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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 207855cff9b4811004b9720f28a5bd0adf3784b7 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling207855c2010-06-29 21:24:00 +0000[diff] [blame^]27 <li><a href="#linkage_linker_weak">'<tt>linker_weak</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]55 </ol>
56 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]88 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]89 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]97 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]127 </ol>
128 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]160 </ol>
161 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]169 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]174 </ol>
175 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]176 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]190 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]200 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 </ol>
212 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]241 </ol>
242 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]244 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]258 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]259 </ol>
260 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]265 </ol>
266 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]300 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]326<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]361</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]363<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]366<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]373<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]374<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]379<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
380 LLVM infrastructure provides a verification pass that may be used to verify
381 that an LLVM module is well formed. This pass is automatically run by the
382 parser after parsing input assembly and by the optimizer before it outputs
383 bitcode. The violations pointed out by the verifier pass indicate bugs in
384 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]385
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]386</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]391<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]394<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]442%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]444</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]446<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]448<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]452</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]454<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]456<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]460%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]462</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
465 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]467<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
471 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]472 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474 <li>Unnamed temporaries are numbered sequentially</li>
475</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]476
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]477<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]478 demonstrating instructions, we will follow an instruction with a comment that
479 defines the type and name of value produced. Comments are shown in italic
480 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]482</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
484<!-- *********************************************************************** -->
485<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
486<!-- *********************************************************************** -->
487
488<!-- ======================================================================= -->
489<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
490</div>
491
492<div class="doc_text">
493
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]494<p>LLVM programs are composed of "Module"s, each of which is a translation unit
495 of the input programs. Each module consists of functions, global variables,
496 and symbol table entries. Modules may be combined together with the LLVM
497 linker, which merges function (and global variable) definitions, resolves
498 forward declarations, and merges symbol table entries. Here is an example of
499 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]501<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]502<pre>
503<i>; Declare the string constant as a global constant.</i>
504<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
506<i>; External declaration of the puts function</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]507<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508
509<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]510define i32 @main() { <i>; i32()* </i>
511 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]512 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]513
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]514 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]515 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]516 <a href="#i_ret">ret</a> i32 0<br>}
517
518<i>; Named metadata</i>
519!1 = metadata !{i32 41}
520!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]521</pre>
522</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]524<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]525 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]527 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
528 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530<p>In general, a module is made up of a list of global values, where both
531 functions and global variables are global values. Global values are
532 represented by a pointer to a memory location (in this case, a pointer to an
533 array of char, and a pointer to a function), and have one of the
534 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]535
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="linkage">Linkage Types</a>
541</div>
542
543<div class="doc_text">
544
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]545<p>All Global Variables and Functions have one of the following types of
546 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]547
548<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling207855c2010-06-29 21:24:00 +0000[diff] [blame^]550 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
551 by objects in the current module. In particular, linking code into a
552 module with an private global value may cause the private to be renamed as
553 necessary to avoid collisions. Because the symbol is private to the
554 module, all references can be updated. This doesn't show up in any symbol
555 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]556
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling207855c2010-06-29 21:24:00 +0000[diff] [blame^]558 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
559 assembler and removed by the linker after evaluation. Note that (unlike
560 <tt>private</tt> symbols) <tt>linker_private</tt> symbols are subject to
561 coalescing by the linker: weak symbols get merged and redefinitions are
562 rejected. However, unlike normal strong symbols, they are removed by the
563 linker from the final linked image (executable or dynamic library).</dd>
564
565 <dt><tt><b><a name="linkage_linker_weak">linker_weak</a></b></tt></dt>
566 <dd>Global values with "<tt>linker_weak</tt>" linkage are given weak linkage,
567 but are removed by the linker after evaluation.</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling207855c2010-06-29 21:24:00 +0000[diff] [blame^]570 <dd>Similar to <tt>private</tt>, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
631 that only equivalent globals are ever merged (the "one definition rule" -
632 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]636
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
796<div class="doc_code">
797<pre>
798%mytype = type { %mytype*, i32 }
799</pre>
800</div>
801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802<p>You may give a name to any <a href="#typesystem">type</a> except
803 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
804 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
806<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 and that you can therefore specify multiple names for the same type. This
808 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
809 uses structural typing, the name is not part of the type. When printing out
810 LLVM IR, the printer will pick <em>one name</em> to render all types of a
811 particular shape. This means that if you have code where two different
812 source types end up having the same LLVM type, that the dumper will sometimes
813 print the "wrong" or unexpected type. This is an important design point and
814 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]815
816</div>
817
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]818<!-- ======================================================================= -->
819<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]820 <a name="globalvars">Global Variables</a>
821</div>
822
823<div class="doc_text">
824
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]825<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826 instead of run-time. Global variables may optionally be initialized, may
827 have an explicit section to be placed in, and may have an optional explicit
828 alignment specified. A variable may be defined as "thread_local", which
829 means that it will not be shared by threads (each thread will have a
830 separated copy of the variable). A variable may be defined as a global
831 "constant," which indicates that the contents of the variable
832 will <b>never</b> be modified (enabling better optimization, allowing the
833 global data to be placed in the read-only section of an executable, etc).
834 Note that variables that need runtime initialization cannot be marked
835 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
838 constant, even if the final definition of the global is not. This capability
839 can be used to enable slightly better optimization of the program, but
840 requires the language definition to guarantee that optimizations based on the
841 'constantness' are valid for the translation units that do not include the
842 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]843
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]844<p>As SSA values, global variables define pointer values that are in scope
845 (i.e. they dominate) all basic blocks in the program. Global variables
846 always define a pointer to their "content" type because they describe a
847 region of memory, and all memory objects in LLVM are accessed through
848 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]850<p>A global variable may be declared to reside in a target-specific numbered
851 address space. For targets that support them, address spaces may affect how
852 optimizations are performed and/or what target instructions are used to
853 access the variable. The default address space is zero. The address space
854 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]855
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]856<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]857 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]858
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]859<p>An explicit alignment may be specified for a global, which must be a power
860 of 2. If not present, or if the alignment is set to zero, the alignment of
861 the global is set by the target to whatever it feels convenient. If an
862 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]863 alignment. Targets and optimizers are not allowed to over-align the global
864 if the global has an assigned section. In this case, the extra alignment
865 could be observable: for example, code could assume that the globals are
866 densely packed in their section and try to iterate over them as an array,
867 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]869<p>For example, the following defines a global in a numbered address space with
870 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]871
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]872<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]875</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]876</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]878</div>
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
883 <a name="functionstructure">Functions</a>
884</div>
885
886<div class="doc_text">
887
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]888<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]889 optional <a href="#linkage">linkage type</a>, an optional
890 <a href="#visibility">visibility style</a>, an optional
891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>, a return type, an optional
903 <a href="#paramattrs">parameter attribute</a> for the return type, a function
904 name, a possibly empty list of arguments, an optional alignment, and an
905 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]906
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]907<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908 (Control Flow Graph) for the function. Each basic block may optionally start
909 with a label (giving the basic block a symbol table entry), contains a list
910 of instructions, and ends with a <a href="#terminators">terminator</a>
911 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]913<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 executed on entrance to the function, and it is not allowed to have
915 predecessor basic blocks (i.e. there can not be any branches to the entry
916 block of a function). Because the block can have no predecessors, it also
917 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]919<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]921
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]923 the alignment is set to zero, the alignment of the function is set by the
924 target to whatever it feels convenient. If an explicit alignment is
925 specified, the function is forced to have at least that much alignment. All
926 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]927
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]928<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]929<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]930<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]931define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
933 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
934 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
935 [<a href="#gc">gc</a>] { ... }
936</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]937</div>
938
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]939</div>
940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<!-- ======================================================================= -->
942<div class="doc_subsection">
943 <a name="aliasstructure">Aliases</a>
944</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]946<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947
948<p>Aliases act as "second name" for the aliasee value (which can be either
949 function, global variable, another alias or bitcast of global value). Aliases
950 may have an optional <a href="#linkage">linkage type</a>, and an
951 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]953<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]954<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]955<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]956@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]957</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]958</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
960</div>
961
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]962<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]963<div class="doc_subsection">
964 <a name="namedmetadatastructure">Named Metadata</a>
965</div>
966
967<div class="doc_text">
968
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
970 nodes</a> (but not metadata strings) and null are the only valid operands for
971 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
974<div class="doc_code">
975<pre>
976!1 = metadata !{metadata !"one"}
977!name = !{null, !1}
978</pre>
979</div>
980
981</div>
982
983<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]984<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]985
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986<div class="doc_text">
987
988<p>The return type and each parameter of a function type may have a set of
989 <i>parameter attributes</i> associated with them. Parameter attributes are
990 used to communicate additional information about the result or parameters of
991 a function. Parameter attributes are considered to be part of the function,
992 not of the function type, so functions with different parameter attributes
993 can have the same function type.</p>
994
995<p>Parameter attributes are simple keywords that follow the type specified. If
996 multiple parameter attributes are needed, they are space separated. For
997 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998
999<div class="doc_code">
1000<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1001declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1002declare i32 @atoi(i8 zeroext)
1003declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1004</pre>
1005</div>
1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1008 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be zero-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be sign-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that this parameter or return value should be treated in a
1025 special target-dependent fashion during while emitting code for a function
1026 call or return (usually, by putting it in a register as opposed to memory,
1027 though some targets use it to distinguish between two different kinds of
1028 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that the pointer parameter should really be passed by value
1032 to the function. The attribute implies that a hidden copy of the pointee
1033 is made between the caller and the callee, so the callee is unable to
1034 modify the value in the callee. This attribute is only valid on LLVM
1035 pointer arguments. It is generally used to pass structs and arrays by
1036 value, but is also valid on pointers to scalars. The copy is considered
1037 to belong to the caller not the callee (for example,
1038 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1039 <tt>byval</tt> parameters). This is not a valid attribute for return
1040 values. The byval attribute also supports specifying an alignment with
1041 the align attribute. This has a target-specific effect on the code
1042 generator that usually indicates a desired alignment for the synthesized
1043 stack slot.</dd>
1044
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This indicates that the pointer parameter specifies the address of a
1047 structure that is the return value of the function in the source program.
1048 This pointer must be guaranteed by the caller to be valid: loads and
1049 stores to the structure may be assumed by the callee to not to trap. This
1050 may only be applied to the first parameter. This is not a valid attribute
1051 for return values. </dd>
1052
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1053 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1054 <dd>This indicates that the pointer does not alias any global or any other
1055 parameter. The caller is responsible for ensuring that this is the
1056 case. On a function return value, <tt>noalias</tt> additionally indicates
1057 that the pointer does not alias any other pointers visible to the
1058 caller. For further details, please see the discussion of the NoAlias
1059 response in
1060 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1061 analysis</a>.</dd>
1062
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the callee does not make any copies of the pointer
1065 that outlive the callee itself. This is not a valid attribute for return
1066 values.</dd>
1067
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1068 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the pointer parameter can be excised using the
1070 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1071 attribute for return values.</dd>
1072</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1073
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1074</div>
1075
1076<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1077<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1078 <a name="gc">Garbage Collector Names</a>
1079</div>
1080
1081<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1083<p>Each function may specify a garbage collector name, which is simply a
1084 string:</p>
1085
1086<div class="doc_code">
1087<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1088define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089</pre>
1090</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1091
1092<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093 collector which will cause the compiler to alter its output in order to
1094 support the named garbage collection algorithm.</p>
1095
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1100 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1101</div>
1102
1103<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are set to communicate additional information about a
1106 function. Function attributes are considered to be part of the function, not
1107 of the function type, so functions with different parameter attributes can
1108 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1110<p>Function attributes are simple keywords that follow the type specified. If
1111 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1112
1113<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1114<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1115define void @f() noinline { ... }
1116define void @f() alwaysinline { ... }
1117define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1118define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1119</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1120</div>
1121
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1122<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1123 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1124 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1125 the backend should forcibly align the stack pointer. Specify the
1126 desired alignment, which must be a power of two, in parentheses.
