411</div>
1412
1413<div class="doc_text">
1414
1415<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1416href="#i_store"><tt>store</tt></a>s, and <a
1417href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1418The optimizers must not change the number of volatile operations or change their
1419order of execution relative to other volatile operations. The optimizers
1420<i>may</i> change the order of volatile operations relative to non-volatile
1421operations. This is not Java's "volatile" and has no cross-thread
1422synchronization behavior.</p>
1423
1424</div>
1425
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1426<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1427<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1428<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1430<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1431
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1432<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1433 intermediate representation. Being typed enables a number of optimizations
1434 to be performed on the intermediate representation directly, without having
1435 to do extra analyses on the side before the transformation. A strong type
1436 system makes it easier to read the generated code and enables novel analyses
1437 and transformations that are not feasible to perform on normal three address
1438 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1439
1440</div>
1441
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1442<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1443<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1444Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1446<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1447
1448<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1449
1450<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1451 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1452 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1453 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1454 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1455 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1456 </tr>
1457 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1458 <td><a href="#t_floating">floating point</a></td>
1459 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1460 </tr>
1461 <tr>
1462 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1463 <td><a href="#t_integer">integer</a>,
1464 <a href="#t_floating">floating point</a>,
1465 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1466 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1467 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1468 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1469 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1470 <a href="#t_label">label</a>,
1471 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1472 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1473 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474 <tr>
1475 <td><a href="#t_primitive">primitive</a></td>
1476 <td><a href="#t_label">label</a>,
1477 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1478 <a href="#t_floating">floating point</a>,
1479 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1480 </tr>
1481 <tr>
1482 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1483 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484 <a href="#t_function">function</a>,
1485 <a href="#t_pointer">pointer</a>,
1486 <a href="#t_struct">structure</a>,
1487 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1488 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1489 <a href="#t_vector">vector</a>,
1490 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1491 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1493 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1494</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1495
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1496<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1497 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1498 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1500</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1501
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1502<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1503<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1504
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1505<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1506
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1507<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1508 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1510</div>
1511
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1512<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1513<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1514
1515<div class="doc_text">
1516
1517<h5>Overview:</h5>
1518<p>The integer type is a very simple type that simply specifies an arbitrary
1519 bit width for the integer type desired. Any bit width from 1 bit to
1520 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1521
1522<h5>Syntax:</h5>
1523<pre>
1524 iN
1525</pre>
1526
1527<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1528 value.</p>
1529
1530<h5>Examples:</h5>
1531<table class="layout">
1532 <tr class="layout">
1533 <td class="left"><tt>i1</tt></td>
1534 <td class="left">a single-bit integer.</td>
1535 </tr>
1536 <tr class="layout">
1537 <td class="left"><tt>i32</tt></td>
1538 <td class="left">a 32-bit integer.</td>
1539 </tr>
1540 <tr class="layout">
1541 <td class="left"><tt>i1942652</tt></td>
1542 <td class="left">a really big integer of over 1 million bits.</td>
1543 </tr>
1544</table>
1545
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1546</div>
1547
1548<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1549<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1550
1551<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1552
1553<table>
1554 <tbody>
1555 <tr><th>Type</th><th>Description</th></tr>
1556 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1557 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1558 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1559 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1560 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1561 </tbody>
1562</table>
1563
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1564</div>
1565
1566<!-- _______________________________________________________________________ -->
1567<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1568
1569<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1570
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1571<h5>Overview:</h5>
1572<p>The void type does not represent any value and has no size.</p>
1573
1574<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1575<pre>
1576 void
1577</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1578
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1579</div>
1580
1581<!-- _______________________________________________________________________ -->
1582<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1583
1584<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1585
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1586<h5>Overview:</h5>
1587<p>The label type represents code labels.</p>
1588
1589<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1590<pre>
1591 label
1592</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1593
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1594</div>
1595
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1596<!-- _______________________________________________________________________ -->
1597<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1598
1599<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1600
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1601<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1602<p>The metadata type represents embedded metadata. No derived types may be
1603 created from metadata except for <a href="#t_function">function</a>
1604 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1605
1606<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1607<pre>
1608 metadata
1609</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1611</div>
1612
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1613
1614<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1615<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1616
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1617<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1618
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1619<p>The real power in LLVM comes from the derived types in the system. This is
1620 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1621 useful types. Each of these types contain one or more element types which
1622 may be a primitive type, or another derived type. For example, it is
1623 possible to have a two dimensional array, using an array as the element type
1624 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1625
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1626
1627</div>
1628
1629<!-- _______________________________________________________________________ -->
1630<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1631
1632<div class="doc_text">
1633
1634<p>Aggregate Types are a subset of derived types that can contain multiple
1635 member types. <a href="#t_array">Arrays</a>,
1636 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1637 <a href="#t_union">unions</a> are aggregate types.</p>
1638
1639</div>
1640
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1641<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1642<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1644<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1646<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1648 sequentially in memory. The array type requires a size (number of elements)
1649 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1651<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1652<pre>
1653 [&lt;# elements&gt; x &lt;elementtype&gt;]
1654</pre>
1655
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1656<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1657 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1658
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1659<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1660<table class="layout">
1661 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1662 <td class="left"><tt>[40 x i32]</tt></td>
1663 <td class="left">Array of 40 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[41 x i32]</tt></td>
1667 <td class="left">Array of 41 32-bit integer values.</td>
1668 </tr>
1669 <tr class="layout">
1670 <td class="left"><tt>[4 x i8]</tt></td>
1671 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1672 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1673</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1674<p>Here are some examples of multidimensional arrays:</p>
1675<table class="layout">
1676 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1677 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1678 <td class="left">3x4 array of 32-bit integer values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1682 <td class="left">12x10 array of single precision floating point values.</td>
1683 </tr>
1684 <tr class="layout">
1685 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1686 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1687 </tr>
1688</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1689
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1690<p>There is no restriction on indexing beyond the end of the array implied by
1691 a static type (though there are restrictions on indexing beyond the bounds
1692 of an allocated object in some cases). This means that single-dimension
1693 'variable sized array' addressing can be implemented in LLVM with a zero
1694 length array type. An implementation of 'pascal style arrays' in LLVM could
1695 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1697</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1698
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1701
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1702<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1703
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1705<p>The function type can be thought of as a function signature. It consists of
1706 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]1707 function type is a scalar type, a void type, a struct type, or a union
1708 type. If the return type is a struct type then all struct elements must be
1709 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1710
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1712<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1713 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1714</pre>
1715
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1716<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]1717 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1718 which indicates that the function takes a variable number of arguments.
1719 Variable argument functions can access their arguments with
1720 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1721 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1722 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725<table class="layout">
1726 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1727 <td class="left"><tt>i32 (i32)</tt></td>
1728 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1729 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1730 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1731 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1732 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1733 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1734 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1735 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1736 </td>
1737 </tr><tr class="layout">
1738 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1739 <td class="left">A vararg function that takes at least one
1740 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1741 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1742 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1743 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1744 </tr><tr class="layout">
1745 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1746 <td class="left">A function taking an <tt>i32</tt>, returning a
1747 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1748 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760<p>The structure type is used to represent a collection of data members together
1761 in memory. The packing of the field types is defined to match the ABI of the
1762 underlying processor. The elements of a structure may be any type that has a
1763 size.</p>
1764
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1765<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1766 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1767 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1768 Structures in registers are accessed using the
1769 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1770 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1772<pre>
1773 { &lt;type list&gt; }
1774</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1775
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1776<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1779 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1780 <td class="left">A triple of three <tt>i32</tt> values</td>
1781 </tr><tr class="layout">
1782 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1783 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1784 second element is a <a href="#t_pointer">pointer</a> to a
1785 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1786 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1789
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1790</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1792<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1793<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1794</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1795
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1796<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1797
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1798<h5>Overview:</h5>
1799<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1800 together in memory. There is no padding between fields. Further, the
1801 alignment of a packed structure is 1 byte. The elements of a packed
1802 structure may be any type that has a size.</p>
1803
1804<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1805 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1806 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1807
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1808<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1809<pre>
1810 &lt; { &lt;type list&gt; } &gt;
1811</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1812
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1813<h5>Examples:</h5>
1814<table class="layout">
1815 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1816 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1817 <td class="left">A triple of three <tt>i32</tt> values</td>
1818 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1819 <td class="left">
1820<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1821 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1822 second element is a <a href="#t_pointer">pointer</a> to a
1823 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1824 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1825 </tr>
1826</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1828</div>
1829
1830<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1831<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1832
1833<div class="doc_text">
1834
1835<h5>Overview:</h5>
1836<p>A union type describes an object with size and alignment suitable for
1837 an object of any one of a given set of types (also known as an "untagged"
1838 union). It is similar in concept and usage to a
1839 <a href="#t_struct">struct</a>, except that all members of the union
1840 have an offset of zero. The elements of a union may be any type that has a
1841 size. Unions must have at least one member - empty unions are not allowed.
1842 </p>
1843
1844<p>The size of the union as a whole will be the size of its largest member,
1845 and the alignment requirements of the union as a whole will be the largest
1846 alignment requirement of any member.</p>
1847
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1848<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]1849 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1850 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1851 Since all members are at offset zero, the getelementptr instruction does
1852 not affect the address, only the type of the resulting pointer.</p>
1853
1854<h5>Syntax:</h5>
1855<pre>
1856 union { &lt;type list&gt; }
1857</pre>
1858
1859<h5>Examples:</h5>
1860<table class="layout">
1861 <tr class="layout">
1862 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1863 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1864 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1865 </tr><tr class="layout">
1866 <td class="left">
1867 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1868 <td class="left">A union, where the first element is a <tt>float</tt> and the
1869 second element is a <a href="#t_pointer">pointer</a> to a
1870 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1871 an <tt>i32</tt>.</td>
1872 </tr>
1873</table>
1874
1875</div>
1876
1877<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880<div class="doc_text">
1881
1882<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1883<p>The pointer type is used to specify memory locations.
1884 Pointers are commonly used to reference objects in memory.</p>
1885
1886<p>Pointer types may have an optional address space attribute defining the
1887 numbered address space where the pointed-to object resides. The default
1888 address space is number zero. The semantics of non-zero address
1889 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1890
1891<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1892 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1893
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1894<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1895<pre>
1896 &lt;type&gt; *
1897</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1898
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1899<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1900<table class="layout">
1901 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1902 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1903 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1904 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1905 </tr>
1906 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1907 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1908 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1909 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1910 <tt>i32</tt>.</td>
1911 </tr>
1912 <tr class="layout">
1913 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1914 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1915 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1916 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1917</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1920
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1922<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1924<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1925
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1926<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927<p>A vector type is a simple derived type that represents a vector of elements.
1928 Vector types are used when multiple primitive data are operated in parallel
1929 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1930 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1931 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1932
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1933<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1934<pre>
1935 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1936</pre>
1937
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1938<p>The number of elements is a constant integer value; elementtype may be any
1939 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1940
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1941<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1942<table class="layout">
1943 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1944 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1945 <td class="left">Vector of 4 32-bit integer values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1949 <td class="left">Vector of 8 32-bit floating-point values.</td>
1950 </tr>
1951 <tr class="layout">
1952 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1953 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1954 </tr>
1955</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1957</div>
1958
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1959<!-- _______________________________________________________________________ -->
1960<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1961<div class="doc_text">
1962
1963<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1964<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1965 corresponds (for example) to the C notion of a forward declared structure
1966 type. In LLVM, opaque types can eventually be resolved to any type (not just
1967 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1968
1969<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1970<pre>
1971 opaque
1972</pre>
1973
1974<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1975<table class="layout">
1976 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1977 <td class="left"><tt>opaque</tt></td>
1978 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1979 </tr>
1980</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1981
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1982</div>
1983
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1984<!-- ======================================================================= -->
1985<div class="doc_subsection">
1986 <a name="t_uprefs">Type Up-references</a>
1987</div>
1988
1989<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1990
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1991<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1992<p>An "up reference" allows you to refer to a lexically enclosing type without
1993 requiring it to have a name. For instance, a structure declaration may
1994 contain a pointer to any of the types it is lexically a member of. Example
1995 of up references (with their equivalent as named type declarations)
1996 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1997
1998<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1999 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000 { \2 }* %y = type { %y }*
2001 \1* %z = type %z*
2002</pre>
2003
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2004<p>An up reference is needed by the asmprinter for printing out cyclic types
2005 when there is no declared name for a type in the cycle. Because the
2006 asmprinter does not want to print out an infinite type string, it needs a
2007 syntax to handle recursive types that have no names (all names are optional
2008 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2009
2010<h5>Syntax:</h5>
2011<pre>
2012 \&lt;level&gt;
2013</pre>
2014
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2015<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]2016
2017<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2018<table class="layout">
2019 <tr class="layout">
2020 <td class="left"><tt>\1*</tt></td>
2021 <td class="left">Self-referential pointer.</td>
2022 </tr>
2023 <tr class="layout">
2024 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2025 <td class="left">Recursive structure where the upref refers to the out-most
2026 structure.</td>
2027 </tr>
2028</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2030</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2031
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2032<!-- *********************************************************************** -->
2033<div class="doc_section"> <a name="constants">Constants</a> </div>
2034<!-- *********************************************************************** -->
2035
2036<div class="doc_text">
2037
2038<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2039 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2040
2041</div>
2042
2043<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2044<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2045
2046<div class="doc_text">
2047
2048<dl>
2049 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2050 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2051 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2052
2053 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2054 <dd>Standard integers (such as '4') are constants of
2055 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2056 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2057
2058 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2059 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2060 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2061 notation (see below). The assembler requires the exact decimal value of a
2062 floating-point constant. For example, the assembler accepts 1.25 but
2063 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2064 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2065
2066 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2067 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2068 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2069</dl>
2070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071<p>The one non-intuitive notation for constants is the hexadecimal form of
2072 floating point constants. For example, the form '<tt>double
2073 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2074 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2075 constants are required (and the only time that they are generated by the
2076 disassembler) is when a floating point constant must be emitted but it cannot
2077 be represented as a decimal floating point number in a reasonable number of
2078 digits. For example, NaN's, infinities, and other special values are
2079 represented in their IEEE hexadecimal format so that assembly and disassembly
2080 do not cause any bits to change in the constants.</p>
2081
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2082<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2083 represented using the 16-digit form shown above (which matches the IEEE754
2084 representation for double); float values must, however, be exactly
2085 representable as IEE754 single precision. Hexadecimal format is always used
2086 for long double, and there are three forms of long double. The 80-bit format
2087 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2088 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2089 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2090 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2091 currently supported target uses this format. Long doubles will only work if
2092 they match the long double format on your target. All hexadecimal formats
2093 are big-endian (sign bit at the left).</p>
2094
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2095</div>
2096
2097<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2098<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2099<a name="aggregateconstants"></a> <!-- old anchor -->
2100<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2101</div>
2102
2103<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2104
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2105<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2106 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2107
2108<dl>
2109 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2110 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2111 type definitions (a comma separated list of elements, surrounded by braces
2112 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2113 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2114 Structure constants must have <a href="#t_struct">structure type</a>, and
2115 the number and types of elements must match those specified by the
2116 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2117
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2118 <dt><b>Union constants</b></dt>
2119 <dd>Union constants are represented with notation similar to a structure with
2120 a single element - that is, a single typed element surrounded
2121 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2122 <a href="#t_union">union type</a> can be initialized with a single-element
2123 struct as long as the type of the struct element matches the type of
2124 one of the union members.</dd>
2125
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2126 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2127 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2128 definitions (a comma separated list of elements, surrounded by square
2129 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2130 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2131 the number and types of elements must match those specified by the
2132 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2133
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2134 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2135 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2136 definitions (a comma separated list of elements, surrounded by
2137 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2138 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2139 have <a href="#t_vector">vector type</a>, and the number and types of
2140 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2141
2142 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2143 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2144 value to zero of <em>any</em> type, including scalar and
2145 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2146 This is often used to avoid having to print large zero initializers
2147 (e.g. for large arrays) and is always exactly equivalent to using explicit
2148 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2149
2150 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2151 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2152 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2153 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2154 be interpreted as part of the instruction stream, metadata is a place to
2155 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2156</dl>
2157
2158</div>
2159
2160<!-- ======================================================================= -->
2161<div class="doc_subsection">
2162 <a name="globalconstants">Global Variable and Function Addresses</a>
2163</div>
2164
2165<div class="doc_text">
2166
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167<p>The addresses of <a href="#globalvars">global variables</a>
2168 and <a href="#functionstructure">functions</a> are always implicitly valid
2169 (link-time) constants. These constants are explicitly referenced when
2170 the <a href="#identifiers">identifier for the global</a> is used and always
2171 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2172 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2173
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2174<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2175@X = global i32 17
2176@Y = global i32 42
2177@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2178</pre>
2179
2180</div>
2181
2182<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2183<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2184<div class="doc_text">
2185
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186<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]2187 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 Undefined values may be of any type (other than label or void) and be used
2189 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2190
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2191<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2192 program is well defined no matter what value is used. This gives the
2193 compiler more freedom to optimize. Here are some examples of (potentially
2194 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2196
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2197<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2198 %A = add %X, undef
2199 %B = sub %X, undef
2200 %C = xor %X, undef
2201Safe:
2202 %A = undef
2203 %B = undef
2204 %C = undef
2205</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2210<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2211 %A = or %X, undef
2212 %B = and %X, undef
2213Safe:
2214 %A = -1
2215 %B = 0
2216Unsafe:
2217 %A = undef
2218 %B = undef
2219</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2220
2221<p>These logical operations have bits that are not always affected by the input.
2222For example, if "%X" has a zero bit, then the output of the 'and' operation will
2223always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2224such, 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]2225However, it is safe to assume that all bits of the undef could be 0, and
2226optimize the and to 0. Likewise, it is safe to assume that all the bits of
2227the 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]2228-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2229
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2230<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2231 %A = select undef, %X, %Y
2232 %B = select undef, 42, %Y
2233 %C = select %X, %Y, undef
2234Safe:
2235 %A = %X (or %Y)
2236 %B = 42 (or %Y)
2237 %C = %Y
2238Unsafe:
2239 %A = undef
2240 %B = undef
2241 %C = undef
2242</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2243
2244<p>This set of examples show that undefined select (and conditional branch)
2245conditions can go "either way" but they have to come from one of the two
2246operands. In the %A example, if %X and %Y were both known to have a clear low
2247bit, then %A would have to have a cleared low bit. However, in the %C example,
2248the optimizer is allowed to assume that the undef operand could be the same as
2249%Y, allowing the whole select to be eliminated.</p>
2250
2251
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2252<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2253 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2254
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2255 %B = undef
2256 %C = xor %B, %B
2257
2258 %D = undef
2259 %E = icmp lt %D, 4
2260 %F = icmp gte %D, 4
2261
2262Safe:
2263 %A = undef
2264 %B = undef
2265 %C = undef
2266 %D = undef
2267 %E = undef
2268 %F = undef
2269</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2270
2271<p>This example points out that two undef operands are not necessarily the same.
2272This can be surprising to people (and also matches C semantics) where they
2273assume that "X^X" is always zero, even if X is undef. This isn't true for a
2274number of reasons, but the short answer is that an undef "variable" can
2275arbitrarily change its value over its "live range". This is true because the
2276"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2277logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2278so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2279to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2280would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2281
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2282<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2283 %A = fdiv undef, %X
2284 %B = fdiv %X, undef
2285Safe:
2286 %A = undef
2287b: unreachable
2288</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2289
2290<p>These examples show the crucial difference between an <em>undefined
2291value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2292allowed to have an arbitrary bit-pattern. This means that the %A operation
2293can be constant folded to undef because the undef could be an SNaN, and fdiv is
2294not (currently) defined on SNaN's. However, in the second example, we can make
2295a more aggressive assumption: because the undef is allowed to be an arbitrary
2296value, 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]2297has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2298does not execute at all. This allows us to delete the divide and all code after
2299it: since the undefined operation "can't happen", the optimizer can assume that
2300it occurs in dead code.
2301</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2302
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2303<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2304a: store undef -> %X
2305b: store %X -> undef
2306Safe:
2307a: &lt;deleted&gt;
2308b: unreachable
2309</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2310
2311<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2312can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2313overwritten with bits that happen to match what was already there. However, a
2314store "to" an undefined location could clobber arbitrary memory, therefore, it
2315has undefined behavior.</p>
2316
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2317</div>
2318
2319<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2320<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2321<div class="doc_text">
2322
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2323<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2324 instead of representing an unspecified bit pattern, they represent the
2325 fact that an instruction or constant expression which cannot evoke side
2326 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2327 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2328
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2329<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]2330 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2331 <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]2332
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2333<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2334
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2335<ul>
2336<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2337 their operands.</li>
2338
2339<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2340 to their dynamic predecessor basic block.</li>
2341
2342<li>Function arguments depend on the corresponding actual argument values in
2343 the dynamic callers of their functions.</li>
2344
2345<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2346 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2347 control back to them.</li>
2348
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2349<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2350 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2351 or exception-throwing call instructions that dynamically transfer control
2352 back to them.</li>
2353
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2354<li>Non-volatile loads and stores depend on the most recent stores to all of the
2355 referenced memory addresses, following the order in the IR
2356 (including loads and stores implied by intrinsics such as
2357 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2358
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2359<!-- TODO: In the case of multiple threads, this only applies if the store
2360 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2361
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2362<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2363
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2364<li>An instruction with externally visible side effects depends on the most
2365 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2366 the order in the IR. (This includes
2367 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2368
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2369<li>An instruction <i>control-depends</i> on a
2370 <a href="#terminators">terminator instruction</a>
2371 if the terminator instruction has multiple successors and the instruction
2372 is always executed when control transfers to one of the successors, and
2373 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2374
2375<li>Dependence is transitive.</li>
2376
2377</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2378
2379<p>Whenever a trap value is generated, all values which depend on it evaluate
2380 to trap. If they have side effects, the evoke their side effects as if each
2381 operand with a trap value were undef. If they have externally-visible side
2382 effects, the behavior is undefined.</p>
2383
2384<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2385
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2386<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2387entry:
2388 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2389 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2390 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2391 store i32 0, i32* %trap_yet_again ; undefined behavior
2392
2393 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2394 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2395
2396 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2397
2398 %narrowaddr = bitcast i32* @g to i16*
2399 %wideaddr = bitcast i32* @g to i64*
2400 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2401 %trap4 = load i64* %widaddr ; Returns a trap value.
2402
2403 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2404 %br i1 %cmp, %true, %end ; Branch to either destination.
2405
2406true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2407 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2408 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2409 br label %end
2410
2411end:
2412 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2413 ; Both edges into this PHI are
2414 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2415 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2416
2417 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2418 ; so this is defined (ignoring earlier
2419 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2420</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2421
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2422</div>
2423
2424<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2425<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2426 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2427<div class="doc_text">
2428
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2429<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2430
2431<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2432 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2433 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2434
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2435<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2436 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2437 against null. Pointer equality tests between labels addresses is undefined
2438 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2439 equal to the null pointer. This may also be passed around as an opaque
2440 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2441 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2442 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2443
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2444<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2445 using the value as the operand to an inline assembly, but that is target
2446 specific.
2447 </p>
2448
2449</div>
2450
2451
2452<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2453<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2454</div>
2455
2456<div class="doc_text">
2457
2458<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2459 to be used as constants. Constant expressions may be of
2460 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2461 operation that does not have side effects (e.g. load and call are not
2462 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2463
2464<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2465 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2466 <dd>Truncate a constant to another type. The bit size of CST must be larger
2467 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2468
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2469 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2470 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2471 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2472
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2473 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2474 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2475 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2476
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2477 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2478 <dd>Truncate a floating point constant to another floating point type. The
2479 size of CST must be larger than the size of TYPE. Both types must be
2480 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2481
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2482 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2483 <dd>Floating point extend a constant to another type. The size of CST must be
2484 smaller or equal to the size of TYPE. Both types must be floating
2485 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2486
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2487 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2489 constant. TYPE must be a scalar or vector integer type. CST must be of
2490 scalar or vector floating point type. Both CST and TYPE must be scalars,
2491 or vectors of the same number of elements. If the value won't fit in the
2492 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2495 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496 constant. TYPE must be a scalar or vector integer type. CST must be of
2497 scalar or vector floating point type. Both CST and TYPE must be scalars,
2498 or vectors of the same number of elements. If the value won't fit in the
2499 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2500
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2501 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2502 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2503 constant. TYPE must be a scalar or vector floating point type. CST must be
2504 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2505 vectors of the same number of elements. If the value won't fit in the
2506 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2507
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2508 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2509 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2510 constant. TYPE must be a scalar or vector floating point type. CST must be
2511 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2512 vectors of the same number of elements. If the value won't fit in the
2513 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2514
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2515 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2516 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2517 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2518 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2519 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2520
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2521 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2522 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2523 type. CST must be of integer type. The CST value is zero extended,
2524 truncated, or unchanged to make it fit in a pointer size. This one is
2525 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2526
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2527 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2528 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2529 are the same as those for the <a href="#i_bitcast">bitcast
2530 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2531
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2532 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2533 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2534 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2535 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2536 instruction, the index list may have zero or more indexes, which are
2537 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2538
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2539 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2540 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2541
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2542 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2543 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2544
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2545 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2546 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2547
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2549 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2550 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2551
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2552 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2554 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2555
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2556 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2558 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2559
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2560 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2561 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2562 constants. The index list is interpreted in a similar manner as indices in
2563 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2564 index value must be specified.</dd>
2565
2566 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2567 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2568 constants. The index list is interpreted in a similar manner as indices in
2569 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2570 index value must be specified.</dd>
2571
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2572 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2573 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2574 be any of the <a href="#binaryops">binary</a>
2575 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2576 on operands are the same as those for the corresponding instruction
2577 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2578</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2579
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2580</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2583<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2584<!-- *********************************************************************** -->
2585
2586<!-- ======================================================================= -->
2587<div class="doc_subsection">
2588<a name="inlineasm">Inline Assembler Expressions</a>
2589</div>
2590
2591<div class="doc_text">
2592
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2593<p>LLVM supports inline assembler expressions (as opposed
2594 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2595 a special value. This value represents the inline assembler as a string
2596 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2597 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2598 expression has side effects, and a flag indicating whether the function
2599 containing the asm needs to align its stack conservatively. An example
2600 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2601
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2602<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2603i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2604</pre>
2605
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2606<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2607 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2608 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2609
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2610<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2611%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]2612</pre>
2613
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2614<p>Inline asms with side effects not visible in the constraint list must be
2615 marked as having side effects. This is done through the use of the
2616 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2617
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2618<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2619call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2620</pre>
2621
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2622<p>In some cases inline asms will contain code that will not work unless the
2623 stack is aligned in some way, such as calls or SSE instructions on x86,
2624 yet will not contain code that does that alignment within the asm.
2625 The compiler should make conservative assumptions about what the asm might
2626 contain and should generate its usual stack alignment code in the prologue
2627 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2628
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2629<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2630call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2631</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2632
2633<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2634 first.</p>
2635
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2636<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2637 documented here. Constraints on what can be done (e.g. duplication, moving,
2638 etc need to be documented). This is probably best done by reference to
2639 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2640</div>
2641
2642<div class="doc_subsubsection">
2643<a name="inlineasm_md">Inline Asm Metadata</a>
2644</div>
2645
2646<div class="doc_text">
2647
2648<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2649 attached to it that contains a constant integer. If present, the code
2650 generator will use the integer as the location cookie value when report
2651 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2652 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2653 source code that produced it. For example:</p>
2654
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2655<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2656call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2657...
2658!42 = !{ i32 1234567 }
2659</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2660
2661<p>It is up to the front-end to make sense of the magic numbers it places in the
2662 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2663
2664</div>
2665
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2666<!-- ======================================================================= -->
2667<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2668 Strings</a>
2669</div>
2670
2671<div class="doc_text">
2672
2673<p>LLVM IR allows metadata to be attached to instructions in the program that
2674 can convey extra information about the code to the optimizers and code
2675 generator. One example application of metadata is source-level debug
2676 information. There are two metadata primitives: strings and nodes. All
2677 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2678 preceding exclamation point ('<tt>!</tt>').</p>
2679
2680<p>A metadata string is a string surrounded by double quotes. It can contain
2681 any character by escaping non-printable characters with "\xx" where "xx" is
2682 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2683
2684<p>Metadata nodes are represented with notation similar to structure constants
2685 (a comma separated list of elements, surrounded by braces and preceded by an
2686 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2687 10}</tt>". Metadata nodes can have any values as their operand.</p>
2688
2689<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2690 metadata nodes, which can be looked up in the module symbol table. For
2691 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2692
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2693<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2694 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2695
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2696 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2697 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2698 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2699
2700<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2701 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2702
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2703 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2704 %indvar.next = add i64 %indvar, 1, !dbg !21
2705 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2706</div>
2707
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2708
2709<!-- *********************************************************************** -->
2710<div class="doc_section">
2711 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2712</div>
2713<!-- *********************************************************************** -->
2714
2715<p>LLVM has a number of "magic" global variables that contain data that affect
2716code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2717of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2718section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2719by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2720
2721<!-- ======================================================================= -->
2722<div class="doc_subsection">
2723<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2724</div>
2725
2726<div class="doc_text">
2727
2728<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2729href="#linkage_appending">appending linkage</a>. This array contains a list of
2730pointers to global variables and functions which may optionally have a pointer
2731cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2732
2733<pre>
2734 @X = global i8 4
2735 @Y = global i32 123
2736
2737 @llvm.used = appending global [2 x i8*] [
2738 i8* @X,
2739 i8* bitcast (i32* @Y to i8*)
2740 ], section "llvm.metadata"
2741</pre>
2742
2743<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2744compiler, assembler, and linker are required to treat the symbol as if there is
2745a reference to the global that it cannot see. For example, if a variable has
2746internal linkage and no references other than that from the <tt>@llvm.used</tt>
2747list, it cannot be deleted. This is commonly used to represent references from
2748inline asms and other things the compiler cannot "see", and corresponds to
2749"attribute((used))" in GNU C.</p>
2750
2751<p>On some targets, the code generator must emit a directive to the assembler or
2752object file to prevent the assembler and linker from molesting the symbol.</p>
2753
2754</div>
2755
2756<!-- ======================================================================= -->
2757<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2758<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2759</div>
2760
2761<div class="doc_text">
2762
2763<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2764<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2765touching the symbol. On targets that support it, this allows an intelligent
2766linker to optimize references to the symbol without being impeded as it would be
2767by <tt>@llvm.used</tt>.</p>
2768
2769<p>This is a rare construct that should only be used in rare circumstances, and
2770should not be exposed to source languages.</p>
2771
2772</div>
2773
2774<!-- ======================================================================= -->
2775<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2776<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2777</div>
2778
2779<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2780<pre>
2781%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2782@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2783</pre>
2784<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.