1127
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1128 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute indicates that the inliner should attempt to inline this
1130 function into callers whenever possible, ignoring any active inlining size
1131 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1132
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1133 <dt><tt><b>inlinehint</b></tt></dt>
1134 <dd>This attribute indicates that the source code contained a hint that inlining
1135 this function is desirable (such as the "inline" keyword in C/C++). It
1136 is just a hint; it imposes no requirements on the inliner.</dd>
1137
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute indicates that the inliner should never inline this
1140 function in any situation. This attribute may not be used together with
1141 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute suggests that optimization passes and code generator passes
1145 make choices that keep the code size of this function low, and otherwise
1146 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1147
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns
1150 normally. This produces undefined behavior at runtime if the function
1151 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1152
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This function attribute indicates that the function never returns with an
1155 unwind or exceptional control flow. If the function does unwind, its
1156 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1157
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the function computes its result (or decides
1160 to unwind an exception) based strictly on its arguments, without
1161 dereferencing any pointer arguments or otherwise accessing any mutable
1162 state (e.g. memory, control registers, etc) visible to caller functions.
1163 It does not write through any pointer arguments
1164 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1165 changes any state visible to callers. This means that it cannot unwind
1166 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1167 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1168
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1169 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1170 <dd>This attribute indicates that the function does not write through any
1171 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1172 arguments) or otherwise modify any state (e.g. memory, control registers,
1173 etc) visible to caller functions. It may dereference pointer arguments
1174 and read state that may be set in the caller. A readonly function always
1175 returns the same value (or unwinds an exception identically) when called
1176 with the same set of arguments and global state. It cannot unwind an
1177 exception by calling the <tt>C++</tt> exception throwing methods, but may
1178 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1179
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the function should emit a stack smashing
1182 protector. It is in the form of a "canary"&mdash;a random value placed on
1183 the stack before the local variables that's checked upon return from the
1184 function to see if it has been overwritten. A heuristic is used to
1185 determine if a function needs stack protectors or not.<br>
1186<br>
1187 If a function that has an <tt>ssp</tt> attribute is inlined into a
1188 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1189 function will have an <tt>ssp</tt> attribute.</dd>
1190
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the function should <em>always</em> emit a
1193 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1194 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1195<br>
1196 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1197 function that doesn't have an <tt>sspreq</tt> attribute or which has
1198 an <tt>ssp</tt> attribute, then the resulting function will have
1199 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1200
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1201 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1202 <dd>This attribute indicates that the code generator should not use a red
1203 zone, even if the target-specific ABI normally permits it.</dd>
1204
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This attributes disables implicit floating point instructions.</dd>
1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute disables prologue / epilogue emission for the function.
1210 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1211</dl>
1212
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1213</div>
1214
1215<!-- ======================================================================= -->
1216<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1217 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1218</div>
1219
1220<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1221
1222<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1223 the GCC "file scope inline asm" blocks. These blocks are internally
1224 concatenated by LLVM and treated as a single unit, but may be separated in
1225 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1226
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1227<div class="doc_code">
1228<pre>
1229module asm "inline asm code goes here"
1230module asm "more can go here"
1231</pre>
1232</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1233
1234<p>The strings can contain any character by escaping non-printable characters.
1235 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]1236 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1237
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1238<p>The inline asm code is simply printed to the machine code .s file when
1239 assembly code is generated.</p>
1240
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1241</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1242
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1243<!-- ======================================================================= -->
1244<div class="doc_subsection">
1245 <a name="datalayout">Data Layout</a>
1246</div>
1247
1248<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1249
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1250<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1251 data is to be laid out in memory. The syntax for the data layout is
1252 simply:</p>
1253
1254<div class="doc_code">
1255<pre>
1256target datalayout = "<i>layout specification</i>"
1257</pre>
1258</div>
1259
1260<p>The <i>layout specification</i> consists of a list of specifications
1261 separated by the minus sign character ('-'). Each specification starts with
1262 a letter and may include other information after the letter to define some
1263 aspect of the data layout. The specifications accepted are as follows:</p>
1264
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1265<dl>
1266 <dt><tt>E</tt></dt>
1267 <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]1268 bits with the most significance have the lowest address location.</dd>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1271 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1272 the bits with the least significance have the lowest address
1273 location.</dd>
1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1276 <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]1277 <i>preferred</i> alignments. All sizes are in bits. Specifying
1278 the <i>pref</i> alignment is optional. If omitted, the
1279 preceding <tt>:</tt> should be omitted too.</dd>
1280
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1281 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1282 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1283 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1284
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1285 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1286 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1287 <i>size</i>.</dd>
1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1290 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1291 <i>size</i>. Only values of <i>size</i> that are supported by the target
1292 will work. 32 (float) and 64 (double) are supported on all targets;
1293 80 or 128 (different flavors of long double) are also supported on some
1294 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1296 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1297 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1298 <i>size</i>.</dd>
1299
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1300 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1301 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1302 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1303
1304 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1305 <dd>This specifies a set of native integer widths for the target CPU
1306 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1307 "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]1308 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1309 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1310</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1311
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1313 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1314 specifications in the <tt>datalayout</tt> keyword. The default specifications
1315 are given in this list:</p>
1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317<ul>
1318 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1319 <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]1320 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1321 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1322 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1323 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1324 <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]1325 alignment of 64-bits</li>
1326 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1327 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1328 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1329 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1330 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1331 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1332</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>When LLVM is determining the alignment for a given type, it uses the
1335 following rules:</p>
1336
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337<ol>
1338 <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]1339 specification is used.</li>
1340
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1341 <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]1342 smallest integer type that is larger than the bitwidth of the sought type
1343 is used. If none of the specifications are larger than the bitwidth then
1344 the the largest integer type is used. For example, given the default
1345 specifications above, the i7 type will use the alignment of i8 (next
1346 largest) while both i65 and i256 will use the alignment of i64 (largest
1347 specified).</li>
1348
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1349 <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]1350 largest vector type that is smaller than the sought vector type will be
1351 used as a fall back. This happens because &lt;128 x double&gt; can be
1352 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1353</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1354
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1355</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1356
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1357<!-- ======================================================================= -->
1358<div class="doc_subsection">
1359 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1360</div>
1361
1362<div class="doc_text">
1363
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1364<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1365with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1366is undefined. Pointer values are associated with address ranges
1367according to the following rules:</p>
1368
1369<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1370 <li>A pointer value formed from a
1371 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1372 is associated with the addresses associated with the first operand
1373 of the <tt>getelementptr</tt>.</li>
1374 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1375 range of the variable's storage.</li>
1376 <li>The result value of an allocation instruction is associated with
1377 the address range of the allocated storage.</li>
1378 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1379 no address.</li>
1380 <li>A pointer value formed by an
1381 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1382 address ranges of all pointer values that contribute (directly or
1383 indirectly) to the computation of the pointer's value.</li>
1384 <li>The result value of a
1385 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1386 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1387 <li>An integer constant other than zero or a pointer value returned
1388 from a function not defined within LLVM may be associated with address
1389 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1390 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1391 allocated by mechanisms provided by LLVM.</li>
1392 </ul>
1393
1394<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1395<tt><a href="#i_load">load</a></tt> merely indicates the size and
1396alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1397interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1398<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1399and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1400
1401<p>Consequently, type-based alias analysis, aka TBAA, aka
1402<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1403LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1404additional information which specialized optimization passes may use
1405to implement type-based alias analysis.</p>
1406
1407</div>
1408
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1409<!-- ======================================================================= -->
1410<div class="doc_subsection">
1411 <a name="volatile">Volatile Memory Accesses</a>
1412</div>
1413
1414<div class="doc_text">
1415
1416<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1417href="#i_store"><tt>store</tt></a>s, and <a
1418href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1419The optimizers must not change the number of volatile operations or change their
1420order of execution relative to other volatile operations. The optimizers
1421<i>may</i> change the order of volatile operations relative to non-volatile
1422operations. This is not Java's "volatile" and has no cross-thread
1423synchronization behavior.</p>
1424
1425</div>
1426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1427<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1428<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1429<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1430
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1431<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1432
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1433<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1434 intermediate representation. Being typed enables a number of optimizations
1435 to be performed on the intermediate representation directly, without having
1436 to do extra analyses on the side before the transformation. A strong type
1437 system makes it easier to read the generated code and enables novel analyses
1438 and transformations that are not feasible to perform on normal three address
1439 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1440
1441</div>
1442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1443<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1444<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1448
1449<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1450
1451<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1452 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1453 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1455 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1456 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1457 </tr>
1458 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1459 <td><a href="#t_floating">floating point</a></td>
1460 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461 </tr>
1462 <tr>
1463 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1464 <td><a href="#t_integer">integer</a>,
1465 <a href="#t_floating">floating point</a>,
1466 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1467 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1468 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1469 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1470 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1471 <a href="#t_label">label</a>,
1472 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1473 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1475 <tr>
1476 <td><a href="#t_primitive">primitive</a></td>
1477 <td><a href="#t_label">label</a>,
1478 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1479 <a href="#t_floating">floating point</a>,
1480 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481 </tr>
1482 <tr>
1483 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1484 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1485 <a href="#t_function">function</a>,
1486 <a href="#t_pointer">pointer</a>,
1487 <a href="#t_struct">structure</a>,
1488 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1489 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1490 <a href="#t_vector">vector</a>,
1491 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1492 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1493 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1494 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1495</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1496
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1497<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1498 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1499 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1501</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1503<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1504<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1505
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1507
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1508<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1509 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1510
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1511</div>
1512
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1513<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1514<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1515
1516<div class="doc_text">
1517
1518<h5>Overview:</h5>
1519<p>The integer type is a very simple type that simply specifies an arbitrary
1520 bit width for the integer type desired. Any bit width from 1 bit to
1521 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1522
1523<h5>Syntax:</h5>
1524<pre>
1525 iN
1526</pre>
1527
1528<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1529 value.</p>
1530
1531<h5>Examples:</h5>
1532<table class="layout">
1533 <tr class="layout">
1534 <td class="left"><tt>i1</tt></td>
1535 <td class="left">a single-bit integer.</td>
1536 </tr>
1537 <tr class="layout">
1538 <td class="left"><tt>i32</tt></td>
1539 <td class="left">a 32-bit integer.</td>
1540 </tr>
1541 <tr class="layout">
1542 <td class="left"><tt>i1942652</tt></td>
1543 <td class="left">a really big integer of over 1 million bits.</td>
1544 </tr>
1545</table>
1546
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1547</div>
1548
1549<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1550<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1551
1552<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1553
1554<table>
1555 <tbody>
1556 <tr><th>Type</th><th>Description</th></tr>
1557 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1558 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1559 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1560 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1561 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1562 </tbody>
1563</table>
1564
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1565</div>
1566
1567<!-- _______________________________________________________________________ -->
1568<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1569
1570<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1571
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1572<h5>Overview:</h5>
1573<p>The void type does not represent any value and has no size.</p>
1574
1575<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1576<pre>
1577 void
1578</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1580</div>
1581
1582<!-- _______________________________________________________________________ -->
1583<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1584
1585<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1586
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1587<h5>Overview:</h5>
1588<p>The label type represents code labels.</p>
1589
1590<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1591<pre>
1592 label
1593</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1594
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1595</div>
1596
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1597<!-- _______________________________________________________________________ -->
1598<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1599
1600<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1601
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1602<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1603<p>The metadata type represents embedded metadata. No derived types may be
1604 created from metadata except for <a href="#t_function">function</a>
1605 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1606
1607<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1608<pre>
1609 metadata
1610</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1611
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1612</div>
1613
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1614
1615<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1616<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1617
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1618<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1619
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1620<p>The real power in LLVM comes from the derived types in the system. This is
1621 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1622 useful types. Each of these types contain one or more element types which
1623 may be a primitive type, or another derived type. For example, it is
1624 possible to have a two dimensional array, using an array as the element type
1625 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1626
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1627
1628</div>
1629
1630<!-- _______________________________________________________________________ -->
1631<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1632
1633<div class="doc_text">
1634
1635<p>Aggregate Types are a subset of derived types that can contain multiple
1636 member types. <a href="#t_array">Arrays</a>,
1637 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1638 <a href="#t_union">unions</a> are aggregate types.</p>
1639
1640</div>
1641
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1642</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1643
1644<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1645<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1649<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1650<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651 sequentially in memory. The array type requires a size (number of elements)
1652 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1653
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1654<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1655<pre>
1656 [&lt;# elements&gt; x &lt;elementtype&gt;]
1657</pre>
1658
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1659<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1660 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1661
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1662<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1663<table class="layout">
1664 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1665 <td class="left"><tt>[40 x i32]</tt></td>
1666 <td class="left">Array of 40 32-bit integer values.</td>
1667 </tr>
1668 <tr class="layout">
1669 <td class="left"><tt>[41 x i32]</tt></td>
1670 <td class="left">Array of 41 32-bit integer values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>[4 x i8]</tt></td>
1674 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1675 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1676</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1677<p>Here are some examples of multidimensional arrays:</p>
1678<table class="layout">
1679 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1680 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1681 <td class="left">3x4 array of 32-bit integer values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1685 <td class="left">12x10 array of single precision floating point values.</td>
1686 </tr>
1687 <tr class="layout">
1688 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1689 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1690 </tr>
1691</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1692
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1693<p>There is no restriction on indexing beyond the end of the array implied by
1694 a static type (though there are restrictions on indexing beyond the bounds
1695 of an allocated object in some cases). This means that single-dimension
1696 'variable sized array' addressing can be implemented in LLVM with a zero
1697 length array type. An implementation of 'pascal style arrays' in LLVM could
1698 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1699
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1700</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1702<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1704
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1705<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1708<p>The function type can be thought of as a function signature. It consists of
1709 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]1710 function type is a scalar type, a void type, a struct type, or a union
1711 type. If the return type is a struct type then all struct elements must be
1712 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1715<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1716 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1717</pre>
1718
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1719<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]1720 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1721 which indicates that the function takes a variable number of arguments.