2785</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2786
2787</div>
2788
2789<!-- ======================================================================= -->
2790<div class="doc_subsection">
2791<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2792</div>
2793
2794<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2795<pre>
2796%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2797@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2798</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2799
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2800<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.
2801</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2802
2803</div>
2804
2805
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2806<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2807<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2808<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2809
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2810<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2812<p>The LLVM instruction set consists of several different classifications of
2813 instructions: <a href="#terminators">terminator
2814 instructions</a>, <a href="#binaryops">binary instructions</a>,
2815 <a href="#bitwiseops">bitwise binary instructions</a>,
2816 <a href="#memoryops">memory instructions</a>, and
2817 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2818
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2819</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2821<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2822<div class="doc_subsection"> <a name="terminators">Terminator
2823Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2825<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2826
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2827<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2828 in a program ends with a "Terminator" instruction, which indicates which
2829 block should be executed after the current block is finished. These
2830 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2831 control flow, not values (the one exception being the
2832 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2833
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2834<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2835 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2836 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2837 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2838 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2839 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2840 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2841 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2842
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2843</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2845<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2846<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2847Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2848
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2849<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2852<pre>
2853 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]2854 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2857<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2859 a value) from a function back to the caller.</p>
2860
2861<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2862 value and then causes control flow, and one that just causes control flow to
2863 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2867 return value. The type of the return value must be a
2868 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2871 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2872 value or a return value with a type that does not match its type, or if it
2873 has a void return type and contains a '<tt>ret</tt>' instruction with a
2874 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2878 the calling function's context. If the caller is a
2879 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2880 instruction after the call. If the caller was an
2881 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2882 the beginning of the "normal" destination block. If the instruction returns
2883 a value, that value shall set the call or invoke instruction's return
2884 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2887<pre>
2888 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2889 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2890 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]2891</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2893</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2894<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2895<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2896
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2897<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2900<pre>
2901 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]2902</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2905<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2906 different basic block in the current function. There are two forms of this
2907 instruction, corresponding to a conditional branch and an unconditional
2908 branch.</p>
2909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2910<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2911<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2912 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2913 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2914 target.</p>
2915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2916<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2917<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2918 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2919 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2920 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2923<pre>
2924Test:
2925 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2926 br i1 %cond, label %IfEqual, label %IfUnequal
2927IfEqual:
2928 <a href="#i_ret">ret</a> i32 1
2929IfUnequal:
2930 <a href="#i_ret">ret</a> i32 0
2931</pre>
2932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2933</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2935<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2936<div class="doc_subsubsection">
2937 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2938</div>
2939
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2940<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2941
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2942<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2943<pre>
2944 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2945</pre>
2946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2947<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2948<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]2949 several different places. It is a generalization of the '<tt>br</tt>'
2950 instruction, allowing a branch to occur to one of many possible
2951 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2952
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2953<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2954<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2955 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2956 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2957 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2958
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2959<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2960<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2962 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2963 transferred to the corresponding destination; otherwise, control flow is
2964 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2965
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2966<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2967<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2968 <tt>switch</tt> instruction, this instruction may be code generated in
2969 different ways. For example, it could be generated as a series of chained
2970 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2971
2972<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2973<pre>
2974 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2975 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2976 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977
2978 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2979 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2980
2981 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2982 switch i32 %val, label %otherwise [ i32 0, label %onzero
2983 i32 1, label %onone
2984 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2985</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2986
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2987</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2988
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2989
2990<!-- _______________________________________________________________________ -->
2991<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2992 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2993</div>
2994
2995<div class="doc_text">
2996
2997<h5>Syntax:</h5>
2998<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2999 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]3000</pre>
3001
3002<h5>Overview:</h5>
3003
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3004<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3005 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3006 "<tt>address</tt>". Address must be derived from a <a
3007 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3008
3009<h5>Arguments:</h5>
3010
3011<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3012 rest of the arguments indicate the full set of possible destinations that the
3013 address may point to. Blocks are allowed to occur multiple times in the
3014 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3015
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3016<p>This destination list is required so that dataflow analysis has an accurate
3017 understanding of the CFG.</p>
3018
3019<h5>Semantics:</h5>
3020
3021<p>Control transfers to the block specified in the address argument. All
3022 possible destination blocks must be listed in the label list, otherwise this
3023 instruction has undefined behavior. This implies that jumps to labels
3024 defined in other functions have undefined behavior as well.</p>
3025
3026<h5>Implementation:</h5>
3027
3028<p>This is typically implemented with a jump through a register.</p>
3029
3030<h5>Example:</h5>
3031<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3032 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3033</pre>
3034
3035</div>
3036
3037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3038<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3039<div class="doc_subsubsection">
3040 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3041</div>
3042
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3043<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3045<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3046<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3047 &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]3048 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049</pre>
3050
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3051<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3052<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3053 function, with the possibility of control flow transfer to either the
3054 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3055 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3056 control flow will return to the "normal" label. If the callee (or any
3057 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3058 instruction, control is interrupted and continued at the dynamically nearest
3059 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3061<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3062<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3063
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3064<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3066 convention</a> the call should use. If none is specified, the call
3067 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3068
3069 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3071 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3072
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073 <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]3074 function value being invoked. In most cases, this is a direct function
3075 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3076 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3077
3078 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3079 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3080
3081 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3082 signature argument types and parameter attributes. All arguments must be
3083 of <a href="#t_firstclass">first class</a> type. If the function
3084 signature indicates the function accepts a variable number of arguments,
3085 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3086
3087 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3089
3090 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3091 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3092
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3093 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3094 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3095 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3096</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3097
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3098<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3099<p>This instruction is designed to operate as a standard
3100 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3101 primary difference is that it establishes an association with a label, which
3102 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3103
3104<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3105 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3106 exception. Additionally, this is important for implementation of
3107 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3108
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<p>For the purposes of the SSA form, the definition of the value returned by the
3110 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3111 block to the "normal" label. If the callee unwinds then no return value is
3112 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3113
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3114<p>Note that the code generator does not yet completely support unwind, and
3115that the invoke/unwind semantics are likely to change in future versions.</p>
3116
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3117<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3118<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3119 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3120 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3121 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3122 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3123</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3124
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3125</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3126
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3127<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3128
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3129<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3130Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3131
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3132<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3133
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3134<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3135<pre>
3136 unwind
3137</pre>
3138
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3139<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3140<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3141 at the first callee in the dynamic call stack which used
3142 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3143 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3144
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3145<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3146<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3147 immediately halt. The dynamic call stack is then searched for the
3148 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3149 Once found, execution continues at the "exceptional" destination block
3150 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3151 instruction in the dynamic call chain, undefined behavior results.</p>
3152
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3153<p>Note that the code generator does not yet completely support unwind, and
3154that the invoke/unwind semantics are likely to change in future versions.</p>
3155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3156</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3157
3158<!-- _______________________________________________________________________ -->
3159
3160<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3161Instruction</a> </div>
3162
3163<div class="doc_text">
3164
3165<h5>Syntax:</h5>
3166<pre>
3167 unreachable
3168</pre>
3169
3170<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3171<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172 instruction is used to inform the optimizer that a particular portion of the
3173 code is not reachable. This can be used to indicate that the code after a
3174 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3175
3176<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3177<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3178
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3179</div>
3180
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3181<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3182<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3183
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3184<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3185
3186<p>Binary operators are used to do most of the computation in a program. They
3187 require two operands of the same type, execute an operation on them, and
3188 produce a single value. The operands might represent multiple data, as is
3189 the case with the <a href="#t_vector">vector</a> data type. The result value
3190 has the same type as its operands.</p>
3191
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3192<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3193
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3194</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3197<div class="doc_subsubsection">
3198 <a name="i_add">'<tt>add</tt>' Instruction</a>
3199</div>
3200
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3201<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3203<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3204<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3205 &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]3206 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3207 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3208 &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]3209</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3212<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3213
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3214<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215<p>The two arguments to the '<tt>add</tt>' instruction must
3216 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3217 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3218
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3219<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3220<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3221
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222<p>If the sum has unsigned overflow, the result returned is the mathematical
3223 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]3224
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3225<p>Because LLVM integers use a two's complement representation, this instruction
3226 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3227
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3228<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3229 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3230 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3231 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3232 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3234<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3235<pre>
3236 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3239</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3241<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3242<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3243 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3244</div>
3245
3246<div class="doc_text">
3247
3248<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3249<pre>
3250 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3251</pre>
3252
3253<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3254<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3255
3256<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3257<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3258 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3259 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3260
3261<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3262<p>The value produced is the floating point sum of the two operands.</p>
3263
3264<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3265<pre>
3266 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3267</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3269</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3270
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3271<!-- _______________________________________________________________________ -->
3272<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3273 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3274</div>
3275
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3276<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3278<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3279<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3280 &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]3281 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3282 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3283 &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]3284</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3285
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3286<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3287<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3288 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289
3290<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3291 '<tt>neg</tt>' instruction present in most other intermediate
3292 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3294<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3295<p>The two arguments to the '<tt>sub</tt>' instruction must
3296 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3297 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3299<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3300<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3301
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3302<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3303 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3304 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3305
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3306<p>Because LLVM integers use a two's complement representation, this instruction
3307 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3308
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3309<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3310 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3311 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3312 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3313 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3315<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3316<pre>
3317 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3318 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3319</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3321</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3323<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3324<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3325 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3326</div>
3327
3328<div class="doc_text">
3329
3330<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3331<pre>
3332 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3333</pre>
3334
3335<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3336<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3337 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3338
3339<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3340 '<tt>fneg</tt>' instruction present in most other intermediate
3341 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3342
3343<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3344<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3345 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3346 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3347
3348<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3349<p>The value produced is the floating point difference of the two operands.</p>
3350
3351<h5>Example:</h5>
3352<pre>
3353 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3354 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3355</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3356
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3357</div>
3358
3359<!-- _______________________________________________________________________ -->
3360<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3361 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3362</div>
3363
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3364<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3366<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3368 &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]3369 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3370 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3371 &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]3372</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3375<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3377<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3378<p>The two arguments to the '<tt>mul</tt>' instruction must
3379 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3380 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3381
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3382<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3383<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3384
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385<p>If the result of the multiplication has unsigned overflow, the result
3386 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3387 width of the result.</p>
3388
3389<p>Because LLVM integers use a two's complement representation, and the result
3390 is the same width as the operands, this instruction returns the correct
3391 result for both signed and unsigned integers. If a full product
3392 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3393 be sign-extended or zero-extended as appropriate to the width of the full
3394 product.</p>
3395
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3396<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3397 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3398 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3399 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3400 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3402<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403<pre>
3404 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3405</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3406
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3407</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3408
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3409<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3410<div class="doc_subsubsection">
3411 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3412</div>
3413
3414<div class="doc_text">
3415
3416<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417<pre>
3418 &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]3419</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3421<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3423
3424<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3425<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3427 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3428
3429<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3430<p>The value produced is the floating point product of the two operands.</p>
3431
3432<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433<pre>
3434 &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]3435</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3437</div>
3438
3439<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3440<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3441</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3443<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3445<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446<pre>
3447 &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]3448</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3454<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3456 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3457
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3459<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3461<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3463
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3464<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3466<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467<pre>
3468 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3469</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3471</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3473<!-- _______________________________________________________________________ -->
3474<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3475</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3476
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3477<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3479<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3480<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3481 &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]3482 &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]3483</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3484
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3487
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3488<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3489<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3491 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3492
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3493<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494<p>The value produced is the signed integer quotient of the two operands rounded
3495 towards zero.</p>
3496
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3497<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3499
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3500<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501 undefined behavior; this is a rare case, but can occur, for example, by doing
3502 a 32-bit division of -2147483648 by -1.</p>
3503
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3504<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3505 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3506 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3507
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3508<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3509<pre>
3510 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3511</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3513</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3514
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3515<!-- _______________________________________________________________________ -->
3516<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3517Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3519<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3521<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3523 &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]3524</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526<h5>Overview:</h5>
3527<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3528
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3529<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3530<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3532 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3533
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3534<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3535<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3536
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3537<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3538<pre>
3539 &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]3540</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3542</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3544<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3545<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3546</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3548<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3550<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551<pre>
3552 &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]3553</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3555<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3557 division of its two arguments.</p>
3558
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3559<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3560<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3562 values. Both arguments must have identical types.</p>
3563
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3564<h5>Semantics:</h5>
3565<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566 This instruction always performs an unsigned division to get the
3567 remainder.</p>
3568
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3569<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3571
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3572<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575<pre>
3576 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3577</pre>
3578
3579</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3581<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3582<div class="doc_subsubsection">
3583 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3584</div>
3585
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3586<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3587
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3588<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3590 &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]3591</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3592
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3593<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3595 division of its two operands. This instruction can also take
3596 <a href="#t_vector">vector</a> versions of the values in which case the
3597 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3598
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3599<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3600<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3601 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3602 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3603
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3604<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3605<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3607 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3608 a value. For more information about the difference,
3609 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3610 Math Forum</a>. For a table of how this is implemented in various languages,
3611 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3612 Wikipedia: modulo operation</a>.</p>
3613
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3614<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3616
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3617<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618 Overflow also leads to undefined behavior; this is a rare case, but can
3619 occur, for example, by taking the remainder of a 32-bit division of
3620 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3621 lets srem be implemented using instructions that return both the result of
3622 the division and the remainder.)</p>
3623
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3624<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625<pre>
3626 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3627</pre>
3628
3629</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3630
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3631<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3632<div class="doc_subsubsection">
3633 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3634
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3635<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3636
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3637<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3638<pre>
3639 &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]3640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3642<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3644 its two operands.</p>
3645
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3646<h5>Arguments:</h5>
3647<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3649 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3650
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3651<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3652<p>This instruction returns the <i>remainder</i> of a division. The remainder
3653 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3654
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3655<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3656<pre>
3657 &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]3658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3660</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3661
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3662<!-- ======================================================================= -->
3663<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3664Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3666<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667
3668<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3669 program. They are generally very efficient instructions and can commonly be
3670 strength reduced from other instructions. They require two operands of the
3671 same type, execute an operation on them, and produce a single value. The
3672 resulting value is the same type as its operands.</p>
3673
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3674</div>
3675
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3678Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3680<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3682<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683<pre>
3684 &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]3685</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3686
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3687<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3689 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3690
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3691<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3693 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3694 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3695
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3696<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3698 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3699 is (statically or dynamically) negative or equal to or larger than the number
3700 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3701 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3702 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3703
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704<h5>Example:</h5>
3705<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3706 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3707 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3708 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3709 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3710 &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]3711</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3713</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3715<!-- _______________________________________________________________________ -->
3716<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3717Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3719<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3721<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722<pre>
3723 &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]3724</pre>
3725
3726<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3727<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3728 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3729
3730<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3731<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3733 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3734
3735<h5>Semantics:</h5>
3736<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737 significant bits of the result will be filled with zero bits after the shift.