1722 Variable argument functions can access their arguments with
1723 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1724 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1725 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1726
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1727<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1728<table class="layout">
1729 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1730 <td class="left"><tt>i32 (i32)</tt></td>
1731 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1732 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1733 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1734 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1735 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1736 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1737 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1738 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1739 </td>
1740 </tr><tr class="layout">
1741 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1742 <td class="left">A vararg function that takes at least one
1743 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1744 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1745 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1746 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1747 </tr><tr class="layout">
1748 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1749 <td class="left">A function taking an <tt>i32</tt>, returning a
1750 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1751 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1752 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1757<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1759
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1760<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1761
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1762<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1763<p>The structure type is used to represent a collection of data members together
1764 in memory. The packing of the field types is defined to match the ABI of the
1765 underlying processor. The elements of a structure may be any type that has a
1766 size.</p>
1767
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1768<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1769 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1770 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1771 Structures in registers are accessed using the
1772 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1773 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1775<pre>
1776 { &lt;type list&gt; }
1777</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1778
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1779<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1780<table class="layout">
1781 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1782 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1783 <td class="left">A triple of three <tt>i32</tt> values</td>
1784 </tr><tr class="layout">
1785 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1786 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1787 second element is a <a href="#t_pointer">pointer</a> to a
1788 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1789 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1790 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1791</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1792
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1793</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1795<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1796<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1797</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1798
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1799<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1800
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1801<h5>Overview:</h5>
1802<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1803 together in memory. There is no padding between fields. Further, the
1804 alignment of a packed structure is 1 byte. The elements of a packed
1805 structure may be any type that has a size.</p>
1806
1807<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1808 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1809 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1810
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1811<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1812<pre>
1813 &lt; { &lt;type list&gt; } &gt;
1814</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1816<h5>Examples:</h5>
1817<table class="layout">
1818 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1819 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1820 <td class="left">A triple of three <tt>i32</tt> values</td>
1821 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1822 <td class="left">
1823<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1824 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1825 second element is a <a href="#t_pointer">pointer</a> to a
1826 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1827 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1828 </tr>
1829</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1830
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1831</div>
1832
1833<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1834<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1835
1836<div class="doc_text">
1837
1838<h5>Overview:</h5>
1839<p>A union type describes an object with size and alignment suitable for
1840 an object of any one of a given set of types (also known as an "untagged"
1841 union). It is similar in concept and usage to a
1842 <a href="#t_struct">struct</a>, except that all members of the union
1843 have an offset of zero. The elements of a union may be any type that has a
1844 size. Unions must have at least one member - empty unions are not allowed.
1845 </p>
1846
1847<p>The size of the union as a whole will be the size of its largest member,
1848 and the alignment requirements of the union as a whole will be the largest
1849 alignment requirement of any member.</p>
1850
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1851<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]1852 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1853 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1854 Since all members are at offset zero, the getelementptr instruction does
1855 not affect the address, only the type of the resulting pointer.</p>
1856
1857<h5>Syntax:</h5>
1858<pre>
1859 union { &lt;type list&gt; }
1860</pre>
1861
1862<h5>Examples:</h5>
1863<table class="layout">
1864 <tr class="layout">
1865 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1866 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1867 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1868 </tr><tr class="layout">
1869 <td class="left">
1870 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1871 <td class="left">A union, where the first element is a <tt>float</tt> and the
1872 second element is a <a href="#t_pointer">pointer</a> to a
1873 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1874 an <tt>i32</tt>.</td>
1875 </tr>
1876</table>
1877
1878</div>
1879
1880<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1882
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1883<div class="doc_text">
1884
1885<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1886<p>The pointer type is used to specify memory locations.
1887 Pointers are commonly used to reference objects in memory.</p>
1888
1889<p>Pointer types may have an optional address space attribute defining the
1890 numbered address space where the pointed-to object resides. The default
1891 address space is number zero. The semantics of non-zero address
1892 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1893
1894<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1895 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1896
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1897<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1898<pre>
1899 &lt;type&gt; *
1900</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1902<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1903<table class="layout">
1904 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1905 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1906 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1907 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1908 </tr>
1909 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1910 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1911 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1912 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1913 <tt>i32</tt>.</td>
1914 </tr>
1915 <tr class="layout">
1916 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1917 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1918 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1919 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1922</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1923
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1924<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1925<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1926
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1927<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1930<p>A vector type is a simple derived type that represents a vector of elements.
1931 Vector types are used when multiple primitive data are operated in parallel
1932 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1933 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1934 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1935
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1936<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1937<pre>
1938 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1939</pre>
1940
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1941<p>The number of elements is a constant integer value; elementtype may be any
1942 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1944<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1945<table class="layout">
1946 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1947 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1948 <td class="left">Vector of 4 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1952 <td class="left">Vector of 8 32-bit floating-point values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1956 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1957 </tr>
1958</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1960</div>
1961
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1962<!-- _______________________________________________________________________ -->
1963<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1964<div class="doc_text">
1965
1966<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1968 corresponds (for example) to the C notion of a forward declared structure
1969 type. In LLVM, opaque types can eventually be resolved to any type (not just
1970 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971
1972<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1973<pre>
1974 opaque
1975</pre>
1976
1977<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978<table class="layout">
1979 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1980 <td class="left"><tt>opaque</tt></td>
1981 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1982 </tr>
1983</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1985</div>
1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<!-- ======================================================================= -->
1988<div class="doc_subsection">
1989 <a name="t_uprefs">Type Up-references</a>
1990</div>
1991
1992<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1995<p>An "up reference" allows you to refer to a lexically enclosing type without
1996 requiring it to have a name. For instance, a structure declaration may
1997 contain a pointer to any of the types it is lexically a member of. Example
1998 of up references (with their equivalent as named type declarations)
1999 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000
2001<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2002 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2003 { \2 }* %y = type { %y }*
2004 \1* %z = type %z*
2005</pre>
2006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2007<p>An up reference is needed by the asmprinter for printing out cyclic types
2008 when there is no declared name for a type in the cycle. Because the
2009 asmprinter does not want to print out an infinite type string, it needs a
2010 syntax to handle recursive types that have no names (all names are optional
2011 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Syntax:</h5>
2014<pre>
2015 \&lt;level&gt;
2016</pre>
2017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2018<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]2019
2020<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
2023 <td class="left"><tt>\1*</tt></td>
2024 <td class="left">Self-referential pointer.</td>
2025 </tr>
2026 <tr class="layout">
2027 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2028 <td class="left">Recursive structure where the upref refers to the out-most
2029 structure.</td>
2030 </tr>
2031</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2032
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2034
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2035<!-- *********************************************************************** -->
2036<div class="doc_section"> <a name="constants">Constants</a> </div>
2037<!-- *********************************************************************** -->
2038
2039<div class="doc_text">
2040
2041<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043
2044</div>
2045
2046<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2047<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049<div class="doc_text">
2050
2051<dl>
2052 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2054 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2057 <dd>Standard integers (such as '4') are constants of
2058 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2059 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2060
2061 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2062 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2063 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2064 notation (see below). The assembler requires the exact decimal value of a
2065 floating-point constant. For example, the assembler accepts 1.25 but
2066 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2067 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2068
2069 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2070 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2072</dl>
2073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2074<p>The one non-intuitive notation for constants is the hexadecimal form of
2075 floating point constants. For example, the form '<tt>double
2076 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2077 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2078 constants are required (and the only time that they are generated by the
2079 disassembler) is when a floating point constant must be emitted but it cannot
2080 be represented as a decimal floating point number in a reasonable number of
2081 digits. For example, NaN's, infinities, and other special values are
2082 represented in their IEEE hexadecimal format so that assembly and disassembly
2083 do not cause any bits to change in the constants.</p>
2084
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2085<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2086 represented using the 16-digit form shown above (which matches the IEEE754
2087 representation for double); float values must, however, be exactly
2088 representable as IEE754 single precision. Hexadecimal format is always used
2089 for long double, and there are three forms of long double. The 80-bit format
2090 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2091 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2092 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2093 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2094 currently supported target uses this format. Long doubles will only work if
2095 they match the long double format on your target. All hexadecimal formats
2096 are big-endian (sign bit at the left).</p>
2097
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2098</div>
2099
2100<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2101<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2102<a name="aggregateconstants"></a> <!-- old anchor -->
2103<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2104</div>
2105
2106<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2108<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2109 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2110
2111<dl>
2112 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2113 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2114 type definitions (a comma separated list of elements, surrounded by braces
2115 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2116 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2117 Structure constants must have <a href="#t_struct">structure type</a>, and
2118 the number and types of elements must match those specified by the
2119 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2120
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2121 <dt><b>Union constants</b></dt>
2122 <dd>Union constants are represented with notation similar to a structure with
2123 a single element - that is, a single typed element surrounded
2124 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2125 <a href="#t_union">union type</a> can be initialized with a single-element
2126 struct as long as the type of the struct element matches the type of
2127 one of the union members.</dd>
2128
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2130 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2131 definitions (a comma separated list of elements, surrounded by square
2132 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2133 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2134 the number and types of elements must match those specified by the
2135 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2136
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2137 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2138 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2139 definitions (a comma separated list of elements, surrounded by
2140 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2141 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2142 have <a href="#t_vector">vector type</a>, and the number and types of
2143 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2144
2145 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2146 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2147 value to zero of <em>any</em> type, including scalar and
2148 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149 This is often used to avoid having to print large zero initializers
2150 (e.g. for large arrays) and is always exactly equivalent to using explicit
2151 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2152
2153 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2154 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2155 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2156 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2157 be interpreted as part of the instruction stream, metadata is a place to
2158 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2159</dl>
2160
2161</div>
2162
2163<!-- ======================================================================= -->
2164<div class="doc_subsection">
2165 <a name="globalconstants">Global Variable and Function Addresses</a>
2166</div>
2167
2168<div class="doc_text">
2169
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2170<p>The addresses of <a href="#globalvars">global variables</a>
2171 and <a href="#functionstructure">functions</a> are always implicitly valid
2172 (link-time) constants. These constants are explicitly referenced when
2173 the <a href="#identifiers">identifier for the global</a> is used and always
2174 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2175 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2176
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2177<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2178<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2179@X = global i32 17
2180@Y = global i32 42
2181@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2182</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2183</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2184
2185</div>
2186
2187<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2188<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2189<div class="doc_text">
2190
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2191<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]2192 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2193 Undefined values may be of any type (other than label or void) and be used
2194 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2196<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2197 program is well defined no matter what value is used. This gives the
2198 compiler more freedom to optimize. Here are some examples of (potentially
2199 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2200
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2201
2202<div class="doc_code">
2203<pre>
2204 %A = add %X, undef
2205 %B = sub %X, undef
2206 %C = xor %X, undef
2207Safe:
2208 %A = undef
2209 %B = undef
2210 %C = undef
2211</pre>
2212</div>
2213
2214<p>This is safe because all of the output bits are affected by the undef bits.
2215Any output bit can have a zero or one depending on the input bits.</p>
2216
2217<div class="doc_code">
2218<pre>
2219 %A = or %X, undef
2220 %B = and %X, undef
2221Safe:
2222 %A = -1
2223 %B = 0
2224Unsafe:
2225 %A = undef
2226 %B = undef
2227</pre>
2228</div>
2229
2230<p>These logical operations have bits that are not always affected by the input.
2231For example, if "%X" has a zero bit, then the output of the 'and' operation will
2232always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2233such, 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]2234However, it is safe to assume that all bits of the undef could be 0, and
2235optimize the and to 0. Likewise, it is safe to assume that all the bits of
2236the 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]2237-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2238
2239<div class="doc_code">
2240<pre>
2241 %A = select undef, %X, %Y
2242 %B = select undef, 42, %Y
2243 %C = select %X, %Y, undef
2244Safe:
2245 %A = %X (or %Y)
2246 %B = 42 (or %Y)
2247 %C = %Y
2248Unsafe:
2249 %A = undef
2250 %B = undef
2251 %C = undef
2252</pre>
2253</div>
2254
2255<p>This set of examples show that undefined select (and conditional branch)
2256conditions can go "either way" but they have to come from one of the two
2257operands. In the %A example, if %X and %Y were both known to have a clear low
2258bit, then %A would have to have a cleared low bit. However, in the %C example,
2259the optimizer is allowed to assume that the undef operand could be the same as
2260%Y, allowing the whole select to be eliminated.</p>
2261
2262
2263<div class="doc_code">
2264<pre>
2265 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2266
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2267 %B = undef
2268 %C = xor %B, %B
2269
2270 %D = undef
2271 %E = icmp lt %D, 4
2272 %F = icmp gte %D, 4
2273
2274Safe:
2275 %A = undef
2276 %B = undef
2277 %C = undef
2278 %D = undef
2279 %E = undef
2280 %F = undef
2281</pre>
2282</div>
2283
2284<p>This example points out that two undef operands are not necessarily the same.
2285This can be surprising to people (and also matches C semantics) where they
2286assume that "X^X" is always zero, even if X is undef. This isn't true for a
2287number of reasons, but the short answer is that an undef "variable" can
2288arbitrarily change its value over its "live range". This is true because the
2289"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2290logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2291so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2292to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2293would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2294
2295<div class="doc_code">
2296<pre>
2297 %A = fdiv undef, %X
2298 %B = fdiv %X, undef
2299Safe:
2300 %A = undef
2301b: unreachable
2302</pre>
2303</div>
2304
2305<p>These examples show the crucial difference between an <em>undefined
2306value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2307allowed to have an arbitrary bit-pattern. This means that the %A operation
2308can be constant folded to undef because the undef could be an SNaN, and fdiv is
2309not (currently) defined on SNaN's. However, in the second example, we can make
2310a more aggressive assumption: because the undef is allowed to be an arbitrary
2311value, 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]2312has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2313does not execute at all. This allows us to delete the divide and all code after
2314it: since the undefined operation "can't happen", the optimizer can assume that
2315it occurs in dead code.
2316</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2317
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2318<div class="doc_code">
2319<pre>
2320a: store undef -> %X
2321b: store %X -> undef
2322Safe:
2323a: &lt;deleted&gt;
2324b: unreachable
2325</pre>
2326</div>
2327
2328<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2329can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2330overwritten with bits that happen to match what was already there. However, a
2331store "to" an undefined location could clobber arbitrary memory, therefore, it
2332has undefined behavior.</p>
2333
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2334</div>
2335
2336<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2337<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2338<div class="doc_text">
2339
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2340<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2341 instead of representing an unspecified bit pattern, they represent the
2342 fact that an instruction or constant expression which cannot evoke side
2343 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2344 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2345
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2346<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]2347 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2348 <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]2349
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2350<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2351
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2352<p>
2353<ul>
2354<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2355 their operands.</li>
2356
2357<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2358 to their dynamic predecessor basic block.</li>
2359
2360<li>Function arguments depend on the corresponding actual argument values in
2361 the dynamic callers of their functions.</li>
2362
2363<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2364 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2365 control back to them.</li>
2366
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2367<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2368 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2369 or exception-throwing call instructions that dynamically transfer control
2370 back to them.</li>
2371
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2372<li>Non-volatile loads and stores depend on the most recent stores to all of the
2373 referenced memory addresses, following the order in the IR
2374 (including loads and stores implied by intrinsics such as
2375 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2376
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2377<!-- TODO: In the case of multiple threads, this only applies if the store
2378 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2379
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2380<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2381
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2382<li>An instruction with externally visible side effects depends on the most
2383 recent preceding instruction with externally visible side effects, following
2384 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2385
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2386<li>An instruction <i>control-depends</i> on a
2387 <a href="#terminators">terminator instruction</a>
2388 if the terminator instruction has multiple successors and the instruction
2389 is always executed when control transfers to one of the successors, and
2390 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2391
2392<li>Dependence is transitive.</li>
2393
2394</ul>
2395</p>
2396
2397<p>Whenever a trap value is generated, all values which depend on it evaluate
2398 to trap. If they have side effects, the evoke their side effects as if each
2399 operand with a trap value were undef. If they have externally-visible side
2400 effects, the behavior is undefined.</p>
2401
2402<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2403
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2404<div class="doc_code">
2405<pre>
2406entry:
2407 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2408 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2409 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2410 store i32 0, i32* %trap_yet_again ; undefined behavior
2411
2412 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2413 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2414
2415 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2416
2417 %narrowaddr = bitcast i32* @g to i16*
2418 %wideaddr = bitcast i32* @g to i64*
2419 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2420 %trap4 = load i64* %widaddr ; Returns a trap value.
2421
2422 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2423 %br i1 %cmp, %true, %end ; Branch to either destination.
2424
2425true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2426 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2427 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2428 br label %end
2429
2430end:
2431 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2432 ; Both edges into this PHI are
2433 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2434 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2435
2436 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2437 ; so this is defined (ignoring earlier
2438 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2439</pre>
2440</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2441
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2442</div>
2443
2444<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2445<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2446 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2447<div class="doc_text">
2448
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2449<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2450
2451<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2452 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2453 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2454
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2455<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2456 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2457 against null. Pointer equality tests between labels addresses is undefined
2458 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2459 equal to the null pointer. This may also be passed around as an opaque
2460 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2461 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2462 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2463
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2464<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2465 using the value as the operand to an inline assembly, but that is target
2466 specific.
2467 </p>
2468
2469</div>
2470
2471
2472<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2473<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2474</div>
2475
2476<div class="doc_text">
2477
2478<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479 to be used as constants. Constant expressions may be of
2480 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2481 operation that does not have side effects (e.g. load and call are not
2482 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2483
2484<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2486 <dd>Truncate a constant to another type. The bit size of CST must be larger
2487 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2488
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Zero extend a constant to another type. The bit size of CST must be
2491 smaller or equal to the bit size of TYPE. Both types must be
2492 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2495 <dd>Sign extend a constant to another type. The bit size of CST must be
2496 smaller or equal to the bit size of TYPE. Both types must be
2497 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2499 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2500 <dd>Truncate a floating point constant to another floating point type. The
2501 size of CST must be larger than the size of TYPE. Both types must be
2502 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2505 <dd>Floating point extend a constant to another type. The size of CST must be
2506 smaller or equal to the size of TYPE. Both types must be floating
2507 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2508
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2509 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2510 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2511 constant. TYPE must be a scalar or vector integer type. CST must be of
2512 scalar or vector floating point type. Both CST and TYPE must be scalars,
2513 or vectors of the same number of elements. If the value won't fit in the
2514 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2515
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2517 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2518 constant. TYPE must be a scalar or vector integer type. CST must be of
2519 scalar or vector floating point type. Both CST and TYPE must be scalars,
2520 or vectors of the same number of elements. If the value won't fit in the
2521 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2522
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2523 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2524 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2525 constant. TYPE must be a scalar or vector floating point type. CST must be
2526 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2527 vectors of the same number of elements. If the value won't fit in the
2528 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2529
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2530 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2531 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 constant. TYPE must be a scalar or vector floating point type. CST must be
2533 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2534 vectors of the same number of elements. If the value won't fit in the
2535 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2536
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2538 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2539 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2540 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2541 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2542
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2543 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2544 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2545 type. CST must be of integer type. The CST value is zero extended,
2546 truncated, or unchanged to make it fit in a pointer size. This one is
2547 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2548
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2550 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2551 are the same as those for the <a href="#i_bitcast">bitcast
2552 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2553
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2554 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2555 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2556 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2558 instruction, the index list may have zero or more indexes, which are
2559 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2560
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2561 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2562 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2563
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2564 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2565 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2566
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2567 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2568 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2569
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2570 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2572 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2573
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2574 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2575 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2576 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2577
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2578 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2579 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2580 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2581
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2582 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2583 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2584 constants. The index list is interpreted in a similar manner as indices in
2585 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2586 index value must be specified.</dd>
2587
2588 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2589 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2590 constants. The index list is interpreted in a similar manner as indices in
2591 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2592 index value must be specified.</dd>
2593
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2594 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2595 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2596 be any of the <a href="#binaryops">binary</a>
2597 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2598 on operands are the same as those for the corresponding instruction
2599 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2600</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2601
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2602</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2604<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2605<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2606<!-- *********************************************************************** -->
2607
2608<!-- ======================================================================= -->
2609<div class="doc_subsection">
2610<a name="inlineasm">Inline Assembler Expressions</a>
2611</div>
2612
2613<div class="doc_text">
2614
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2615<p>LLVM supports inline assembler expressions (as opposed
2616 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2617 a special value. This value represents the inline assembler as a string
2618 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2619 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2620 expression has side effects, and a flag indicating whether the function
2621 containing the asm needs to align its stack conservatively. An example
2622 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2623
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2624<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2625<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2626i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2627</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2628</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2629
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2630<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2631 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2632 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2633
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2634<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2635<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2636%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]2637</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2638</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2639
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2640<p>Inline asms with side effects not visible in the constraint list must be
2641 marked as having side effects. This is done through the use of the
2642 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2643
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2644<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2645<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2646call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2647</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2648</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2649
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2650<p>In some cases inline asms will contain code that will not work unless the
2651 stack is aligned in some way, such as calls or SSE instructions on x86,
2652 yet will not contain code that does that alignment within the asm.
2653 The compiler should make conservative assumptions about what the asm might
2654 contain and should generate its usual stack alignment code in the prologue
2655 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2656
2657<div class="doc_code">
2658<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2659call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2660</pre>
2661</div>
2662
2663<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2664 first.</p>
2665
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2666<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2667 documented here. Constraints on what can be done (e.g. duplication, moving,
2668 etc need to be documented). This is probably best done by reference to
2669 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2670</div>
2671
2672<div class="doc_subsubsection">
2673<a name="inlineasm_md">Inline Asm Metadata</a>
2674</div>
2675
2676<div class="doc_text">
2677
2678<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2679 attached to it that contains a constant integer. If present, the code
2680 generator will use the integer as the location cookie value when report
2681 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2682 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2683 source code that produced it. For example:</p>
2684
2685<div class="doc_code">
2686<pre>
2687call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2688...
2689!42 = !{ i32 1234567 }
2690</pre>
2691</div>
2692
2693<p>It is up to the front-end to make sense of the magic numbers it places in the
2694 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2695
2696</div>
2697
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2698<!-- ======================================================================= -->
2699<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2700 Strings</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<p>LLVM IR allows metadata to be attached to instructions in the program that
2706 can convey extra information about the code to the optimizers and code
2707 generator. One example application of metadata is source-level debug
2708 information. There are two metadata primitives: strings and nodes. All
2709 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2710 preceding exclamation point ('<tt>!</tt>').</p>
2711
2712<p>A metadata string is a string surrounded by double quotes. It can contain
2713 any character by escaping non-printable characters with "\xx" where "xx" is
2714 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2715
2716<p>Metadata nodes are represented with notation similar to structure constants
2717 (a comma separated list of elements, surrounded by braces and preceded by an
2718 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2719 10}</tt>". Metadata nodes can have any values as their operand.</p>
2720
2721<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2722 metadata nodes, which can be looked up in the module symbol table. For
2723 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2724
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2725<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2726 function is using two metadata arguments.