3738 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3739 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3740 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3741 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3742
3743<h5>Example:</h5>
3744<pre>
3745 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3746 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3747 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3748 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3749 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3750 &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]3751</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3752
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753</div>
3754
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3755<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3756<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3757Instruction</a> </div>
3758<div class="doc_text">
3759
3760<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761<pre>
3762 &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]3763</pre>
3764
3765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3767 operand shifted to the right a specified number of bits with sign
3768 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3769
3770<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3771<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3773 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3774
3775<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>This instruction always performs an arithmetic shift right operation, The
3777 most significant bits of the result will be filled with the sign bit
3778 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3779 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3780 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3781 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3782
3783<h5>Example:</h5>
3784<pre>
3785 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3786 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3787 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3788 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3789 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3790 &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]3791</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3792
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3793</div>
3794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3795<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3796<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3797Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3799<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3801<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3802<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3803 &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]3804</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3806<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3807<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3808 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3810<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3811<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3812 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3813 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3814
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3815<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3816<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3818<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3819 <tbody>
3820 <tr>
3821 <td>In0</td>
3822 <td>In1</td>
3823 <td>Out</td>
3824 </tr>
3825 <tr>
3826 <td>0</td>
3827 <td>0</td>
3828 <td>0</td>
3829 </tr>
3830 <tr>
3831 <td>0</td>
3832 <td>1</td>
3833 <td>0</td>
3834 </tr>
3835 <tr>
3836 <td>1</td>
3837 <td>0</td>
3838 <td>0</td>
3839 </tr>
3840 <tr>
3841 <td>1</td>
3842 <td>1</td>
3843 <td>1</td>
3844 </tr>
3845 </tbody>
3846</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3849<pre>
3850 &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]3851 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3852 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3853</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3854</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3855<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3856<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3857
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858<div class="doc_text">
3859
3860<h5>Syntax:</h5>
3861<pre>
3862 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3863</pre>
3864
3865<h5>Overview:</h5>
3866<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3867 two operands.</p>
3868
3869<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3870<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3871 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3872 values. Both arguments must have identical types.</p>
3873
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3874<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3875<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3876
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3877<table border="1" cellspacing="0" cellpadding="4">
3878 <tbody>
3879 <tr>
3880 <td>In0</td>
3881 <td>In1</td>
3882 <td>Out</td>
3883 </tr>
3884 <tr>
3885 <td>0</td>
3886 <td>0</td>
3887 <td>0</td>
3888 </tr>
3889 <tr>
3890 <td>0</td>
3891 <td>1</td>
3892 <td>1</td>
3893 </tr>
3894 <tr>
3895 <td>1</td>
3896 <td>0</td>
3897 <td>1</td>
3898 </tr>
3899 <tr>
3900 <td>1</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 </tbody>
3905</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<pre>
3909 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3910 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3911 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3912</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3914</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3915
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_xor">'<tt>xor</tt>'
3918Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3920<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3922<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923<pre>
3924 &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]3925</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3927<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3929 its two operands. The <tt>xor</tt> is used to implement the "one's
3930 complement" operation, which is the "~" operator in C.</p>
3931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3932<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3933<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3934 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3935 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3938<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3940<table border="1" cellspacing="0" cellpadding="4">
3941 <tbody>
3942 <tr>
3943 <td>In0</td>
3944 <td>In1</td>
3945 <td>Out</td>
3946 </tr>
3947 <tr>
3948 <td>0</td>
3949 <td>0</td>
3950 <td>0</td>
3951 </tr>
3952 <tr>
3953 <td>0</td>
3954 <td>1</td>
3955 <td>1</td>
3956 </tr>
3957 <tr>
3958 <td>1</td>
3959 <td>0</td>
3960 <td>1</td>
3961 </tr>
3962 <tr>
3963 <td>1</td>
3964 <td>1</td>
3965 <td>0</td>
3966 </tr>
3967 </tbody>
3968</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3970<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971<pre>
3972 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3973 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3974 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3975 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3976</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3978</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3980<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3981<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3982 <a name="vectorops">Vector Operations</a>
3983</div>
3984
3985<div class="doc_text">
3986
3987<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988 target-independent manner. These instructions cover the element-access and
3989 vector-specific operations needed to process vectors effectively. While LLVM
3990 does directly support these vector operations, many sophisticated algorithms
3991 will want to use target-specific intrinsics to take full advantage of a
3992 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3993
3994</div>
3995
3996<!-- _______________________________________________________________________ -->
3997<div class="doc_subsubsection">
3998 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3999</div>
4000
4001<div class="doc_text">
4002
4003<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4004<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4005 &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]4006</pre>
4007
4008<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4010 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4011
4012
4013<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4015 of <a href="#t_vector">vector</a> type. The second operand is an index
4016 indicating the position from which to extract the element. The index may be
4017 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4018
4019<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020<p>The result is a scalar of the same type as the element type of
4021 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4022 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4023 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4024
4025<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4026<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4027 &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]4028</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4031
4032<!-- _______________________________________________________________________ -->
4033<div class="doc_subsubsection">
4034 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4035</div>
4036
4037<div class="doc_text">
4038
4039<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4040<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4041 &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]4042</pre>
4043
4044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4046 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4047
4048<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4050 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4051 whose type must equal the element type of the first operand. The third
4052 operand is an index indicating the position at which to insert the value.
4053 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4054
4055<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4056<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4057 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4058 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4059 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4060
4061<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4062<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4063 &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]4064</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4066</div>
4067
4068<!-- _______________________________________________________________________ -->
4069<div class="doc_subsubsection">
4070 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4071</div>
4072
4073<div class="doc_text">
4074
4075<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4076<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4077 &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]4078</pre>
4079
4080<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4082 from two input vectors, returning a vector with the same element type as the
4083 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4084
4085<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4087 with types that match each other. The third argument is a shuffle mask whose
4088 element type is always 'i32'. The result of the instruction is a vector
4089 whose length is the same as the shuffle mask and whose element type is the
4090 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4092<p>The shuffle mask operand is required to be a constant vector with either
4093 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The elements of the two input vectors are numbered from left to right across
4097 both of the vectors. The shuffle mask operand specifies, for each element of
4098 the result vector, which element of the two input vectors the result element
4099 gets. The element selector may be undef (meaning "don't care") and the
4100 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4101
4102<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4103<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4104 &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]4105 &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]4106 &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]4107 &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]4108 &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]4109 &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]4110 &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]4111 &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]4112</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4114</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4115
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4116<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4117<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4118 <a name="aggregateops">Aggregate Operations</a>
4119</div>
4120
4121<div class="doc_text">
4122
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4123<p>LLVM supports several instructions for working with
4124 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4125
4126</div>
4127
4128<!-- _______________________________________________________________________ -->
4129<div class="doc_subsubsection">
4130 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4131</div>
4132
4133<div class="doc_text">
4134
4135<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4136<pre>
4137 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4138</pre>
4139
4140<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4141<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4142 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4143
4144<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4146 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4147 <a href="#t_array">array</a> type. The operands are constant indices to
4148 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4150
4151<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4152<p>The result is the value at the position in the aggregate specified by the
4153 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4154
4155<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4156<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4157 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4158</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4160</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161
4162<!-- _______________________________________________________________________ -->
4163<div class="doc_subsubsection">
4164 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4165</div>
4166
4167<div class="doc_text">
4168
4169<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4170<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4171 &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]4172</pre>
4173
4174<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4175<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4176 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4177
4178<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4180 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4181 <a href="#t_array">array</a> type. The second operand is a first-class
4182 value to insert. The following operands are constant indices indicating
4183 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]4184 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4185 value to insert must have the same type as the value identified by the
4186 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4187
4188<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4190 that of <tt>val</tt> except that the value at the position specified by the
4191 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4192
4193<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4194<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4195 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4196 %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]4197</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4198
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4199</div>
4200
4201
4202<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4203<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4204 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4205</div>
4206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4207<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4208
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209<p>A key design point of an SSA-based representation is how it represents
4210 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4211 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4213
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4214</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4216<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4217<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4218 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4219</div>
4220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4221<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4223<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4224<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4225 &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]4226</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4227
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4228<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4229<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230 currently executing function, to be automatically released when this function
4231 returns to its caller. The object is always allocated in the generic address
4232 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>alloca</tt>' instruction
4236 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4237 runtime stack, returning a pointer of the appropriate type to the program.
4238 If "NumElements" is specified, it is the number of elements allocated,
4239 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4240 specified, the value result of the allocation is guaranteed to be aligned to
4241 at least that boundary. If not specified, or if zero, the target can choose
4242 to align the allocation on any convenient boundary compatible with the
4243 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4245<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4247<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4248<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4250 memory is automatically released when the function returns. The
4251 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4252 variables that must have an address available. When the function returns
4253 (either with the <tt><a href="#i_ret">ret</a></tt>
4254 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4255 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4257<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4258<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4259 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4260 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4261 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4262 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4263</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4264
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4265</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4267<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4268<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4269Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4271<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4272
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4273<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4275 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4276 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4277 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278</pre>
4279
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4280<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4281<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4285 from which to load. The pointer must point to
4286 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4287 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4288 number or order of execution of this <tt>load</tt> with other <a
4289 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4290
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4291<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292 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]4293 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294 alignment for the target. It is the responsibility of the code emitter to
4295 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4296 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297 produce less efficient code. An alignment of 1 is always safe.</p>
4298
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4299<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4300 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4301 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4302 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4303 and code generator that this load is not expected to be reused in the cache.
4304 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4305 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4306
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4307<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308<p>The location of memory pointed to is loaded. If the value being loaded is of
4309 scalar type then the number of bytes read does not exceed the minimum number
4310 of bytes needed to hold all bits of the type. For example, loading an
4311 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4312 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4313 is undefined if the value was not originally written using a store of the
4314 same type.</p>
4315
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4316<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4317<pre>
4318 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4319 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4320 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4321</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4323</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4325<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4326<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4327Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4328
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4329<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4331<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4332<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4333 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4334 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4335</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4336
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4337<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4338<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4340<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4342 and an address at which to store it. The type of the
4343 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4344 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4345 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4346 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4347 order of execution of this <tt>store</tt> with other <a
4348 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349
4350<p>The optional constant "align" argument specifies the alignment of the
4351 operation (that is, the alignment of the memory address). A value of 0 or an
4352 omitted "align" argument means that the operation has the preferential
4353 alignment for the target. It is the responsibility of the code emitter to
4354 ensure that the alignment information is correct. Overestimating the
4355 alignment results in an undefined behavior. Underestimating the alignment may
4356 produce less efficient code. An alignment of 1 is always safe.</p>
4357
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4358<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4359 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4360 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4361 instruction tells the optimizer and code generator that this load is
4362 not expected to be reused in the cache. The code generator may
4363 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4364 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4365
4366
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4367<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4369 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4370 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4371 does not exceed the minimum number of bytes needed to hold all bits of the
4372 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4373 writing a value of a type like <tt>i20</tt> with a size that is not an
4374 integral number of bytes, it is unspecified what happens to the extra bits
4375 that do not belong to the type, but they will typically be overwritten.</p>
4376
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4377<h5>Example:</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>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4380 store i32 3, i32* %ptr <i>; yields {void}</i>
4381 %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]4382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4384</div>
4385
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4386<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4387<div class="doc_subsubsection">
4388 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4389</div>
4390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4391<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4392
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4393<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4394<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4395 &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]4396 &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]4397</pre>
4398
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4399<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4401 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4402 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4403
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4404<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4405<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4406 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4407 elements of the aggregate object are indexed. The interpretation of each
4408 index is dependent on the type being indexed into. The first index always
4409 indexes the pointer value given as the first argument, the second index
4410 indexes a value of the type pointed to (not necessarily the value directly
4411 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4412 indexed into must be a pointer value, subsequent types can be arrays,
4413 vectors, structs and unions. Note that subsequent types being indexed into
4414 can never be pointers, since that would require loading the pointer before
4415 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4416
4417<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]4418 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4419 integer <b>constants</b> are allowed. When indexing into an array, pointer
4420 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]4421 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4422
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4423<p>For example, let's consider a C code fragment and how it gets compiled to
4424 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4425
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4426<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4427struct RT {
4428 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4429 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4430 char C;
4431};
4432struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4433 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4434 double Y;
4435 struct RT Z;
4436};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4437
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4438int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4439 return &amp;s[1].Z.B[5][13];
4440}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4441</pre>
4442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4443<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4445<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4446%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4447%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4448
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4449define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4450entry:
4451 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4452 ret i32* %reg
4453}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4454</pre>
4455
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4456<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4457<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]4458 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4459 }</tt>' type, a structure. The second index indexes into the third element
4460 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4461 i8 }</tt>' type, another structure. The third index indexes into the second
4462 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4463 array. The two dimensions of the array are subscripted into, yielding an
4464 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4465 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4466
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4467<p>Note that it is perfectly legal to index partially through a structure,
4468 returning a pointer to an inner element. Because of this, the LLVM code for
4469 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4470
4471<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4472 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4473 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4474 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4475 %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]4476 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4477 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4478 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4479 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4480</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4481
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4482<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4483 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4484 base pointer is not an <i>in bounds</i> address of an allocated object,
4485 or if any of the addresses that would be formed by successive addition of
4486 the offsets implied by the indices to the base address with infinitely
4487 precise arithmetic are not an <i>in bounds</i> address of that allocated
4488 object. The <i>in bounds</i> addresses for an allocated object are all
4489 the addresses that point into the object, plus the address one byte past
4490 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4491
4492<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4493 the base address with silently-wrapping two's complement arithmetic, and
4494 the result value of the <tt>getelementptr</tt> may be outside the object
4495 pointed to by the base pointer. The result value may not necessarily be
4496 used to access memory though, even if it happens to point into allocated
4497 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4498 section for more information.</p>
4499
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500<p>The getelementptr instruction is often confusing. For some more insight into
4501 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4502
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4503<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4504<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4505 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4506 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4507 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4508 %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]4509 <i>; yields i8*:eptr</i>
4510 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4511 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4512 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4513</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4515</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4516
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4517<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4518<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4519</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4520
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4521<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4522
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4523<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4524 which all take a single operand and a type. They perform various bit
4525 conversions on the operand.</p>
4526
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4527</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4528
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4529<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4530<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4531 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4532</div>
4533<div class="doc_text">
4534
4535<h5>Syntax:</h5>
4536<pre>
4537 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4538</pre>
4539
4540<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4541<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4542 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4543
4544<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4545<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4546 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4547 size and type of the result, which must be
4548 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4549 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4550 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4551
4552<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4553<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4554 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4555 source size must be larger than the destination size, <tt>trunc</tt> cannot
4556 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4557
4558<h5>Example:</h5>
4559<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4560 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4561 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4562 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4565</div>
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4570</div>
4571<div class="doc_text">
4572
4573<h5>Syntax:</h5>
4574<pre>
4575 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4576</pre>
4577
4578<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4579<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4580 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4581
4582
4583<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4584<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]4585 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4586 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]4587 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4588 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4589
4590<h5>Semantics:</h5>
4591<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]4592 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4593
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4594<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]4595
4596<h5>Example:</h5>
4597<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4598 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4599 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4600</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4601
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4602</div>
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4607</div>
4608<div class="doc_text">
4609
4610<h5>Syntax:</h5>
4611<pre>
4612 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4613</pre>
4614
4615<h5>Overview:</h5>
4616<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4617
4618<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4619<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]4620 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4621 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]4622 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4623 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4627 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4628 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4629
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4630<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]4631
4632<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4633<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4634 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4635 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4636</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4638</div>
4639
4640<!-- _______________________________________________________________________ -->
4641<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4642 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4643</div>
4644
4645<div class="doc_text">
4646
4647<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4648<pre>
4649 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4650</pre>
4651
4652<h5>Overview:</h5>
4653<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4655
4656<h5>Arguments:</h5>
4657<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4659 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]4660 <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]4661 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4662
4663<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4665 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666 <a href="#t_floating">floating point</a> type. If the value cannot fit
4667 within the destination type, <tt>ty2</tt>, then the results are
4668 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4669
4670<h5>Example:</h5>
4671<pre>