2727
2728 <div class="doc_code">
2729 <pre>
2730 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2731 </pre>
2732 </div></p>
2733
2734<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2735 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2736
2737 <div class="doc_code">
2738 <pre>
2739 %indvar.next = add i64 %indvar, 1, !dbg !21
2740 </pre>
2741 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2742</div>
2743
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2744
2745<!-- *********************************************************************** -->
2746<div class="doc_section">
2747 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2748</div>
2749<!-- *********************************************************************** -->
2750
2751<p>LLVM has a number of "magic" global variables that contain data that affect
2752code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2753of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2754section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2755by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2756
2757<!-- ======================================================================= -->
2758<div class="doc_subsection">
2759<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2760</div>
2761
2762<div class="doc_text">
2763
2764<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2765href="#linkage_appending">appending linkage</a>. This array contains a list of
2766pointers to global variables and functions which may optionally have a pointer
2767cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2768
2769<pre>
2770 @X = global i8 4
2771 @Y = global i32 123
2772
2773 @llvm.used = appending global [2 x i8*] [
2774 i8* @X,
2775 i8* bitcast (i32* @Y to i8*)
2776 ], section "llvm.metadata"
2777</pre>
2778
2779<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2780compiler, assembler, and linker are required to treat the symbol as if there is
2781a reference to the global that it cannot see. For example, if a variable has
2782internal linkage and no references other than that from the <tt>@llvm.used</tt>
2783list, it cannot be deleted. This is commonly used to represent references from
2784inline asms and other things the compiler cannot "see", and corresponds to
2785"attribute((used))" in GNU C.</p>
2786
2787<p>On some targets, the code generator must emit a directive to the assembler or
2788object file to prevent the assembler and linker from molesting the symbol.</p>
2789
2790</div>
2791
2792<!-- ======================================================================= -->
2793<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2794<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2795</div>
2796
2797<div class="doc_text">
2798
2799<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2800<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2801touching the symbol. On targets that support it, this allows an intelligent
2802linker to optimize references to the symbol without being impeded as it would be
2803by <tt>@llvm.used</tt>.</p>
2804
2805<p>This is a rare construct that should only be used in rare circumstances, and
2806should not be exposed to source languages.</p>
2807
2808</div>
2809
2810<!-- ======================================================================= -->
2811<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2812<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2813</div>
2814
2815<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2816<pre>
2817%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2818@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2819</pre>
2820<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.
2821</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2822
2823</div>
2824
2825<!-- ======================================================================= -->
2826<div class="doc_subsection">
2827<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2828</div>
2829
2830<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2831<pre>
2832%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2833@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2834</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2835
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2836<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.
2837</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2838
2839</div>
2840
2841
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2842<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2843<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2844<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2846<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2847
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2848<p>The LLVM instruction set consists of several different classifications of
2849 instructions: <a href="#terminators">terminator
2850 instructions</a>, <a href="#binaryops">binary instructions</a>,
2851 <a href="#bitwiseops">bitwise binary instructions</a>,
2852 <a href="#memoryops">memory instructions</a>, and
2853 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2854
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2855</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2857<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2858<div class="doc_subsection"> <a name="terminators">Terminator
2859Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2860
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2861<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2863<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2864 in a program ends with a "Terminator" instruction, which indicates which
2865 block should be executed after the current block is finished. These
2866 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2867 control flow, not values (the one exception being the
2868 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2869
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2870<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2871 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2872 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2873 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2874 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2875 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2876 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2877 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2879</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2881<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2882<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2883Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2884
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2885<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2887<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2888<pre>
2889 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]2890 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2891</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2895 a value) from a function back to the caller.</p>
2896
2897<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2898 value and then causes control flow, and one that just causes control flow to
2899 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2903 return value. The type of the return value must be a
2904 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2906<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2907 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2908 value or a return value with a type that does not match its type, or if it
2909 has a void return type and contains a '<tt>ret</tt>' instruction with a
2910 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2914 the calling function's context. If the caller is a
2915 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2916 instruction after the call. If the caller was an
2917 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2918 the beginning of the "normal" destination block. If the instruction returns
2919 a value, that value shall set the call or invoke instruction's return
2920 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2923<pre>
2924 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2925 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2926 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]2927</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2928
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2929</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2930<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2931<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2933<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2936<pre>
2937 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]2938</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2940<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2941<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2942 different basic block in the current function. There are two forms of this
2943 instruction, corresponding to a conditional branch and an unconditional
2944 branch.</p>
2945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2946<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2947<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2948 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2949 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2950 target.</p>
2951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2952<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2953<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2954 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2955 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2956 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2957
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2958<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2959<pre>
2960Test:
2961 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2962 br i1 %cond, label %IfEqual, label %IfUnequal
2963IfEqual:
2964 <a href="#i_ret">ret</a> i32 1
2965IfUnequal:
2966 <a href="#i_ret">ret</a> i32 0
2967</pre>
2968
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2969</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2971<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2972<div class="doc_subsubsection">
2973 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2974</div>
2975
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2976<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2978<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2979<pre>
2980 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2981</pre>
2982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2984<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]2985 several different places. It is a generalization of the '<tt>br</tt>'
2986 instruction, allowing a branch to occur to one of many possible
2987 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2989<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2991 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2992 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2993 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2994
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2995<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2996<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2997 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2998 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2999 transferred to the corresponding destination; otherwise, control flow is
3000 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3001
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3002<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3003<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3004 <tt>switch</tt> instruction, this instruction may be code generated in
3005 different ways. For example, it could be generated as a series of chained
3006 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3007
3008<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3009<pre>
3010 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3011 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3012 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3013
3014 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3015 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3016
3017 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3018 switch i32 %val, label %otherwise [ i32 0, label %onzero
3019 i32 1, label %onone
3020 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3021</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3022
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3023</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3024
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3025
3026<!-- _______________________________________________________________________ -->
3027<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3028 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3029</div>
3030
3031<div class="doc_text">
3032
3033<h5>Syntax:</h5>
3034<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3035 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]3036</pre>
3037
3038<h5>Overview:</h5>
3039
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3040<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3041 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3042 "<tt>address</tt>". Address must be derived from a <a
3043 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3044
3045<h5>Arguments:</h5>
3046
3047<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3048 rest of the arguments indicate the full set of possible destinations that the
3049 address may point to. Blocks are allowed to occur multiple times in the
3050 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3051
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3052<p>This destination list is required so that dataflow analysis has an accurate
3053 understanding of the CFG.</p>
3054
3055<h5>Semantics:</h5>
3056
3057<p>Control transfers to the block specified in the address argument. All
3058 possible destination blocks must be listed in the label list, otherwise this
3059 instruction has undefined behavior. This implies that jumps to labels
3060 defined in other functions have undefined behavior as well.</p>
3061
3062<h5>Implementation:</h5>
3063
3064<p>This is typically implemented with a jump through a register.</p>
3065
3066<h5>Example:</h5>
3067<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3068 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3069</pre>
3070
3071</div>
3072
3073
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3074<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3075<div class="doc_subsubsection">
3076 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3077</div>
3078
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3079<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3080
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3081<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3082<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3083 &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]3084 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3085</pre>
3086
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3087<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3088<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 function, with the possibility of control flow transfer to either the
3090 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3091 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3092 control flow will return to the "normal" label. If the callee (or any
3093 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3094 instruction, control is interrupted and continued at the dynamically nearest
3095 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3097<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3098<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3099
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3100<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3102 convention</a> the call should use. If none is specified, the call
3103 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3104
3105 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3106 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3107 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3108
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3109 <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]3110 function value being invoked. In most cases, this is a direct function
3111 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3112 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3113
3114 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3116
3117 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3118 signature argument types and parameter attributes. All arguments must be
3119 of <a href="#t_firstclass">first class</a> type. If the function
3120 signature indicates the function accepts a variable number of arguments,
3121 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3122
3123 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3125
3126 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3128
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3129 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3130 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3131 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3132</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3133
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3134<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135<p>This instruction is designed to operate as a standard
3136 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3137 primary difference is that it establishes an association with a label, which
3138 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3139
3140<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3141 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3142 exception. Additionally, this is important for implementation of
3143 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3144
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145<p>For the purposes of the SSA form, the definition of the value returned by the
3146 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3147 block to the "normal" label. If the callee unwinds then no return value is
3148 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3149
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3150<p>Note that the code generator does not yet completely support unwind, and
3151that the invoke/unwind semantics are likely to change in future versions.</p>
3152
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3153<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3154<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3155 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3156 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3157 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3158 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3159</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3160
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3162
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3163<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3164
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3165<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3166Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3168<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3169
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3170<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3171<pre>
3172 unwind
3173</pre>
3174
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3175<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3176<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177 at the first callee in the dynamic call stack which used
3178 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3179 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3180
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3181<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3182<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3183 immediately halt. The dynamic call stack is then searched for the
3184 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3185 Once found, execution continues at the "exceptional" destination block
3186 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3187 instruction in the dynamic call chain, undefined behavior results.</p>
3188
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3189<p>Note that the code generator does not yet completely support unwind, and
3190that the invoke/unwind semantics are likely to change in future versions.</p>
3191
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3192</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3193
3194<!-- _______________________________________________________________________ -->
3195
3196<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3197Instruction</a> </div>
3198
3199<div class="doc_text">
3200
3201<h5>Syntax:</h5>
3202<pre>
3203 unreachable
3204</pre>
3205
3206<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3207<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3208 instruction is used to inform the optimizer that a particular portion of the
3209 code is not reachable. This can be used to indicate that the code after a
3210 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3211
3212<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3213<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3214
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3215</div>
3216
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3217<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3218<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3220<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3221
3222<p>Binary operators are used to do most of the computation in a program. They
3223 require two operands of the same type, execute an operation on them, and
3224 produce a single value. The operands might represent multiple data, as is
3225 the case with the <a href="#t_vector">vector</a> data type. The result value
3226 has the same type as its operands.</p>
3227
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3228<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3229
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3230</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3232<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3233<div class="doc_subsubsection">
3234 <a name="i_add">'<tt>add</tt>' Instruction</a>
3235</div>
3236
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3237<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3239<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3240<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3241 &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]3242 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3243 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3244 &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]3245</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3247<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3248<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3249
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3250<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3251<p>The two arguments to the '<tt>add</tt>' instruction must
3252 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3253 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3255<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3256<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3257
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3258<p>If the sum has unsigned overflow, the result returned is the mathematical
3259 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]3260
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3261<p>Because LLVM integers use a two's complement representation, this instruction
3262 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3263
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3264<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3265 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3266 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3267 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3268 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3269
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3270<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3271<pre>
3272 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3273</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3275</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3278<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3280</div>
3281
3282<div class="doc_text">
3283
3284<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3285<pre>
3286 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3287</pre>
3288
3289<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3290<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3291
3292<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3293<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3295 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3296
3297<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3298<p>The value produced is the floating point sum of the two operands.</p>
3299
3300<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3301<pre>
3302 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3303</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3304
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3305</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3306
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3309 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3310</div>
3311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3312<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3313
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3314<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3315<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3316 &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]3317 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3318 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3319 &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]3320</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3322<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3323<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3325
3326<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3327 '<tt>neg</tt>' instruction present in most other intermediate
3328 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3329
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331<p>The two arguments to the '<tt>sub</tt>' instruction must
3332 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3333 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3335<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3336<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3337
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3338<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3339 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3340 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342<p>Because LLVM integers use a two's complement representation, this instruction
3343 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3344
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3345<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3346 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3347 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3348 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3349 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3352<pre>
3353 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3354 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3355</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3356
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3357</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3360<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3361 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3362</div>
3363
3364<div class="doc_text">
3365
3366<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3367<pre>
3368 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3369</pre>
3370
3371<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3372<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3374
3375<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3376 '<tt>fneg</tt>' instruction present in most other intermediate
3377 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3378
3379<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3380<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3381 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3382 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3383
3384<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3385<p>The value produced is the floating point difference of the two operands.</p>
3386
3387<h5>Example:</h5>
3388<pre>
3389 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3390 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3393</div>
3394
3395<!-- _______________________________________________________________________ -->
3396<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3397 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3398</div>
3399
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3400<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3402<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3404 &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]3405 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3406 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3407 &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]3408</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3411<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414<p>The two arguments to the '<tt>mul</tt>' instruction must
3415 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3416 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3417
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3418<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3419<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3420
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421<p>If the result of the multiplication has unsigned overflow, the result
3422 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3423 width of the result.</p>
3424
3425<p>Because LLVM integers use a two's complement representation, and the result
3426 is the same width as the operands, this instruction returns the correct
3427 result for both signed and unsigned integers. If a full product
3428 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3429 be sign-extended or zero-extended as appropriate to the width of the full
3430 product.</p>
3431
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3432<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3433 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3434 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3435 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3436 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3438<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439<pre>
3440 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3441</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3443</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3445<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3446<div class="doc_subsubsection">
3447 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3448</div>
3449
3450<div class="doc_text">
3451
3452<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3453<pre>
3454 &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]3455</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3457<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3459
3460<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3461<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3463 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3464
3465<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3466<p>The value produced is the floating point product of the two operands.</p>
3467
3468<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469<pre>
3470 &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]3471</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3473</div>
3474
3475<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3477</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3479<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3481<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482<pre>
3483 &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]3484</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3485
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3486<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3490<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3492 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3493
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3494<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3495<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3497<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3499
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3500<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3502<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503<pre>
3504 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3505</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3507</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3509<!-- _______________________________________________________________________ -->
3510<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3511</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3513<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3514
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3515<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3516<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3517 &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]3518 &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]3519</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3521<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3523
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3524<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3525<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3527 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3528
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3529<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530<p>The value produced is the signed integer quotient of the two operands rounded
3531 towards zero.</p>
3532
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3533<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3535
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3536<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537 undefined behavior; this is a rare case, but can occur, for example, by doing
3538 a 32-bit division of -2147483648 by -1.</p>
3539
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3540<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3541 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3542 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3543
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3544<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545<pre>
3546 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3549</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3551<!-- _______________________________________________________________________ -->
3552<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3553Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3555<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3557<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3559 &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]3560</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3561
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562<h5>Overview:</h5>
3563<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3564
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3565<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3566<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3568 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3570<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3571<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3572
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3573<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3574<pre>
3575 &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]3576</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3579
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3580<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3581<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3582</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3584<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3586<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3587<pre>
3588 &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]3589</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3591<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3593 division of its two arguments.</p>
3594
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3595<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3596<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3597 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3598 values. Both arguments must have identical types.</p>
3599
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3600<h5>Semantics:</h5>
3601<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602 This instruction always performs an unsigned division to get the
3603 remainder.</p>
3604
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3605<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3607
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3608<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3610<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611<pre>
3612 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3613</pre>
3614
3615</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3617<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3618<div class="doc_subsubsection">
3619 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3620</div>
3621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3622<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3623
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3624<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3625<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3626 &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]3627</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3628
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3629<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3630<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3631 division of its two operands. This instruction can also take
3632 <a href="#t_vector">vector</a> versions of the values in which case the
3633 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3634
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3636<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3637 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3638 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3639
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3640<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3641<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3643 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3644 a value. For more information about the difference,
3645 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3646 Math Forum</a>. For a table of how this is implemented in various languages,
3647 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3648 Wikipedia: modulo operation</a>.</p>
3649
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3650<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3652
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3653<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3654 Overflow also leads to undefined behavior; this is a rare case, but can
3655 occur, for example, by taking the remainder of a 32-bit division of
3656 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3657 lets srem be implemented using instructions that return both the result of
3658 the division and the remainder.)</p>
3659
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3660<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661<pre>
3662 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3663</pre>
3664
3665</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3666
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3667<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3668<div class="doc_subsubsection">
3669 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3670
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3671<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3672
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3673<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674<pre>
3675 &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]3676</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3678<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3680 its two operands.</p>
3681
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3682<h5>Arguments:</h5>
3683<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3685 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3686
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3687<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688<p>This instruction returns the <i>remainder</i> of a division. The remainder
3689 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3690
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3691<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3692<pre>
3693 &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]3694</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3695
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3696</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3697
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3698<!-- ======================================================================= -->
3699<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3700Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3702<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703
3704<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3705 program. They are generally very efficient instructions and can commonly be
3706 strength reduced from other instructions. They require two operands of the
3707 same type, execute an operation on them, and produce a single value. The
3708 resulting value is the same type as its operands.</p>
3709
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3710</div>
3711
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3714Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3717
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3718<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3719<pre>
3720 &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]3721</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3722
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3723<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3725 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3726
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3727<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3729 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3730 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3731
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3732<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3734 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3735 is (statically or dynamically) negative or equal to or larger than the number
3736 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3737 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3738 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3739
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<h5>Example:</h5>
3741<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3742 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3743 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3744 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3745 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3746 &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]3747</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3749</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3751<!-- _______________________________________________________________________ -->
3752<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3753Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3755<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3757<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &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]3760</pre>
3761
3762<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3763<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3764 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3765
3766<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3767<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3768 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3769 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3770
3771<h5>Semantics:</h5>
3772<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773 significant bits of the result will be filled with zero bits after the shift.
3774 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3775 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3776 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3777 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3778
3779<h5>Example:</h5>
3780<pre>
3781 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3782 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3783 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3784 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3785 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3786 &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]3787</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3788
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3789</div>
3790
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3791<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3792<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3793Instruction</a> </div>
3794<div class="doc_text">
3795
3796<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797<pre>
3798 &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]3799</pre>
3800
3801<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3803 operand shifted to the right a specified number of bits with sign
3804 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3805
3806<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3807<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3808 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3809 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3810
3811<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3812<p>This instruction always performs an arithmetic shift right operation, The
3813 most significant bits of the result will be filled with the sign bit
3814 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3815 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3816 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3817 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3818
3819<h5>Example:</h5>
3820<pre>
3821 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3822 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3823 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3824 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3825 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3826 &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]3827</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3829</div>
3830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3831<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3832<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3833Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3834
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3835<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3836
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3837<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3838<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3839 &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]3840</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3842<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3843<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3844 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3845
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3851<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3852<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3854<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3855 <tbody>
3856 <tr>
3857 <td>In0</td>
3858 <td>In1</td>
3859 <td>Out</td>
3860 </tr>
3861 <tr>
3862 <td>0</td>
3863 <td>0</td>
3864 <td>0</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>1</td>
3869 <td>0</td>
3870 </tr>
3871 <tr>
3872 <td>1</td>
3873 <td>0</td>
3874 <td>0</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>1</td>
3879 <td>1</td>
3880 </tr>
3881 </tbody>
3882</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3885<pre>
3886 &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]3887 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3888 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3889</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3890</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3892<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894<div class="doc_text">
3895
3896<h5>Syntax:</h5>
3897<pre>
3898 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3899</pre>
3900
3901<h5>Overview:</h5>
3902<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3903 two operands.</p>
3904
3905<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3906<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3908 values. Both arguments must have identical types.</p>
3909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3910<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3911<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3913<table border="1" cellspacing="0" cellpadding="4">
3914 <tbody>
3915 <tr>
3916 <td>In0</td>
3917 <td>In1</td>
3918 <td>Out</td>
3919 </tr>
3920 <tr>
3921 <td>0</td>
3922 <td>0</td>
3923 <td>0</td>
3924 </tr>
3925 <tr>
3926 <td>0</td>
3927 <td>1</td>
3928 <td>1</td>
3929 </tr>
3930 <tr>
3931 <td>1</td>
3932 <td>0</td>
3933 <td>1</td>
3934 </tr>
3935 <tr>
3936 <td>1</td>
3937 <td>1</td>
3938 <td>1</td>
3939 </tr>
3940 </tbody>
3941</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3943<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944<pre>
3945 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3946 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3947 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3948</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3950</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3952<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3953<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3954Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3956<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3958<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959<pre>
3960 &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]3961</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3963<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3965 its two operands. The <tt>xor</tt> is used to implement the "one's
3966 complement" operation, which is the "~" operator in C.</p>
3967
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3968<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3969<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3970 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3971 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3974<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3975
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3976<table border="1" cellspacing="0" cellpadding="4">
3977 <tbody>
3978 <tr>
3979 <td>In0</td>
3980 <td>In1</td>
3981 <td>Out</td>
3982 </tr>
3983 <tr>
3984 <td>0</td>
3985 <td>0</td>
3986 <td>0</td>
3987 </tr>
3988 <tr>
3989 <td>0</td>
3990 <td>1</td>
3991 <td>1</td>
3992 </tr>
3993 <tr>
3994 <td>1</td>
3995 <td>0</td>
3996 <td>1</td>
3997 </tr>
3998 <tr>
3999 <td>1</td>
4000 <td>1</td>
4001 <td>0</td>
4002 </tr>
4003 </tbody>
4004</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4006<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007<pre>
4008 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4009 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4010 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4011 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4012</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4013
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4014</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4015
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4016<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4017<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4018 <a name="vectorops">Vector Operations</a>
4019</div>
4020
4021<div class="doc_text">
4022
4023<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024 target-independent manner. These instructions cover the element-access and
4025 vector-specific operations needed to process vectors effectively. While LLVM
4026 does directly support these vector operations, many sophisticated algorithms
4027 will want to use target-specific intrinsics to take full advantage of a
4028 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4029
4030</div>
4031
4032<!-- _______________________________________________________________________ -->
4033<div class="doc_subsubsection">
4034 <a name="i_extractelement">'<tt>extractelement</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>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4041 &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]4042</pre>
4043
4044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4046 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4047
4048
4049<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4050<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4051 of <a href="#t_vector">vector</a> type. The second operand is an index
4052 indicating the position from which to extract the element. The index may be
4053 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 scalar of the same type as the element type of
4057 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4058 <tt>val</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; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4067
4068<!-- _______________________________________________________________________ -->
4069<div class="doc_subsubsection">
4070 <a name="i_insertelement">'<tt>insertelement</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>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4077 &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]4078</pre>
4079
4080<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4082 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4083
4084<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4086 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4087 whose type must equal the element type of the first operand. The third
4088 operand is an index indicating the position at which to insert the value.
4089 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4090
4091<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4092<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4093 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4094 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4095 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4096
4097<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4098<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4099 &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]4100</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4101
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4102</div>
4103
4104<!-- _______________________________________________________________________ -->
4105<div class="doc_subsubsection">
4106 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4107</div>
4108
4109<div class="doc_text">
4110
4111<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4112<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4113 &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]4114</pre>
4115
4116<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4117<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4118 from two input vectors, returning a vector with the same element type as the
4119 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4120
4121<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4122<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4123 with types that match each other. The third argument is a shuffle mask whose
4124 element type is always 'i32'. The result of the instruction is a vector
4125 whose length is the same as the shuffle mask and whose element type is the
4126 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4127
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128<p>The shuffle mask operand is required to be a constant vector with either
4129 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4130
4131<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4132<p>The elements of the two input vectors are numbered from left to right across
4133 both of the vectors. The shuffle mask operand specifies, for each element of
4134 the result vector, which element of the two input vectors the result element
4135 gets. The element selector may be undef (meaning "don't care") and the
4136 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4137
4138<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4139<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4140 &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]4141 &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]4142 &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]4143 &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]4144 &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]4145 &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]4146 &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]4147 &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]4148</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4150</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4151
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4152<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4153<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4154 <a name="aggregateops">Aggregate Operations</a>
4155</div>
4156
4157<div class="doc_text">
4158
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4159<p>LLVM supports several instructions for working with
4160 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161
4162</div>
4163
4164<!-- _______________________________________________________________________ -->
4165<div class="doc_subsubsection">
4166 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4167</div>
4168
4169<div class="doc_text">
4170
4171<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4172<pre>
4173 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4174</pre>
4175
4176<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4177<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4178 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4179
4180<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4181<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4182 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4183 <a href="#t_array">array</a> type. The operands are constant indices to
4184 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4186
4187<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188<p>The result is the value at the position in the aggregate specified by the
4189 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4190
4191<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4192<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4193 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4194</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4195
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4196</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<!-- _______________________________________________________________________ -->
4199<div class="doc_subsubsection">
4200 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4201</div>
4202
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4206<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4207 &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]4208</pre>
4209
4210<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4211<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4212 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4213
4214<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4215<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4216 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4217 <a href="#t_array">array</a> type. The second operand is a first-class
4218 value to insert. The following operands are constant indices indicating
4219 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]4220 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4221 value to insert must have the same type as the value identified by the
4222 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4223
4224<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4225<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4226 that of <tt>val</tt> except that the value at the position specified by the
4227 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4228
4229<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4230<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4231 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4232 %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]4233</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4234
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4235</div>
4236
4237
4238<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4239<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4240 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4241</div>
4242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4243<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4244
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245<p>A key design point of an SSA-based representation is how it represents
4246 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4247 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4249
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4250</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4252<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4253<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4254 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4255</div>
4256
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4257<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4258
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4259<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4260<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4261 &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]4262</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4265<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266 currently executing function, to be automatically released when this function
4267 returns to its caller. The object is always allocated in the generic address
4268 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4269
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4270<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271<p>The '<tt>alloca</tt>' instruction
4272 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4273 runtime stack, returning a pointer of the appropriate type to the program.