4672 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4673 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4674</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4676</div>
4677
4678<!-- _______________________________________________________________________ -->
4679<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4680 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4681</div>
4682<div class="doc_text">
4683
4684<h5>Syntax:</h5>
4685<pre>
4686 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4687</pre>
4688
4689<h5>Overview:</h5>
4690<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]4691 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4692
4693<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4694<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4695 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4696 a <a href="#t_floating">floating point</a> type to cast it to. The source
4697 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4698
4699<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4700<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4701 <a href="#t_floating">floating point</a> type to a larger
4702 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4703 used to make a <i>no-op cast</i> because it always changes bits. Use
4704 <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]4705
4706<h5>Example:</h5>
4707<pre>
4708 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4709 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4710</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4711
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4712</div>
4713
4714<!-- _______________________________________________________________________ -->
4715<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4716 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4717</div>
4718<div class="doc_text">
4719
4720<h5>Syntax:</h5>
4721<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4722 &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]4723</pre>
4724
4725<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4726<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4728
4729<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4731 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4732 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4733 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4734 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4735
4736<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4737<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4739 towards zero) unsigned integer value. If the value cannot fit
4740 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4741
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4742<h5>Example:</h5>
4743<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4744 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4745 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4746 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4747</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4749</div>
4750
4751<!-- _______________________________________________________________________ -->
4752<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4753 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4754</div>
4755<div class="doc_text">
4756
4757<h5>Syntax:</h5>
4758<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4759 &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]4760</pre>
4761
4762<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4763<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764 <a href="#t_floating">floating point</a> <tt>value</tt> to
4765 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4766
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4767<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4768<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4769 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4770 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4771 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4772 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4773
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4774<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4775<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4777 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4778 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4779
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4780<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4781<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4782 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4783 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4784 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4785</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4787</div>
4788
4789<!-- _______________________________________________________________________ -->
4790<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4791 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4792</div>
4793<div class="doc_text">
4794
4795<h5>Syntax:</h5>
4796<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4797 &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]4798</pre>
4799
4800<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4801<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4803
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4804<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4805<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]4806 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4807 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4808 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4809 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4810
4811<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4812<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813 integer quantity and converts it to the corresponding floating point
4814 value. If the value cannot fit in the floating point value, the results are
4815 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4816
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4817<h5>Example:</h5>
4818<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4819 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4820 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4821</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4822
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4823</div>
4824
4825<!-- _______________________________________________________________________ -->
4826<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4827 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4828</div>
4829<div class="doc_text">
4830
4831<h5>Syntax:</h5>
4832<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4833 &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]4834</pre>
4835
4836<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4837<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4838 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4839
4840<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4841<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]4842 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4843 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4844 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4845 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4846
4847<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4849 quantity and converts it to the corresponding floating point value. If the
4850 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4851
4852<h5>Example:</h5>
4853<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4854 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4855 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4856</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4857
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4858</div>
4859
4860<!-- _______________________________________________________________________ -->
4861<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4862 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4863</div>
4864<div class="doc_text">
4865
4866<h5>Syntax:</h5>
4867<pre>
4868 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4869</pre>
4870
4871<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4872<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4873 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4874
4875<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4876<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4877 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4878 <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]4879
4880<h5>Semantics:</h5>
4881<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4883 truncating or zero extending that value to the size of the integer type. If
4884 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4885 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4886 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4887 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4888
4889<h5>Example:</h5>
4890<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4891 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4892 %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]4893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4895</div>
4896
4897<!-- _______________________________________________________________________ -->
4898<div class="doc_subsubsection">
4899 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4900</div>
4901<div class="doc_text">
4902
4903<h5>Syntax:</h5>
4904<pre>
4905 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4906</pre>
4907
4908<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4909<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4910 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4911
4912<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4913<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4914 value to cast, and a type to cast it to, which must be a
4915 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4916
4917<h5>Semantics:</h5>
4918<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4919 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4920 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4921 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4922 than the size of a pointer then a zero extension is done. If they are the
4923 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4924
4925<h5>Example:</h5>
4926<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4927 %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]4928 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4929 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4930</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4932</div>
4933
4934<!-- _______________________________________________________________________ -->
4935<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4936 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4937</div>
4938<div class="doc_text">
4939
4940<h5>Syntax:</h5>
4941<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4942 &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]4943</pre>
4944
4945<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4946<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4947 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4948
4949<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4950<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4951 non-aggregate first class value, and a type to cast it to, which must also be
4952 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4953 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4954 identical. If the source type is a pointer, the destination type must also be
4955 a pointer. This instruction supports bitwise conversion of vectors to
4956 integers and to vectors of other types (as long as they have the same
4957 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4958
4959<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4960<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4961 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4962 this conversion. The conversion is done as if the <tt>value</tt> had been
4963 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4964 be converted to other pointer types with this instruction. To convert
4965 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4966 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4967
4968<h5>Example:</h5>
4969<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4970 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4971 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4972 %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]4973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4975</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4976
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4977<!-- ======================================================================= -->
4978<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4980<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981
4982<p>The instructions in this category are the "miscellaneous" instructions, which
4983 defy better classification.</p>
4984
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4985</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4986
4987<!-- _______________________________________________________________________ -->
4988<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4989</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4990
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4991<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4992
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4993<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4994<pre>
4995 &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]4996</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4998<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4999<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5000 boolean values based on comparison of its two integer, integer vector, or
5001 pointer operands.</p>
5002
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5003<h5>Arguments:</h5>
5004<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5005 the condition code indicating the kind of comparison to perform. It is not a
5006 value, just a keyword. The possible condition code are:</p>
5007
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5008<ol>
5009 <li><tt>eq</tt>: equal</li>
5010 <li><tt>ne</tt>: not equal </li>
5011 <li><tt>ugt</tt>: unsigned greater than</li>
5012 <li><tt>uge</tt>: unsigned greater or equal</li>
5013 <li><tt>ult</tt>: unsigned less than</li>
5014 <li><tt>ule</tt>: unsigned less or equal</li>
5015 <li><tt>sgt</tt>: signed greater than</li>
5016 <li><tt>sge</tt>: signed greater or equal</li>
5017 <li><tt>slt</tt>: signed less than</li>
5018 <li><tt>sle</tt>: signed less or equal</li>
5019</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5020
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5021<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5022 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5023 typed. They must also be identical types.</p>
5024
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5025<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5026<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5027 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5028 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]5029 result, as follows:</p>
5030
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5031<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5032 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5033 <tt>false</tt> otherwise. No sign interpretation is necessary or
5034 performed.</li>
5035
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5036 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037 <tt>false</tt> otherwise. No sign interpretation is necessary or
5038 performed.</li>
5039
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5042
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5043 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5045 to <tt>op2</tt>.</li>
5046
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5047 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5049
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5050 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5052
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5053 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5054 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5055
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5056 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5057 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5058 to <tt>op2</tt>.</li>
5059
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5060 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5062
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5063 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5064 <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]5065</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5067<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068 values are compared as if they were integers.</p>
5069
5070<p>If the operands are integer vectors, then they are compared element by
5071 element. The result is an <tt>i1</tt> vector with the same number of elements
5072 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073
5074<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075<pre>
5076 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5077 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5078 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5079 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5080 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5081 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5082</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5083
5084<p>Note that the code generator does not yet support vector types with
5085 the <tt>icmp</tt> instruction.</p>
5086
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5087</div>
5088
5089<!-- _______________________________________________________________________ -->
5090<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5091</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5092
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5093<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5094
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5095<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5096<pre>
5097 &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]5098</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5099
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5102 values based on comparison of its operands.</p>
5103
5104<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]5105(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106
5107<p>If the operands are floating point vectors, then the result type is a vector
5108 of boolean with the same number of elements as the operands being
5109 compared.</p>
5110
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5111<h5>Arguments:</h5>
5112<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113 the condition code indicating the kind of comparison to perform. It is not a
5114 value, just a keyword. The possible condition code are:</p>
5115
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5116<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5117 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5118 <li><tt>oeq</tt>: ordered and equal</li>
5119 <li><tt>ogt</tt>: ordered and greater than </li>
5120 <li><tt>oge</tt>: ordered and greater than or equal</li>
5121 <li><tt>olt</tt>: ordered and less than </li>
5122 <li><tt>ole</tt>: ordered and less than or equal</li>
5123 <li><tt>one</tt>: ordered and not equal</li>
5124 <li><tt>ord</tt>: ordered (no nans)</li>
5125 <li><tt>ueq</tt>: unordered or equal</li>
5126 <li><tt>ugt</tt>: unordered or greater than </li>
5127 <li><tt>uge</tt>: unordered or greater than or equal</li>
5128 <li><tt>ult</tt>: unordered or less than </li>
5129 <li><tt>ule</tt>: unordered or less than or equal</li>
5130 <li><tt>une</tt>: unordered or not equal</li>
5131 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5132 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5135<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136 <i>unordered</i> means that either operand may be a QNAN.</p>
5137
5138<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5139 a <a href="#t_floating">floating point</a> type or
5140 a <a href="#t_vector">vector</a> of floating point type. They must have
5141 identical types.</p>
5142
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5143<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5144<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5145 according to the condition code given as <tt>cond</tt>. If the operands are
5146 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5147 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5148 follows:</p>
5149
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5150<ol>
5151 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5153 <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]5154 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5155
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5156 <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]5157 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5162 <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]5163 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5164
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5165 <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]5166 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5167
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5168 <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]5169 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5170
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5171 <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]5172
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5175
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5176 <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]5177 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5178
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5179 <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]5180 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5181
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5182 <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]5183 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5184
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5185 <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]5186 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5187
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5188 <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]5189 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5190
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5191 <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]5192
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5193 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5194</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5195
5196<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5197<pre>
5198 &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]5199 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5200 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5201 &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]5202</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5203
5204<p>Note that the code generator does not yet support vector types with
5205 the <tt>fcmp</tt> instruction.</p>
5206
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5207</div>
5208
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5209<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5210<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5211 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5212</div>
5213
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5214<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5215
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5216<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217<pre>
5218 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5219</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5220
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5221<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5222<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5223 SSA graph representing the function.</p>
5224
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5225<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5226<p>The type of the incoming values is specified with the first type field. After
5227 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5228 one pair for each predecessor basic block of the current block. Only values
5229 of <a href="#t_firstclass">first class</a> type may be used as the value
5230 arguments to the PHI node. Only labels may be used as the label
5231 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5232
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5233<p>There must be no non-phi instructions between the start of a basic block and
5234 the PHI instructions: i.e. PHI instructions must be first in a basic
5235 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5236
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5237<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5238 occur on the edge from the corresponding predecessor block to the current
5239 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5240 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5241
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5242<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5243<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5244 specified by the pair corresponding to the predecessor basic block that
5245 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5246
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5247<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5248<pre>
5249Loop: ; Infinite loop that counts from 0 on up...
5250 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5251 %nextindvar = add i32 %indvar, 1
5252 br label %Loop
5253</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5254
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5255</div>
5256
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5257<!-- _______________________________________________________________________ -->
5258<div class="doc_subsubsection">
5259 <a name="i_select">'<tt>select</tt>' Instruction</a>
5260</div>
5261
5262<div class="doc_text">
5263
5264<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5265<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5266 &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>
5267
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5268 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5269</pre>
5270
5271<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5272<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5273 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5274
5275
5276<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5278 values indicating the condition, and two values of the
5279 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5280 vectors and the condition is a scalar, then entire vectors are selected, not
5281 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5282
5283<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5284<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5285 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5286
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5287<p>If the condition is a vector of i1, then the value arguments must be vectors
5288 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5289
5290<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5291<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5292 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5293</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5294
5295<p>Note that the code generator does not yet support conditions
5296 with vector type.</p>
5297
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5298</div>
5299
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5300<!-- _______________________________________________________________________ -->
5301<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5302 <a name="i_call">'<tt>call</tt>' Instruction</a>
5303</div>
5304
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5305<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5307<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5308<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5309 &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]5310</pre>
5311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5312<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5313<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5315<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5316<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5317
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5318<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5319 <li>The optional "tail" marker indicates that the callee function does not
5320 access any allocas or varargs in the caller. Note that calls may be
5321 marked "tail" even if they do not occur before
5322 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5323 present, the function call is eligible for tail call optimization,
5324 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5325 optimized into a jump</a>. The code generator may optimize calls marked
5326 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5327 sibling call optimization</a> when the caller and callee have
5328 matching signatures, or 2) forced tail call optimization when the
5329 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5330 <ul>
5331 <li>Caller and callee both have the calling
5332 convention <tt>fastcc</tt>.</li>
5333 <li>The call is in tail position (ret immediately follows call and ret
5334 uses value of call or is void).</li>
5335 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5336 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5337 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5338 constraints are met.</a></li>
5339 </ul>
5340 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5342 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5343 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5344 defaults to using C calling conventions. The calling convention of the
5345 call must match the calling convention of the target function, or else the
5346 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5347
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5348 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5349 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5350 '<tt>inreg</tt>' attributes are valid here.</li>
5351
5352 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5353 type of the return value. Functions that return no value are marked
5354 <tt><a href="#t_void">void</a></tt>.</li>
5355
5356 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5357 being invoked. The argument types must match the types implied by this
5358 signature. This type can be omitted if the function is not varargs and if
5359 the function type does not return a pointer to a function.</li>
5360
5361 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5362 be invoked. In most cases, this is a direct function invocation, but
5363 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5364 to function value.</li>
5365
5366 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5367 signature argument types and parameter attributes. All arguments must be
5368 of <a href="#t_firstclass">first class</a> type. If the function
5369 signature indicates the function accepts a variable number of arguments,
5370 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5371
5372 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5373 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5374 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5375</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5377<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5378<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5379 a specified function, with its incoming arguments bound to the specified
5380 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5381 function, control flow continues with the instruction after the function
5382 call, and the return value of the function is bound to the result
5383 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5385<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5386<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5387 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5388 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5389 %X = tail call i32 @foo() <i>; yields i32</i>
5390 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5391 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5392
5393 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5394 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5395 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5396 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5397 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5398 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5399</pre>
5400
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5401<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5402standard C99 library as being the C99 library functions, and may perform
5403optimizations or generate code for them under that assumption. This is
5404something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5405freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5406
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5407</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5408
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5409<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5410<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5411 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5412</div>
5413
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5414<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5415
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5416<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5417<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5418 &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]5419</pre>
5420
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5421<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5422<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5423 the "variable argument" area of a function call. It is used to implement the
5424 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5425
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5427<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5428 argument. It returns a value of the specified argument type and increments
5429 the <tt>va_list</tt> to point to the next argument. The actual type
5430 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5431
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5432<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5433<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5434 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5435 to the next argument. For more information, see the variable argument
5436 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5437
5438<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]5439 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5440 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5441
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442<p><tt>va_arg</tt> is an LLVM instruction instead of
5443 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5444 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5445
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5446<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5447<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5448
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5449<p>Note that the code generator does not yet fully support va_arg on many
5450 targets. Also, it does not currently support va_arg with aggregate types on
5451 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5453</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5454
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5455<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5456<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5457<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5458
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5459<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5460
5461<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5462 well known names and semantics and are required to follow certain
5463 restrictions. Overall, these intrinsics represent an extension mechanism for
5464 the LLVM language that does not require changing all of the transformations
5465 in LLVM when adding to the language (or the bitcode reader/writer, the
5466 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5467
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5468<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5469 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5470 begin with this prefix. Intrinsic functions must always be external
5471 functions: you cannot define the body of intrinsic functions. Intrinsic
5472 functions may only be used in call or invoke instructions: it is illegal to
5473 take the address of an intrinsic function. Additionally, because intrinsic
5474 functions are part of the LLVM language, it is required if any are added that
5475 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5477<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5478 family of functions that perform the same operation but on different data
5479 types. Because LLVM can represent over 8 million different integer types,
5480 overloading is used commonly to allow an intrinsic function to operate on any
5481 integer type. One or more of the argument types or the result type can be
5482 overloaded to accept any integer type. Argument types may also be defined as
5483 exactly matching a previous argument's type or the result type. This allows
5484 an intrinsic function which accepts multiple arguments, but needs all of them
5485 to be of the same type, to only be overloaded with respect to a single
5486 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5487
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5488<p>Overloaded intrinsics will have the names of its overloaded argument types
5489 encoded into its function name, each preceded by a period. Only those types
5490 which are overloaded result in a name suffix. Arguments whose type is matched
5491 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5492 can take an integer of any width and returns an integer of exactly the same