4274 If "NumElements" is specified, it is the number of elements allocated,
4275 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4276 specified, the value result of the allocation is guaranteed to be aligned to
4277 at least that boundary. If not specified, or if zero, the target can choose
4278 to align the allocation on any convenient boundary compatible with the
4279 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4280
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4281<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4283<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4284<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4285 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4286 memory is automatically released when the function returns. The
4287 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4288 variables that must have an address available. When the function returns
4289 (either with the <tt><a href="#i_ret">ret</a></tt>
4290 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4291 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4292
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4293<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4294<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4295 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4296 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4297 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4298 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4299</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4301</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4302
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4303<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4304<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4305Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4307<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4309<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4311 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4312 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4313 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314</pre>
4315
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4316<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4317<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4319<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4321 from which to load. The pointer must point to
4322 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4323 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4324 number or order of execution of this <tt>load</tt> with other <a
4325 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4326
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4327<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4328 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]4329 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330 alignment for the target. It is the responsibility of the code emitter to
4331 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4332 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333 produce less efficient code. An alignment of 1 is always safe.</p>
4334
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4335<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4336 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4337 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4338 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4339 and code generator that this load is not expected to be reused in the cache.
4340 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4341 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4342
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4343<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344<p>The location of memory pointed to is loaded. If the value being loaded is of
4345 scalar type then the number of bytes read does not exceed the minimum number
4346 of bytes needed to hold all bits of the type. For example, loading an
4347 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4348 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4349 is undefined if the value was not originally written using a store of the
4350 same type.</p>
4351
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4352<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353<pre>
4354 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4355 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4356 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4357</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4359</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4361<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4362<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4363Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4364
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4365<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4367<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4369 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4370 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4371</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4372
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4373<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4374<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4375
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4376<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4378 and an address at which to store it. The type of the
4379 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4380 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4381 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4382 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4383 order of execution of this <tt>store</tt> with other <a
4384 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4385
4386<p>The optional constant "align" argument specifies the alignment of the
4387 operation (that is, the alignment of the memory address). A value of 0 or an
4388 omitted "align" argument means that the operation has the preferential
4389 alignment for the target. It is the responsibility of the code emitter to
4390 ensure that the alignment information is correct. Overestimating the
4391 alignment results in an undefined behavior. Underestimating the alignment may
4392 produce less efficient code. An alignment of 1 is always safe.</p>
4393
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4394<p>The optional !nontemporal metadata must reference a single metatadata
4395 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4396 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4397 instruction tells the optimizer and code generator that this load is
4398 not expected to be reused in the cache. The code generator may
4399 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4400 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4401
4402
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4403<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4404<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4405 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4406 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4407 does not exceed the minimum number of bytes needed to hold all bits of the
4408 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4409 writing a value of a type like <tt>i20</tt> with a size that is not an
4410 integral number of bytes, it is unspecified what happens to the extra bits
4411 that do not belong to the type, but they will typically be overwritten.</p>
4412
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4413<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4414<pre>
4415 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4416 store i32 3, i32* %ptr <i>; yields {void}</i>
4417 %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]4418</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4419
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4420</div>
4421
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4422<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4423<div class="doc_subsubsection">
4424 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4425</div>
4426
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4427<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4428
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4429<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4430<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4431 &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]4432 &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]4433</pre>
4434
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4435<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4437 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4438 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4439
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4441<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4442 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443 elements of the aggregate object are indexed. The interpretation of each
4444 index is dependent on the type being indexed into. The first index always
4445 indexes the pointer value given as the first argument, the second index
4446 indexes a value of the type pointed to (not necessarily the value directly
4447 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4448 indexed into must be a pointer value, subsequent types can be arrays,
4449 vectors, structs and unions. Note that subsequent types being indexed into
4450 can never be pointers, since that would require loading the pointer before
4451 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4452
4453<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]4454 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4455 integer <b>constants</b> are allowed. When indexing into an array, pointer
4456 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]4457 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4458
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4459<p>For example, let's consider a C code fragment and how it gets compiled to
4460 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4461
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4462<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4463<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4464struct RT {
4465 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4466 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4467 char C;
4468};
4469struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4470 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4471 double Y;
4472 struct RT Z;
4473};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4474
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4475int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4476 return &amp;s[1].Z.B[5][13];
4477}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4478</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4479</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4481<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4482
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4483<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4484<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4485%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4486%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4487
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4488define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4489entry:
4490 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4491 ret i32* %reg
4492}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4493</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4494</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4495
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4496<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4497<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]4498 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4499 }</tt>' type, a structure. The second index indexes into the third element
4500 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4501 i8 }</tt>' type, another structure. The third index indexes into the second
4502 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4503 array. The two dimensions of the array are subscripted into, yielding an
4504 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4505 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4506
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4507<p>Note that it is perfectly legal to index partially through a structure,
4508 returning a pointer to an inner element. Because of this, the LLVM code for
4509 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4510
4511<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4512 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4513 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4514 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4515 %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]4516 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4517 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4518 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4519 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4520</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4521
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4522<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4523 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4524 base pointer is not an <i>in bounds</i> address of an allocated object,
4525 or if any of the addresses that would be formed by successive addition of
4526 the offsets implied by the indices to the base address with infinitely
4527 precise arithmetic are not an <i>in bounds</i> address of that allocated
4528 object. The <i>in bounds</i> addresses for an allocated object are all
4529 the addresses that point into the object, plus the address one byte past
4530 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4531
4532<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4533 the base address with silently-wrapping two's complement arithmetic, and
4534 the result value of the <tt>getelementptr</tt> may be outside the object
4535 pointed to by the base pointer. The result value may not necessarily be
4536 used to access memory though, even if it happens to point into allocated
4537 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4538 section for more information.</p>
4539
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540<p>The getelementptr instruction is often confusing. For some more insight into
4541 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4542
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4543<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4544<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4545 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4546 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4547 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4548 %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]4549 <i>; yields i8*:eptr</i>
4550 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4551 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4552 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4553</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4554
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4555</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4557<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4558<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4559</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4561<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4562
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4563<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564 which all take a single operand and a type. They perform various bit
4565 conversions on the operand.</p>
4566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4567</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4568
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4569<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4570<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4571 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4572</div>
4573<div class="doc_text">
4574
4575<h5>Syntax:</h5>
4576<pre>
4577 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4578</pre>
4579
4580<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4582 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4583
4584<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4586 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4587 size and type of the result, which must be
4588 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4589 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4590 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4591
4592<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4593<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4594 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4595 source size must be larger than the destination size, <tt>trunc</tt> cannot
4596 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4597
4598<h5>Example:</h5>
4599<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4600 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4601 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4602 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4604
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4605</div>
4606
4607<!-- _______________________________________________________________________ -->
4608<div class="doc_subsubsection">
4609 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4610</div>
4611<div class="doc_text">
4612
4613<h5>Syntax:</h5>
4614<pre>
4615 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4616</pre>
4617
4618<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4619<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4620 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4621
4622
4623<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4624<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]4625 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4626 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]4627 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
4631<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]4632 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4633
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4634<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]4635
4636<h5>Example:</h5>
4637<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4638 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4639 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4641
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4642</div>
4643
4644<!-- _______________________________________________________________________ -->
4645<div class="doc_subsubsection">
4646 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4647</div>
4648<div class="doc_text">
4649
4650<h5>Syntax:</h5>
4651<pre>
4652 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4653</pre>
4654
4655<h5>Overview:</h5>
4656<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4657
4658<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4659<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]4660 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4661 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]4662 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4664
4665<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4667 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4668 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4669
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4670<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]4671
4672<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4673<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4674 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4675 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4676</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4678</div>
4679
4680<!-- _______________________________________________________________________ -->
4681<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4682 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4683</div>
4684
4685<div class="doc_text">
4686
4687<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4688<pre>
4689 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4690</pre>
4691
4692<h5>Overview:</h5>
4693<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4694 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4695
4696<h5>Arguments:</h5>
4697<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4698 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4699 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]4700 <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]4701 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4702
4703<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4704<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4705 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> type. If the value cannot fit
4707 within the destination type, <tt>ty2</tt>, then the results are
4708 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4709
4710<h5>Example:</h5>
4711<pre>
4712 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4713 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4714</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4716</div>
4717
4718<!-- _______________________________________________________________________ -->
4719<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4720 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4721</div>
4722<div class="doc_text">
4723
4724<h5>Syntax:</h5>
4725<pre>
4726 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4727</pre>
4728
4729<h5>Overview:</h5>
4730<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]4731 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4732
4733<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4734<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4735 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4736 a <a href="#t_floating">floating point</a> type to cast it to. The source
4737 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4740<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> type to a larger
4742 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4743 used to make a <i>no-op cast</i> because it always changes bits. Use
4744 <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]4745
4746<h5>Example:</h5>
4747<pre>
4748 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4749 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4750</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4751
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
4755<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4756 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4757</div>
4758<div class="doc_text">
4759
4760<h5>Syntax:</h5>
4761<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4762 &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]4763</pre>
4764
4765<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4766<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4768
4769<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4770<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4771 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4772 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4773 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4774 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4775
4776<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4777<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4779 towards zero) unsigned integer value. If the value cannot fit
4780 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4781
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4782<h5>Example:</h5>
4783<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4784 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4785 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4786 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4787</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4788
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4789</div>
4790
4791<!-- _______________________________________________________________________ -->
4792<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4793 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4794</div>
4795<div class="doc_text">
4796
4797<h5>Syntax:</h5>
4798<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4799 &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]4800</pre>
4801
4802<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4803<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4804 <a href="#t_floating">floating point</a> <tt>value</tt> to
4805 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4806
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4807<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4808<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4809 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4810 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4811 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4812 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4813
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4814<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4815<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4816 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4817 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4818 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4819
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4820<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4821<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4822 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4823 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4824 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4826
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4827</div>
4828
4829<!-- _______________________________________________________________________ -->
4830<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4831 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4832</div>
4833<div class="doc_text">
4834
4835<h5>Syntax:</h5>
4836<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4837 &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]4838</pre>
4839
4840<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4841<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4843
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4844<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4845<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]4846 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4847 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4848 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4849 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4850
4851<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4852<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853 integer quantity and converts it to the corresponding floating point
4854 value. If the value cannot fit in the floating point value, the results are
4855 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4856
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4857<h5>Example:</h5>
4858<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4859 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4860 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4861</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4867 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4868</div>
4869<div class="doc_text">
4870
4871<h5>Syntax:</h5>
4872<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4873 &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]4874</pre>
4875
4876<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4877<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4878 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4879
4880<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4881<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]4882 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4883 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4884 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4885 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4886
4887<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4889 quantity and converts it to the corresponding floating point value. If the
4890 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4891
4892<h5>Example:</h5>
4893<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4894 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4895 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4896</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4897
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4898</div>
4899
4900<!-- _______________________________________________________________________ -->