5493 integer width. This leads to a family of functions such as
5494 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5495 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5496 suffix is required. Because the argument's type is matched against the return
5497 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5498
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5499<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5501
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5502</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5503
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5504<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5505<div class="doc_subsection">
5506 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5507</div>
5508
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5509<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5511<p>Variable argument support is defined in LLVM with
5512 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5513 intrinsic functions. These functions are related to the similarly named
5514 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5516<p>All of these functions operate on arguments that use a target-specific value
5517 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5518 not define what this type is, so all transformations should be prepared to
5519 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5520
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5521<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]5522 instruction and the variable argument handling intrinsic functions are
5523 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5524
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5525<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5526define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5527 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5528 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5529 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5530 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5531
5532 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5533 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5534
5535 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5536 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5537 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5538 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5539 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5540
5541 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5542 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5543 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5544}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5545
5546declare void @llvm.va_start(i8*)
5547declare void @llvm.va_copy(i8*, i8*)
5548declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5549</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5550
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5551</div>
5552
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5553<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5554<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5555 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5556</div>
5557
5558
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5559<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5560
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5561<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562<pre>
5563 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5564</pre>
5565
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5566<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5568 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]5569
5570<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5571<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]5572
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5573<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5574<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]5575 macro available in C. In a target-dependent way, it initializes
5576 the <tt>va_list</tt> element to which the argument points, so that the next
5577 call to <tt>va_arg</tt> will produce the first variable argument passed to
5578 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5579 need to know the last argument of the function as the compiler can figure
5580 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5582</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5583
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5584<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5585<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5586 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5587</div>
5588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5589<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5590
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591<h5>Syntax:</h5>
5592<pre>
5593 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5594</pre>
5595
5596<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5597<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5598 which has been initialized previously
5599 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5600 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5601
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5602<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5603<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]5604
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5605<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5606<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]5607 macro available in C. In a target-dependent way, it destroys
5608 the <tt>va_list</tt> element to which the argument points. Calls
5609 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5610 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5611 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5613</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5616<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5617 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5618</div>
5619
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5620<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5621
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5622<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5623<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5624 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5625</pre>
5626
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5628<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5630
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5631<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5632<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]5633 The second argument is a pointer to a <tt>va_list</tt> element to copy
5634 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5635
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5636<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5637<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]5638 macro available in C. In a target-dependent way, it copies the
5639 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5640 element. This intrinsic is necessary because
5641 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5642 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5644</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5645
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5646<!-- ======================================================================= -->
5647<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5648 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5649</div>
5650
5651<div class="doc_text">
5652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5653<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5654Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5655intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5656roots on the stack</a>, as well as garbage collector implementations that
5657require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5658barriers. Front-ends for type-safe garbage collected languages should generate
5659these intrinsics to make use of the LLVM garbage collectors. For more details,
5660see <a href="GarbageCollection.html">Accurate Garbage Collection with
5661LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663<p>The garbage collection intrinsics only operate on objects in the generic
5664 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5665
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5666</div>
5667
5668<!-- _______________________________________________________________________ -->
5669<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5670 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5671</div>
5672
5673<div class="doc_text">
5674
5675<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5677 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5678</pre>
5679
5680<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5681<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]5682 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5685<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5686 root pointer. The second pointer (which must be either a constant or a
5687 global value address) contains the meta-data to be associated with the
5688 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689
5690<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5691<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]5692 location. At compile-time, the code generator generates information to allow
5693 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5694 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5695 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5696
5697</div>
5698
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5699<!-- _______________________________________________________________________ -->
5700<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5701 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5702</div>
5703
5704<div class="doc_text">
5705
5706<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5708 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5709</pre>
5710
5711<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5713 locations, allowing garbage collector implementations that require read
5714 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715
5716<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5717<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]5718 allocated from the garbage collector. The first object is a pointer to the
5719 start of the referenced object, if needed by the language runtime (otherwise
5720 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5721
5722<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724 instruction, but may be replaced with substantially more complex code by the
5725 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5726 may only be used in a function which <a href="#gc">specifies a GC
5727 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5728
5729</div>
5730
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731<!-- _______________________________________________________________________ -->
5732<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5733 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5734</div>
5735
5736<div class="doc_text">
5737
5738<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5740 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5741</pre>
5742
5743<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745 locations, allowing garbage collector implementations that require write
5746 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5747
5748<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5749<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]5750 object to store it to, and the third is the address of the field of Obj to
5751 store to. If the runtime does not require a pointer to the object, Obj may
5752 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5753
5754<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5756 instruction, but may be replaced with substantially more complex code by the
5757 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5758 may only be used in a function which <a href="#gc">specifies a GC
5759 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5760
5761</div>
5762
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5763<!-- ======================================================================= -->
5764<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5765 <a name="int_codegen">Code Generator Intrinsics</a>
5766</div>
5767
5768<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5769
5770<p>These intrinsics are provided by LLVM to expose special features that may
5771 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5772
5773</div>
5774
5775<!-- _______________________________________________________________________ -->
5776<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5777 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778</div>
5779
5780<div class="doc_text">
5781
5782<h5>Syntax:</h5>
5783<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5784 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5785</pre>
5786
5787<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5788<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5789 target-specific value indicating the return address of the current function
5790 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5791
5792<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5793<p>The argument to this intrinsic indicates which function to return the address
5794 for. Zero indicates the calling function, one indicates its caller, etc.
5795 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796
5797<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5799 indicating the return address of the specified call frame, or zero if it
5800 cannot be identified. The value returned by this intrinsic is likely to be
5801 incorrect or 0 for arguments other than zero, so it should only be used for
5802 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5803
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804<p>Note that calling this intrinsic does not prevent function inlining or other
5805 aggressive transformations, so the value returned may not be that of the
5806 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5807
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5808</div>
5809
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5810<!-- _______________________________________________________________________ -->
5811<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5812 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813</div>
5814
5815<div class="doc_text">
5816
5817<h5>Syntax:</h5>
5818<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5819 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820</pre>
5821
5822<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5823<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5824 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5825
5826<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827<p>The argument to this intrinsic indicates which function to return the frame
5828 pointer for. Zero indicates the calling function, one indicates its caller,
5829 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5830
5831<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5832<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5833 indicating the frame address of the specified call frame, or zero if it
5834 cannot be identified. The value returned by this intrinsic is likely to be
5835 incorrect or 0 for arguments other than zero, so it should only be used for
5836 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5838<p>Note that calling this intrinsic does not prevent function inlining or other
5839 aggressive transformations, so the value returned may not be that of the
5840 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5841
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5842</div>
5843
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5844<!-- _______________________________________________________________________ -->
5845<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5846 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5847</div>
5848
5849<div class="doc_text">
5850
5851<h5>Syntax:</h5>
5852<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5853 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5854</pre>
5855
5856<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5858 of the function stack, for use
5859 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5860 useful for implementing language features like scoped automatic variable
5861 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5862
5863<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5864<p>This intrinsic returns a opaque pointer value that can be passed
5865 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5866 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5867 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5868 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5869 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5870 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5871
5872</div>
5873
5874<!-- _______________________________________________________________________ -->
5875<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5876 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5877</div>
5878
5879<div class="doc_text">
5880
5881<h5>Syntax:</h5>
5882<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5883 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5884</pre>
5885
5886<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5887<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5888 the function stack to the state it was in when the
5889 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5890 executed. This is useful for implementing language features like scoped
5891 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5892
5893<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5894<p>See the description
5895 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5896
5897</div>
5898
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5901 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
5907<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5908 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]5909</pre>
5910
5911<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5912<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5913 insert a prefetch instruction if supported; otherwise, it is a noop.
5914 Prefetches have no effect on the behavior of the program but can change its
5915 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5916
5917<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5918<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5919 specifier determining if the fetch should be for a read (0) or write (1),
5920 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5921 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5922 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5923
5924<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5925<p>This intrinsic does not modify the behavior of the program. In particular,
5926 prefetches cannot trap and do not produce a value. On targets that support
5927 this intrinsic, the prefetch can provide hints to the processor cache for
5928 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5929
5930</div>
5931
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5932<!-- _______________________________________________________________________ -->
5933<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5934 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5935</div>
5936
5937<div class="doc_text">
5938
5939<h5>Syntax:</h5>
5940<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5941 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5942</pre>
5943
5944<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5945<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5946 Counter (PC) in a region of code to simulators and other tools. The method
5947 is target specific, but it is expected that the marker will use exported
5948 symbols to transmit the PC of the marker. The marker makes no guarantees
5949 that it will remain with any specific instruction after optimizations. It is
5950 possible that the presence of a marker will inhibit optimizations. The
5951 intended use is to be inserted after optimizations to allow correlations of
5952 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5953
5954<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5956
5957<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5959 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5960
5961</div>
5962
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5963<!-- _______________________________________________________________________ -->
5964<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5965 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5966</div>
5967
5968<div class="doc_text">
5969
5970<h5>Syntax:</h5>
5971<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5972 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5973</pre>
5974
5975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5977 counter register (or similar low latency, high accuracy clocks) on those
5978 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5979 should map to RPCC. As the backing counters overflow quickly (on the order
5980 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5981
5982<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5983<p>When directly supported, reading the cycle counter should not modify any
5984 memory. Implementations are allowed to either return a application specific
5985 value or a system wide value. On backends without support, this is lowered
5986 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5987
5988</div>
5989
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5990<!-- ======================================================================= -->
5991<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5992 <a name="int_libc">Standard C Library Intrinsics</a>
5993</div>
5994
5995<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5996
5997<p>LLVM provides intrinsics for a few important standard C library functions.
5998 These intrinsics allow source-language front-ends to pass information about
5999 the alignment of the pointer arguments to the code generator, providing
6000 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6001
6002</div>
6003
6004<!-- _______________________________________________________________________ -->
6005<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6006 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6007</div>
6008
6009<div class="doc_text">
6010
6011<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012<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]6013 integer bit width and for different address spaces. Not all targets support
6014 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6015
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6016<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6017 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]6018 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6019 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]6020 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6021</pre>
6022
6023<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6025 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6027<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6028 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6029 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6030
6031<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6032
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6033<p>The first argument is a pointer to the destination, the second is a pointer
6034 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6035 number of bytes to copy, the fourth argument is the alignment of the
6036 source and destination locations, and the fifth is a boolean indicating a
6037 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6038
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6039<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]6040 then the caller guarantees that both the source and destination pointers are
6041 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6042
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6043<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6044 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6045 The detailed access behavior is not very cleanly specified and it is unwise
6046 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6047
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6048<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6049
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6051 source location to the destination location, which are not allowed to
6052 overlap. It copies "len" bytes of memory over. If the argument is known to
6053 be aligned to some boundary, this can be specified as the fourth argument,
6054 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6055
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6056</div>
6057
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6058<!-- _______________________________________________________________________ -->
6059<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6060 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6061</div>
6062
6063<div class="doc_text">
6064
6065<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6066<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]6067 width and for different address space. Not all targets support all bit
6068 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6069
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6070<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6071 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]6072 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6073 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]6074 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6075</pre>
6076
6077<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6079 source location to the destination location. It is similar to the
6080 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6081 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6083<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6084 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6085 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6086
6087<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089<p>The first argument is a pointer to the destination, the second is a pointer
6090 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6091 number of bytes to copy, the fourth argument is the alignment of the
6092 source and destination locations, and the fifth is a boolean indicating a
6093 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6094
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6095<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]6096 then the caller guarantees that the source and destination pointers are
6097 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6098
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6099<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6100 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6101 The detailed access behavior is not very cleanly specified and it is unwise
6102 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6103
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6104<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6105
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6107 source location to the destination location, which may overlap. It copies
6108 "len" bytes of memory over. If the argument is known to be aligned to some
6109 boundary, this can be specified as the fourth argument, otherwise it should
6110 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6111
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6112</div>
6113
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6114<!-- _______________________________________________________________________ -->
6115<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6116 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6117</div>
6118
6119<div class="doc_text">
6120
6121<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6122<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6123 width and for different address spaces. However, not all targets support all
6124 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6125
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6126<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6127 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6128 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6129 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6130 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6131</pre>
6132
6133<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6134<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6135 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6138 intrinsic does not return a value and takes extra alignment/volatile
6139 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6140
6141<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6142<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6143 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6144 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6145 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6146
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6147<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]6148 then the caller guarantees that the destination pointer is aligned to that
6149 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6150
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6151<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6152 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6153 The detailed access behavior is not very cleanly specified and it is unwise
6154 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6155
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6156<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6157<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6158 at the destination location. If the argument is known to be aligned to some
6159 boundary, this can be specified as the fourth argument, otherwise it should
6160 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6161
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6162</div>
6163
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6164<!-- _______________________________________________________________________ -->
6165<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6166 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6167</div>
6168
6169<div class="doc_text">
6170
6171<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6172<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6173 floating point or vector of floating point type. Not all targets support all
6174 types however.</p>
6175
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6176<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6177 declare float @llvm.sqrt.f32(float %Val)
6178 declare double @llvm.sqrt.f64(double %Val)
6179 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6180 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6181 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6182</pre>
6183
6184<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6185<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6186 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6187 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6188 behavior for negative numbers other than -0.0 (which allows for better
6189 optimization, because there is no need to worry about errno being
6190 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]6191
6192<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6193<p>The argument and return value are floating point numbers of the same
6194 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6195
6196<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6197<p>This function returns the sqrt of the specified operand if it is a
6198 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6199
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6200</div>
6201
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6202<!-- _______________________________________________________________________ -->
6203<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6204 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6205</div>
6206
6207<div class="doc_text">
6208
6209<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6211 floating point or vector of floating point type. Not all targets support all
6212 types however.</p>
6213
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6214<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6215 declare float @llvm.powi.f32(float %Val, i32 %power)
6216 declare double @llvm.powi.f64(double %Val, i32 %power)
6217 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6218 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6219 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6220</pre>
6221
6222<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6223<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6224 specified (positive or negative) power. The order of evaluation of
6225 multiplications is not defined. When a vector of floating point type is
6226 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6227
6228<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6229<p>The second argument is an integer power, and the first is a value to raise to
6230 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6231
6232<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6233<p>This function returns the first value raised to the second power with an
6234 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6235
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6236</div>
6237
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6238<!-- _______________________________________________________________________ -->
6239<div class="doc_subsubsection">
6240 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6241</div>
6242
6243<div class="doc_text">
6244
6245<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6246<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6247 floating point or vector of floating point type. Not all targets support all
6248 types however.</p>
6249
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6250<pre>
6251 declare float @llvm.sin.f32(float %Val)
6252 declare double @llvm.sin.f64(double %Val)
6253 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6254 declare fp128 @llvm.sin.f128(fp128 %Val)
6255 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6256</pre>
6257
6258<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6259<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6260
6261<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6262<p>The argument and return value are floating point numbers of the same
6263 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6264
6265<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6266<p>This function returns the sine of the specified operand, returning the same
6267 values as the libm <tt>sin</tt> functions would, and handles error conditions
6268 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6269
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6270</div>
6271
6272<!-- _______________________________________________________________________ -->
6273<div class="doc_subsubsection">
6274 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6275</div>
6276
6277<div class="doc_text">
6278
6279<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6280<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6281 floating point or vector of floating point type. Not all targets support all
6282 types however.</p>
6283
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6284<pre>
6285 declare float @llvm.cos.f32(float %Val)
6286 declare double @llvm.cos.f64(double %Val)
6287 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6288 declare fp128 @llvm.cos.f128(fp128 %Val)
6289 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6290</pre>
6291
6292<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6293<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6294
6295<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6296<p>The argument and return value are floating point numbers of the same
6297 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6298
6299<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6300<p>This function returns the cosine of the specified operand, returning the same
6301 values as the libm <tt>cos</tt> functions would, and handles error conditions
6302 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6303
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6304</div>
6305
6306<!-- _______________________________________________________________________ -->
6307<div class="doc_subsubsection">
6308 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6309</div>
6310
6311<div class="doc_text">
6312
6313<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6314<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6315 floating point or vector of floating point type. Not all targets support all
6316 types however.</p>
6317
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6318<pre>
6319 declare float @llvm.pow.f32(float %Val, float %Power)
6320 declare double @llvm.pow.f64(double %Val, double %Power)
6321 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6322 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6323 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6324</pre>
6325
6326<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6327<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6328 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6329
6330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6331<p>The second argument is a floating point power, and the first is a value to
6332 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6333
6334<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6335<p>This function returns the first value raised to the second power, returning
6336 the same values as the libm <tt>pow</tt> functions would, and handles error
6337 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6338
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6339</div>
6340
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6341<!-- ======================================================================= -->
6342<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6343 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6344</div>
6345
6346<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347
6348<p>LLVM provides intrinsics for a few important bit manipulation operations.
6349 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6350
6351</div>
6352
6353<!-- _______________________________________________________________________ -->
6354<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6355 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6356</div>
6357
6358<div class="doc_text">
6359
6360<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6361<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6362 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6363
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6364<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6365 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6366 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6367 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6368</pre>
6369
6370<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6371<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6372 values with an even number of bytes (positive multiple of 16 bits). These
6373 are useful for performing operations on data that is not in the target's
6374 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6375
6376<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6377<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6378 and low byte of the input i16 swapped. Similarly,
6379 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6380 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6381 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6382 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6383 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6384 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6385
6386</div>
6387
6388<!-- _______________________________________________________________________ -->
6389<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6390 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6391</div>
6392
6393<div class="doc_text">
6394
6395<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6396<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]6397 width. Not all targets support all bit widths however.</p>
6398
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6399<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6400 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6401 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6402 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6403 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6404 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6405</pre>
6406
6407<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6409 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6410
6411<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6412<p>The only argument is the value to be counted. The argument may be of any
6413 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6414
6415<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<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]6417
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6418</div>
6419
6420<!-- _______________________________________________________________________ -->
6421<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6422 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6423</div>
6424
6425<div class="doc_text">
6426
6427<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6429 integer bit width. Not all targets support all bit widths however.</p>
6430
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6431<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6432 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6433 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6434 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6435 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6436 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6437</pre>
6438
6439<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6440<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6441 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6442
6443<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6444<p>The only argument is the value to be counted. The argument may be of any
6445 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6446
6447<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6448<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6449 zeros in a variable. If the src == 0 then the result is the size in bits of
6450 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6451
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6452</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6453
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6454<!-- _______________________________________________________________________ -->
6455<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6456 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6457</div>
6458
6459<div class="doc_text">
6460
6461<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6463 integer bit width. Not all targets support all bit widths however.</p>
6464
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6465<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6466 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6467 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6468 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6469 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6470 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6471</pre>
6472
6473<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6474<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6475 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6476
6477<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6478<p>The only argument is the value to be counted. The argument may be of any
6479 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6480
6481<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6483 zeros in a variable. If the src == 0 then the result is the size in bits of
6484 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6485
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6486</div>
6487
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6488<!-- ======================================================================= -->
6489<div class="doc_subsection">
6490 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6491</div>
6492
6493<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494
6495<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6496
6497</div>
6498
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6499<!-- _______________________________________________________________________ -->
6500<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6501 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6502</div>
6503
6504<div class="doc_text">
6505
6506<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6507<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]6508 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6509
6510<pre>
6511 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6512 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6513 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6514</pre>
6515
6516<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6517<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6518 a signed addition of the two arguments, and indicate whether an overflow
6519 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6520
6521<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6522<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]6523 be of integer types of any bit width, but they must have the same bit
6524 width. The second element of the result structure must be of
6525 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6526 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527
6528<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6529<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6530 a signed addition of the two variables. They return a structure &mdash; the
6531 first element of which is the signed summation, and the second element of
6532 which is a bit specifying if the signed summation resulted in an
6533 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6534
6535<h5>Examples:</h5>
6536<pre>
6537 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6538 %sum = extractvalue {i32, i1} %res, 0
6539 %obit = extractvalue {i32, i1} %res, 1
6540 br i1 %obit, label %overflow, label %normal
6541</pre>
6542
6543</div>
6544
6545<!-- _______________________________________________________________________ -->
6546<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6547 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6548</div>
6549
6550<div class="doc_text">
6551
6552<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553<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]6554 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6555
6556<pre>
6557 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6558 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6559 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6560</pre>
6561
6562<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6563<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6564 an unsigned addition of the two arguments, and indicate whether a carry
6565 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6566
6567<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6568<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]6569 be of integer types of any bit width, but they must have the same bit
6570 width. The second element of the result structure must be of
6571 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6572 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573
6574<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6575<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576 an unsigned addition of the two arguments. They return a structure &mdash;
6577 the first element of which is the sum, and the second element of which is a
6578 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6579
6580<h5>Examples:</h5>
6581<pre>
6582 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6583 %sum = extractvalue {i32, i1} %res, 0
6584 %obit = extractvalue {i32, i1} %res, 1
6585 br i1 %obit, label %carry, label %normal
6586</pre>
6587
6588</div>
6589
6590<!-- _______________________________________________________________________ -->
6591<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6592 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6593</div>
6594
6595<div class="doc_text">
6596
6597<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6598<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]6599 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6600
6601<pre>
6602 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6603 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6604 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6605</pre>
6606
6607<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6608<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6609 a signed subtraction of the two arguments, and indicate whether an overflow
6610 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6611
6612<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6613<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]6614 be of integer types of any bit width, but they must have the same bit
6615 width. The second element of the result structure must be of
6616 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6617 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618
6619<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6620<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6621 a signed subtraction of the two arguments. They return a structure &mdash;
6622 the first element of which is the subtraction, and the second element of
6623 which is a bit specifying if the signed subtraction resulted in an
6624 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6625
6626<h5>Examples:</h5>
6627<pre>
6628 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6629 %sum = extractvalue {i32, i1} %res, 0
6630 %obit = extractvalue {i32, i1} %res, 1
6631 br i1 %obit, label %overflow, label %normal
6632</pre>
6633
6634</div>
6635
6636<!-- _______________________________________________________________________ -->
6637<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6638 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6639</div>
6640
6641<div class="doc_text">
6642
6643<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6644<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]6645 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6646
6647<pre>
6648 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6649 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6650 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6651</pre>
6652
6653<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6654<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6655 an unsigned subtraction of the two arguments, and indicate whether an
6656 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6657
6658<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659<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]6660 be of integer types of any bit width, but they must have the same bit
6661 width. The second element of the result structure must be of
6662 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6663 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664
6665<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6667 an unsigned subtraction of the two arguments. They return a structure &mdash;
6668 the first element of which is the subtraction, and the second element of
6669 which is a bit specifying if the unsigned subtraction resulted in an
6670 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671
6672<h5>Examples:</h5>
6673<pre>
6674 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6675 %sum = extractvalue {i32, i1} %res, 0
6676 %obit = extractvalue {i32, i1} %res, 1
6677 br i1 %obit, label %overflow, label %normal
6678</pre>
6679
6680</div>
6681
6682<!-- _______________________________________________________________________ -->
6683<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6684 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6685</div>
6686
6687<div class="doc_text">
6688
6689<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690<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]6691 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<pre>
6694 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6695 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6696 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6697</pre>
6698
6699<h5>Overview:</h5>
6700
6701<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6702 a signed multiplication of the two arguments, and indicate whether an
6703 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6704
6705<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6706<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]6707 be of integer types of any bit width, but they must have the same bit
6708 width. The second element of the result structure must be of
6709 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6710 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6711
6712<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6713<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6714 a signed multiplication of the two arguments. They return a structure &mdash;
6715 the first element of which is the multiplication, and the second element of
6716 which is a bit specifying if the signed multiplication resulted in an
6717 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6718
6719<h5>Examples:</h5>
6720<pre>
6721 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6722 %sum = extractvalue {i32, i1} %res, 0
6723 %obit = extractvalue {i32, i1} %res, 1
6724 br i1 %obit, label %overflow, label %normal
6725</pre>
6726
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6727</div>
6728
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6729<!-- _______________________________________________________________________ -->
6730<div class="doc_subsubsection">
6731 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6732</div>
6733
6734<div class="doc_text">
6735
6736<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6737<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]6738 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6739
6740<pre>
6741 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6742 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6743 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6744</pre>
6745
6746<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6747<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748 a unsigned multiplication of the two arguments, and indicate whether an
6749 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6750
6751<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6752<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]6753 be of integer types of any bit width, but they must have the same bit
6754 width. The second element of the result structure must be of
6755 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6756 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6757
6758<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6759<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6760 an unsigned multiplication of the two arguments. They return a structure
6761 &mdash; the first element of which is the multiplication, and the second
6762 element of which is a bit specifying if the unsigned multiplication resulted
6763 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6764
6765<h5>Examples:</h5>
6766<pre>
6767 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6768 %sum = extractvalue {i32, i1} %res, 0
6769 %obit = extractvalue {i32, i1} %res, 1
6770 br i1 %obit, label %overflow, label %normal
6771</pre>
6772
6773</div>
6774
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6775<!-- ======================================================================= -->
6776<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6777 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6778</div>
6779
6780<div class="doc_text">
6781
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6782<p>Half precision floating point is a storage-only format. This means that it is
6783 a dense encoding (in memory) but does not support computation in the
6784 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6785
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6786<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6787 value as an i16, then convert it to float with <a
6788 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6789 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6790 double etc). To store the value back to memory, it is first converted to
6791 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6792 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6793 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6794</div>
6795
6796<!-- _______________________________________________________________________ -->
6797<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6798 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6799</div>
6800
6801<div class="doc_text">
6802
6803<h5>Syntax:</h5>
6804<pre>
6805 declare i16 @llvm.convert.to.fp16(f32 %a)
6806</pre>
6807
6808<h5>Overview:</h5>
6809<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6810 a conversion from single precision floating point format to half precision
6811 floating point format.</p>
6812
6813<h5>Arguments:</h5>
6814<p>The intrinsic function contains single argument - the value to be
6815 converted.</p>
6816
6817<h5>Semantics:</h5>
6818<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6819 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6820 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6821 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6822
6823<h5>Examples:</h5>
6824<pre>
6825 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6826 store i16 %res, i16* @x, align 2
6827</pre>
6828
6829</div>
6830
6831<!-- _______________________________________________________________________ -->
6832<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6833 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6834</div>
6835
6836<div class="doc_text">
6837
6838<h5>Syntax:</h5>
6839<pre>
6840 declare f32 @llvm.convert.from.fp16(i16 %a)
6841</pre>
6842
6843<h5>Overview:</h5>
6844<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6845 a conversion from half precision floating point format to single precision
6846 floating point format.</p>
6847
6848<h5>Arguments:</h5>
6849<p>The intrinsic function contains single argument - the value to be
6850 converted.</p>
6851
6852<h5>Semantics:</h5>
6853<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6854 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6855 precision floating point format. The input half-float value is represented by
6856 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6857
6858<h5>Examples:</h5>
6859<pre>
6860 %a = load i16* @x, align 2
6861 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6862</pre>
6863
6864</div>
6865
6866<!-- ======================================================================= -->
6867<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6868 <a name="int_debugger">Debugger Intrinsics</a>
6869</div>
6870
6871<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6872
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6873<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6874 prefix), are described in
6875 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6876 Level Debugging</a> document.</p>
6877
6878</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6879
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6880<!-- ======================================================================= -->
6881<div class="doc_subsection">
6882 <a name="int_eh">Exception Handling Intrinsics</a>
6883</div>
6884
6885<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886
6887<p>The LLVM exception handling intrinsics (which all start with
6888 <tt>llvm.eh.</tt> prefix), are described in
6889 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6890 Handling</a> document.</p>
6891
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6892</div>
6893
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6894<!-- ======================================================================= -->
6895<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6896 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6897</div>
6898
6899<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6900
6901<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6902 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6903 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6904 function pointer lacking the nest parameter - the caller does not need to
6905 provide a value for it. Instead, the value to use is stored in advance in a
6906 "trampoline", a block of memory usually allocated on the stack, which also
6907 contains code to splice the nest value into the argument list. This is used
6908 to implement the GCC nested function address extension.</p>
6909
6910<p>For example, if the function is
6911 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6912 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6913 follows:</p>
6914
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6915<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6916 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6917 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6918 %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]6919 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6920</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6921
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6922<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6923 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6925</div>
6926
6927<!-- _______________________________________________________________________ -->
6928<div class="doc_subsubsection">
6929 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6930</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6931
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6932<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6933
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6934<h5>Syntax:</h5>
6935<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6936 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]6937</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6939<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6941 function pointer suitable for executing it.</p>
6942
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6943<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6944<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6945 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6946 sufficiently aligned block of memory; this memory is written to by the
6947 intrinsic. Note that the size and the alignment are target-specific - LLVM
6948 currently provides no portable way of determining them, so a front-end that
6949 generates this intrinsic needs to have some target-specific knowledge.
6950 The <tt>func</tt> argument must hold a function bitcast to
6951 an <tt>i8*</tt>.</p>
6952
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6953<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6955 dependent code, turning it into a function. A pointer to this function is
6956 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6957 function pointer type</a> before being called. The new function's signature
6958 is the same as that of <tt>func</tt> with any arguments marked with
6959 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6960 is allowed, and it must be of pointer type. Calling the new function is
6961 equivalent to calling <tt>func</tt> with the same argument list, but
6962 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6963 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6964 by <tt>tramp</tt> is modified, then the effect of any later call to the
6965 returned function pointer is undefined.</p>
6966
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6967</div>
6968
6969<!-- ======================================================================= -->
6970<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6971 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6972</div>
6973
6974<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6975
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6977 hardware constructs for atomic operations and memory synchronization. This
6978 provides an interface to the hardware, not an interface to the programmer. It
6979 is aimed at a low enough level to allow any programming models or APIs
6980 (Application Programming Interfaces) which need atomic behaviors to map
6981 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6982 hardware provides a "universal IR" for source languages, it also provides a
6983 starting point for developing a "universal" atomic operation and
6984 synchronization IR.</p>
6985
6986<p>These do <em>not</em> form an API such as high-level threading libraries,
6987 software transaction memory systems, atomic primitives, and intrinsic
6988 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6989 application libraries. The hardware interface provided by LLVM should allow
6990 a clean implementation of all of these APIs and parallel programming models.
6991 No one model or paradigm should be selected above others unless the hardware
6992 itself ubiquitously does so.</p>
6993
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6994</div>
6995
6996<!-- _______________________________________________________________________ -->
6997<div class="doc_subsubsection">
6998 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6999</div>
7000<div class="doc_text">
7001<h5>Syntax:</h5>
7002<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7003 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]7004</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7005
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7006<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7007<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7008 specific pairs of memory access types.</p>
7009
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7010<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7012 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7013 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7016<ul>
7017 <li><tt>ll</tt>: load-load barrier</li>
7018 <li><tt>ls</tt>: load-store barrier</li>
7019 <li><tt>sl</tt>: store-load barrier</li>
7020 <li><tt>ss</tt>: store-store barrier</li>
7021 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7022</ul>
7023
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7024<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7025<p>This intrinsic causes the system to enforce some ordering constraints upon
7026 the loads and stores of the program. This barrier does not
7027 indicate <em>when</em> any events will occur, it only enforces
7028 an <em>order</em> in which they occur. For any of the specified pairs of load
7029 and store operations (f.ex. load-load, or store-load), all of the first
7030 operations preceding the barrier will complete before any of the second
7031 operations succeeding the barrier begin. Specifically the semantics for each
7032 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7033
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7034<ul>
7035 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7036 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7037 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7038 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7039 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7041 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7042 load after the barrier begins.</li>
7043</ul>
7044
7045<p>These semantics are applied with a logical "and" behavior when more than one
7046 is enabled in a single memory barrier intrinsic.</p>
7047
7048<p>Backends may implement stronger barriers than those requested when they do
7049 not support as fine grained a barrier as requested. Some architectures do
7050 not need all types of barriers and on such architectures, these become
7051 noops.</p>
7052
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7053<h5>Example:</h5>
7054<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7055%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7056%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7057 store i32 4, %ptr
7058
7059%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7060 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7061 <i>; guarantee the above finishes</i>
7062 store i32 8, %ptr <i>; before this begins</i>
7063</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7064
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7065</div>
7066
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7067<!-- _______________________________________________________________________ -->
7068<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7069 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7070</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7072<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7073
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7074<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7076 any integer bit width and for different address spaces. Not all targets
7077 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7078
7079<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7080 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7081 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7082 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7083 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]7084</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7085
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7086<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7087<p>This loads a value in memory and compares it to a given value. If they are
7088 equal, it stores a new value into the memory.</p>
7089
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7090<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7091<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7092 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7093 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7094 this integer type. While any bit width integer may be used, targets may only
7095 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7096
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7097<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7098<p>This entire intrinsic must be executed atomically. It first loads the value
7099 in memory pointed to by <tt>ptr</tt> and compares it with the
7100 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7101 memory. The loaded value is yielded in all cases. This provides the
7102 equivalent of an atomic compare-and-swap operation within the SSA
7103 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7105<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7106<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7107%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7108%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7109 store i32 4, %ptr
7110
7111%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7112%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7113 <i>; yields {i32}:result1 = 4</i>
7114%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7115%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7116
7117%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7118%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7119 <i>; yields {i32}:result2 = 8</i>
7120%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7121
7122%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7123</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7124
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7125</div>
7126
7127<!-- _______________________________________________________________________ -->
7128<div class="doc_subsubsection">
7129 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7130</div>
7131<div class="doc_text">
7132<h5>Syntax:</h5>
7133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7135 integer bit width. Not all targets support all bit widths however.</p>
7136
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7137<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7138 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7139 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7140 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7141 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]7142</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7143
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7145<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7146 the value from memory. It then stores the value in <tt>val</tt> in the memory
7147 at <tt>ptr</tt>.</p>
7148
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7150<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7151 the <tt>val</tt> argument and the result must be integers of the same bit
7152 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7153 integer type. The targets may only lower integer representations they
7154 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7155
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7156<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7157<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7158 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7159 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7160
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7161<h5>Examples:</h5>
7162<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7163%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7164%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165 store i32 4, %ptr
7166
7167%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7168%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7169 <i>; yields {i32}:result1 = 4</i>
7170%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7171%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7172
7173%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7174%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175 <i>; yields {i32}:result2 = 8</i>
7176
7177%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7178%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7179</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7180
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7181</div>
7182
7183<!-- _______________________________________________________________________ -->
7184<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7185 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186
7187</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7188
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7189<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7192<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7193 any integer bit width. Not all targets support all bit widths however.</p>
7194
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7195<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7196 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7197 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7198 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7199 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]7200</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7202<h5>Overview:</h5>
7203<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7204 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7205
7206<h5>Arguments:</h5>
7207<p>The intrinsic takes two arguments, the first a pointer to an integer value
7208 and the second an integer value. The result is also an integer value. These
7209 integer types can have any bit width, but they must all have the same bit
7210 width. The targets may only lower integer representations they support.</p>
7211
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7212<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7213<p>This intrinsic does a series of operations atomically. It first loads the
7214 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7215 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]7216
7217<h5>Examples:</h5>
7218<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7219%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7220%ptr = bitcast i8* %mallocP to i32*
7221 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7222%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7223 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7224%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7225 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7226%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7227 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7228%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7229</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7231</div>
7232
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7233<!-- _______________________________________________________________________ -->
7234<div class="doc_subsubsection">
7235 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7236
7237</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7238
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7239<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7241<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7242<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7243 any integer bit width and for different address spaces. Not all targets
7244 support all bit widths however.</p>
7245
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7246<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7247 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7248 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7249 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7250 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]7251</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7252
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7254<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7256
7257<h5>Arguments:</h5>
7258<p>The intrinsic takes two arguments, the first a pointer to an integer value
7259 and the second an integer value. The result is also an integer value. These
7260 integer types can have any bit width, but they must all have the same bit
7261 width. The targets may only lower integer representations they support.</p>
7262
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7263<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7264<p>This intrinsic does a series of operations atomically. It first loads the
7265 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7266 result to <tt>ptr</tt>. It yields the original value stored
7267 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7268
7269<h5>Examples:</h5>
7270<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7271%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7272%ptr = bitcast i8* %mallocP to i32*
7273 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7274%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7275 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7276%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7277 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7278%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7279 <i>; yields {i32}:result3 = 2</i>
7280%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7281</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7282
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7283</div>
7284
7285<!-- _______________________________________________________________________ -->
7286<div class="doc_subsubsection">
7287 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7288 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7289 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7290 <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]7291</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7292
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7293<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7294
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7295<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7296<p>These are overloaded intrinsics. You can
7297 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7298 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7299 bit width and for different address spaces. Not all targets support all bit
7300 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7301
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7302<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7303 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7304 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7305 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7306 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]7307</pre>
7308
7309<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7310 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7311 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7312 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7313 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]7314</pre>
7315
7316<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7317 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7318 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7319 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7320 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]7321</pre>
7322
7323<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7324 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7325 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7326 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7327 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]7328</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7329
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7330<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7331<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7332 the value stored in memory at <tt>ptr</tt>. It yields the original value
7333 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7335<h5>Arguments:</h5>
7336<p>These intrinsics take two arguments, the first a pointer to an integer value
7337 and the second an integer value. The result is also an integer value. These
7338 integer types can have any bit width, but they must all have the same bit
7339 width. The targets may only lower integer representations they support.</p>
7340
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7342<p>These intrinsics does a series of operations atomically. They first load the
7343 value stored at <tt>ptr</tt>. They then do the bitwise
7344 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7345 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7346
7347<h5>Examples:</h5>
7348<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7349%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7350%ptr = bitcast i8* %mallocP to i32*
7351 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7352%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7353 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7354%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7355 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7356%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7357 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7358%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7359 <i>; yields {i32}:result3 = FF</i>
7360%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7361</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7362
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7363</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7364
7365<!-- _______________________________________________________________________ -->
7366<div class="doc_subsubsection">
7367 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7368 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7369 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7370 <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]7371</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7372
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7373<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7374
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7375<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7376<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7377 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7378 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7379 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7381<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7382 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7383 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7384 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7385 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]7386</pre>
7387
7388<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7389 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7390 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7391 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7392 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]7393</pre>
7394
7395<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7396 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7397 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7398 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7399 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]7400</pre>
7401
7402<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7403 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7404 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7405 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7406 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]7407</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7408
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7409<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7410<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7411 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7412 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7413
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7414<h5>Arguments:</h5>
7415<p>These intrinsics take two arguments, the first a pointer to an integer value
7416 and the second an integer value. The result is also an integer value. These
7417 integer types can have any bit width, but they must all have the same bit
7418 width. The targets may only lower integer representations they support.</p>
7419
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7420<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421<p>These intrinsics does a series of operations atomically. They first load the
7422 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7423 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7424 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7425
7426<h5>Examples:</h5>
7427<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7428%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7429%ptr = bitcast i8* %mallocP to i32*
7430 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7431%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7432 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7433%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7434 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7435%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7436 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7437%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7438 <i>; yields {i32}:result3 = 8</i>
7439%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7440</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7441
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7442</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7443
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7444
7445<!-- ======================================================================= -->
7446<div class="doc_subsection">
7447 <a name="int_memorymarkers">Memory Use Markers</a>
7448</div>
7449
7450<div class="doc_text">
7451
7452<p>This class of intrinsics exists to information about the lifetime of memory
7453 objects and ranges where variables are immutable.</p>
7454
7455</div>
7456
7457<!-- _______________________________________________________________________ -->
7458<div class="doc_subsubsection">
7459 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7460</div>
7461
7462<div class="doc_text">
7463
7464<h5>Syntax:</h5>
7465<pre>
7466 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7467</pre>
7468
7469<h5>Overview:</h5>
7470<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7471 object's lifetime.</p>
7472
7473<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7474<p>The first argument is a constant integer representing the size of the
7475 object, or -1 if it is variable sized. The second argument is a pointer to
7476 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7477
7478<h5>Semantics:</h5>
7479<p>This intrinsic indicates that before this point in the code, the value of the
7480 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]7481 never be used and has an undefined value. A load from the pointer that
7482 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7483 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7484
7485</div>
7486
7487<!-- _______________________________________________________________________ -->
7488<div class="doc_subsubsection">
7489 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7490</div>
7491
7492<div class="doc_text">
7493
7494<h5>Syntax:</h5>
7495<pre>
7496 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7497</pre>
7498
7499<h5>Overview:</h5>
7500<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7501 object's lifetime.</p>
7502
7503<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7504<p>The first argument is a constant integer representing the size of the
7505 object, or -1 if it is variable sized. The second argument is a pointer to
7506 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7507
7508<h5>Semantics:</h5>
7509<p>This intrinsic indicates that after this point in the code, the value of the
7510 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7511 never be used and has an undefined value. Any stores into the memory object
7512 following this intrinsic may be removed as dead.
7513
7514</div>
7515
7516<!-- _______________________________________________________________________ -->
7517<div class="doc_subsubsection">
7518 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7519</div>
7520
7521<div class="doc_text">
7522
7523<h5>Syntax:</h5>
7524<pre>
7525 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7526</pre>
7527
7528<h5>Overview:</h5>
7529<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7530 a memory object will not change.</p>
7531
7532<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7533<p>The first argument is a constant integer representing the size of the
7534 object, or -1 if it is variable sized. The second argument is a pointer to
7535 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7536
7537<h5>Semantics:</h5>
7538<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7539 the return value, the referenced memory location is constant and
7540 unchanging.</p>
7541
7542</div>
7543
7544<!-- _______________________________________________________________________ -->
7545<div class="doc_subsubsection">
7546 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7547</div>
7548
7549<div class="doc_text">
7550
7551<h5>Syntax:</h5>
7552<pre>
7553 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7554</pre>
7555
7556<h5>Overview:</h5>
7557<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7558 a memory object are mutable.</p>
7559
7560<h5>Arguments:</h5>
7561<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7562 The second argument is a constant integer representing the size of the
7563 object, or -1 if it is variable sized and the third argument is a pointer
7564 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7565
7566<h5>Semantics:</h5>
7567<p>This intrinsic indicates that the memory is mutable again.</p>
7568
7569</div>
7570
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7571<!-- ======================================================================= -->
7572<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7573 <a name="int_general">General Intrinsics</a>
7574</div>
7575
7576<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7577
7578<p>This class of intrinsics is designed to be generic and has no specific
7579 purpose.</p>
7580
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7581</div>
7582
7583<!-- _______________________________________________________________________ -->
7584<div class="doc_subsubsection">
7585 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7586</div>
7587
7588<div class="doc_text">
7589
7590<h5>Syntax:</h5>
7591<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7592 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]7593</pre>
7594
7595<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7596<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7597
7598<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7599<p>The first argument is a pointer to a value, the second is a pointer to a
7600 global string, the third is a pointer to a global string which is the source
7601 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7602
7603<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7604<p>This intrinsic allows annotation of local variables with arbitrary strings.
7605 This can be useful for special purpose optimizations that want to look for
7606 these annotations. These have no other defined use, they are ignored by code
7607 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7608
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7609</div>
7610
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7611<!-- _______________________________________________________________________ -->
7612<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7613 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7614</div>
7615
7616<div class="doc_text">
7617
7618<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7619<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7620 any integer bit width.</p>
7621
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7622<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7623 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7624 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7625 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7626 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7627 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]7628</pre>
7629
7630<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7631<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7632
7633<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7634<p>The first argument is an integer value (result of some expression), the
7635 second is a pointer to a global string, the third is a pointer to a global
7636 string which is the source file name, and the last argument is the line
7637 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7638
7639<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7640<p>This intrinsic allows annotations to be put on arbitrary expressions with
7641 arbitrary strings. This can be useful for special purpose optimizations that
7642 want to look for these annotations. These have no other defined use, they
7643 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7644
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7645</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7646
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7647<!-- _______________________________________________________________________ -->
7648<div class="doc_subsubsection">
7649 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7650</div>
7651
7652<div class="doc_text">
7653
7654<h5>Syntax:</h5>
7655<pre>
7656 declare void @llvm.trap()
7657</pre>
7658
7659<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7660<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7661
7662<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7663<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7664
7665<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7666<p>This intrinsics is lowered to the target dependent trap instruction. If the
7667 target does not have a trap instruction, this intrinsic will be lowered to
7668 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7669
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7670</div>
7671
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7672<!-- _______________________________________________________________________ -->
7673<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7674 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7675</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7676
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7677<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7678
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7679<h5>Syntax:</h5>
7680<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7681 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7682</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7684<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7685<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7686 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7687 ensure that it is placed on the stack before local variables.</p>
7688
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7689<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7690<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7691 arguments. The first argument is the value loaded from the stack
7692 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7693 that has enough space to hold the value of the guard.</p>
7694
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7695<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7696<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7697 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7698 stack. This is to ensure that if a local variable on the stack is
7699 overwritten, it will destroy the value of the guard. When the function exits,
7700 the guard on the stack is checked against the original guard. If they're
7701 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7702 function.</p>
7703
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7704</div>
7705
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7706<!-- _______________________________________________________________________ -->
7707<div class="doc_subsubsection">
7708 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7709</div>
7710
7711<div class="doc_text">
7712
7713<h5>Syntax:</h5>
7714<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7715 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7716 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7717</pre>
7718
7719<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7720<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7721 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7722 operation like memcpy will either overflow a buffer that corresponds to
7723 an object, or b) to determine that a runtime check for overflow isn't
7724 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7725 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7726
7727<h5>Arguments:</h5>
7728<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7729 argument is a pointer to or into the <tt>object</tt>. The second argument
7730 is a boolean 0 or 1. This argument determines whether you want the
7731 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7732 1, variables are not allowed.</p>
7733
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7734<h5>Semantics:</h5>
7735<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7736 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7737 (depending on the <tt>type</tt> argument if the size cannot be determined
7738 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7739
7740</div>
7741
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7742<!-- *********************************************************************** -->
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7744<address>
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7750 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7751 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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7753</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7754
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7756</html>