4901<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4902 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4903</div>
4904<div class="doc_text">
4905
4906<h5>Syntax:</h5>
4907<pre>
4908 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4909</pre>
4910
4911<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4912<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4913 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4914
4915<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4916<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4917 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4918 <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]4919
4920<h5>Semantics:</h5>
4921<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4922 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4923 truncating or zero extending that value to the size of the integer type. If
4924 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4925 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4926 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4927 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4928
4929<h5>Example:</h5>
4930<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4931 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4932 %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]4933</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4934
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4935</div>
4936
4937<!-- _______________________________________________________________________ -->
4938<div class="doc_subsubsection">
4939 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4940</div>
4941<div class="doc_text">
4942
4943<h5>Syntax:</h5>
4944<pre>
4945 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4946</pre>
4947
4948<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4949<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4950 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4951
4952<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4953<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4954 value to cast, and a type to cast it to, which must be a
4955 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4956
4957<h5>Semantics:</h5>
4958<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4959 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4960 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4961 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4962 than the size of a pointer then a zero extension is done. If they are the
4963 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4964
4965<h5>Example:</h5>
4966<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4967 %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]4968 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4969 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4972</div>
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4976 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4977</div>
4978<div class="doc_text">
4979
4980<h5>Syntax:</h5>
4981<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4982 &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]4983</pre>
4984
4985<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4986<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4987 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4988
4989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4990<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4991 non-aggregate first class value, and a type to cast it to, which must also be
4992 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4993 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4994 identical. If the source type is a pointer, the destination type must also be
4995 a pointer. This instruction supports bitwise conversion of vectors to
4996 integers and to vectors of other types (as long as they have the same
4997 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4998
4999<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5000<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5001 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5002 this conversion. The conversion is done as if the <tt>value</tt> had been
5003 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5004 be converted to other pointer types with this instruction. To convert
5005 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5006 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5007
5008<h5>Example:</h5>
5009<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5010 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5011 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5012 %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]5013</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5014
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5015</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5016
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5017<!-- ======================================================================= -->
5018<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5020<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021
5022<p>The instructions in this category are the "miscellaneous" instructions, which
5023 defy better classification.</p>
5024
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5025</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5026
5027<!-- _______________________________________________________________________ -->
5028<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5029</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5031<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5032
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5033<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5034<pre>
5035 &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]5036</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5038<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5039<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5040 boolean values based on comparison of its two integer, integer vector, or
5041 pointer operands.</p>
5042
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5043<h5>Arguments:</h5>
5044<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045 the condition code indicating the kind of comparison to perform. It is not a
5046 value, just a keyword. The possible condition code are:</p>
5047
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5048<ol>
5049 <li><tt>eq</tt>: equal</li>
5050 <li><tt>ne</tt>: not equal </li>
5051 <li><tt>ugt</tt>: unsigned greater than</li>
5052 <li><tt>uge</tt>: unsigned greater or equal</li>
5053 <li><tt>ult</tt>: unsigned less than</li>
5054 <li><tt>ule</tt>: unsigned less or equal</li>
5055 <li><tt>sgt</tt>: signed greater than</li>
5056 <li><tt>sge</tt>: signed greater or equal</li>
5057 <li><tt>slt</tt>: signed less than</li>
5058 <li><tt>sle</tt>: signed less or equal</li>
5059</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5060
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5061<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5062 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5063 typed. They must also be identical types.</p>
5064
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5065<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5067 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5068 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]5069 result, as follows:</p>
5070
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5071<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5072 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073 <tt>false</tt> otherwise. No sign interpretation is necessary or
5074 performed.</li>
5075
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5076 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5077 <tt>false</tt> otherwise. No sign interpretation is necessary or
5078 performed.</li>
5079
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5080 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5081 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5082
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5083 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5084 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5085 to <tt>op2</tt>.</li>
5086
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5087 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5089
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5090 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5091 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5092
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5093 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5094 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5098 to <tt>op2</tt>.</li>
5099
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5100 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5102
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5103 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104 <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]5105</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5107<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108 values are compared as if they were integers.</p>
5109
5110<p>If the operands are integer vectors, then they are compared element by
5111 element. The result is an <tt>i1</tt> vector with the same number of elements
5112 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5113
5114<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115<pre>
5116 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5117 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5118 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5119 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5120 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5121 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5122</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5123
5124<p>Note that the code generator does not yet support vector types with
5125 the <tt>icmp</tt> instruction.</p>
5126
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5127</div>
5128
5129<!-- _______________________________________________________________________ -->
5130<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5131</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5132
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5135<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136<pre>
5137 &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]5138</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5139
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5140<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5141<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5142 values based on comparison of its operands.</p>
5143
5144<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]5145(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5146
5147<p>If the operands are floating point vectors, then the result type is a vector
5148 of boolean with the same number of elements as the operands being
5149 compared.</p>
5150
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5151<h5>Arguments:</h5>
5152<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5153 the condition code indicating the kind of comparison to perform. It is not a
5154 value, just a keyword. The possible condition code are:</p>
5155
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5156<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5157 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5158 <li><tt>oeq</tt>: ordered and equal</li>
5159 <li><tt>ogt</tt>: ordered and greater than </li>
5160 <li><tt>oge</tt>: ordered and greater than or equal</li>
5161 <li><tt>olt</tt>: ordered and less than </li>
5162 <li><tt>ole</tt>: ordered and less than or equal</li>
5163 <li><tt>one</tt>: ordered and not equal</li>
5164 <li><tt>ord</tt>: ordered (no nans)</li>
5165 <li><tt>ueq</tt>: unordered or equal</li>
5166 <li><tt>ugt</tt>: unordered or greater than </li>
5167 <li><tt>uge</tt>: unordered or greater than or equal</li>
5168 <li><tt>ult</tt>: unordered or less than </li>
5169 <li><tt>ule</tt>: unordered or less than or equal</li>
5170 <li><tt>une</tt>: unordered or not equal</li>
5171 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5172 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5173</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5174
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5175<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5176 <i>unordered</i> means that either operand may be a QNAN.</p>
5177
5178<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5179 a <a href="#t_floating">floating point</a> type or
5180 a <a href="#t_vector">vector</a> of floating point type. They must have
5181 identical types.</p>
5182
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5183<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5184<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5185 according to the condition code given as <tt>cond</tt>. If the operands are
5186 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5187 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5188 follows:</p>
5189
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5190<ol>
5191 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5192
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5195
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5198
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5201
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5204
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5205 <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]5206 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5207
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5210
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5211 <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]5212
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5213 <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]5214 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5215
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5216 <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]5217 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5218
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5221
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5224
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5227
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5228 <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]5229 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5230
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5231 <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]5232
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5233 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5234</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5235
5236<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5237<pre>
5238 &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]5239 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5240 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5241 &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]5242</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5243
5244<p>Note that the code generator does not yet support vector types with
5245 the <tt>fcmp</tt> instruction.</p>
5246
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5247</div>
5248
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5249<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5250<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5251 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5252</div>
5253
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5254<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5255
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5256<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5257<pre>
5258 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5259</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5260
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5261<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5262<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5263 SSA graph representing the function.</p>
5264
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5265<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5266<p>The type of the incoming values is specified with the first type field. After
5267 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5268 one pair for each predecessor basic block of the current block. Only values
5269 of <a href="#t_firstclass">first class</a> type may be used as the value
5270 arguments to the PHI node. Only labels may be used as the label
5271 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5272
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5273<p>There must be no non-phi instructions between the start of a basic block and
5274 the PHI instructions: i.e. PHI instructions must be first in a basic
5275 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5276
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5278 occur on the edge from the corresponding predecessor block to the current
5279 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5280 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5281
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5282<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5283<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5284 specified by the pair corresponding to the predecessor basic block that
5285 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5286
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5287<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5288<pre>
5289Loop: ; Infinite loop that counts from 0 on up...
5290 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5291 %nextindvar = add i32 %indvar, 1
5292 br label %Loop
5293</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5294
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5295</div>
5296
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5297<!-- _______________________________________________________________________ -->
5298<div class="doc_subsubsection">
5299 <a name="i_select">'<tt>select</tt>' Instruction</a>
5300</div>
5301
5302<div class="doc_text">
5303
5304<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5305<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5306 &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>
5307
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5308 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5309</pre>
5310
5311<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5312<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5313 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5314
5315
5316<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5317<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5318 values indicating the condition, and two values of the
5319 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5320 vectors and the condition is a scalar, then entire vectors are selected, not
5321 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5322
5323<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5324<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5325 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5327<p>If the condition is a vector of i1, then the value arguments must be vectors
5328 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5329
5330<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5331<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5332 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5333</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5334
5335<p>Note that the code generator does not yet support conditions
5336 with vector type.</p>
5337
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5338</div>
5339
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5340<!-- _______________________________________________________________________ -->
5341<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5342 <a name="i_call">'<tt>call</tt>' Instruction</a>
5343</div>
5344
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5345<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5346
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5347<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5348<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5349 &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]5350</pre>
5351
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5352<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5353<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5354
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5355<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5356<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5357
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5358<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5359 <li>The optional "tail" marker indicates that the callee function does not
5360 access any allocas or varargs in the caller. Note that calls may be
5361 marked "tail" even if they do not occur before
5362 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5363 present, the function call is eligible for tail call optimization,
5364 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5365 optimized into a jump</a>. The code generator may optimize calls marked
5366 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5367 sibling call optimization</a> when the caller and callee have
5368 matching signatures, or 2) forced tail call optimization when the
5369 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5370 <ul>
5371 <li>Caller and callee both have the calling
5372 convention <tt>fastcc</tt>.</li>
5373 <li>The call is in tail position (ret immediately follows call and ret
5374 uses value of call or is void).</li>
5375 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5376 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5377 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5378 constraints are met.</a></li>
5379 </ul>
5380 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5381
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5382 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5383 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5384 defaults to using C calling conventions. The calling convention of the
5385 call must match the calling convention of the target function, or else the
5386 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5387
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5388 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5389 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5390 '<tt>inreg</tt>' attributes are valid here.</li>
5391
5392 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5393 type of the return value. Functions that return no value are marked
5394 <tt><a href="#t_void">void</a></tt>.</li>
5395
5396 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5397 being invoked. The argument types must match the types implied by this
5398 signature. This type can be omitted if the function is not varargs and if
5399 the function type does not return a pointer to a function.</li>
5400
5401 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5402 be invoked. In most cases, this is a direct function invocation, but
5403 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5404 to function value.</li>
5405
5406 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5407 signature argument types and parameter attributes. All arguments must be
5408 of <a href="#t_firstclass">first class</a> type. If the function
5409 signature indicates the function accepts a variable number of arguments,
5410 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5411
5412 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5413 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5414 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5415</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5416
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5417<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5419 a specified function, with its incoming arguments bound to the specified
5420 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5421 function, control flow continues with the instruction after the function
5422 call, and the return value of the function is bound to the result
5423 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5425<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5426<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5427 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5428 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5429 %X = tail call i32 @foo() <i>; yields i32</i>
5430 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5431 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5432
5433 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5434 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5435 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5436 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5437 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5438 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5439</pre>
5440
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5441<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5442standard C99 library as being the C99 library functions, and may perform
5443optimizations or generate code for them under that assumption. This is
5444something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5445freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5447</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5448
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5449<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5450<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5451 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5452</div>
5453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5454<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5455
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5456<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5457<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5458 &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]5459</pre>
5460
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5461<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5462<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463 the "variable argument" area of a function call. It is used to implement the
5464 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5465
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5466<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5467<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5468 argument. It returns a value of the specified argument type and increments
5469 the <tt>va_list</tt> to point to the next argument. The actual type
5470 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5471
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5472<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5474 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5475 to the next argument. For more information, see the variable argument
5476 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5477
5478<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]5479 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5480 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5481
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5482<p><tt>va_arg</tt> is an LLVM instruction instead of
5483 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5484 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5485
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5486<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5487<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5489<p>Note that the code generator does not yet fully support va_arg on many
5490 targets. Also, it does not currently support va_arg with aggregate types on
5491 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5492
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5493</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5494
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5495<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5496<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5497<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5499<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5500
5501<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502 well known names and semantics and are required to follow certain
5503 restrictions. Overall, these intrinsics represent an extension mechanism for
5504 the LLVM language that does not require changing all of the transformations
5505 in LLVM when adding to the language (or the bitcode reader/writer, the
5506 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5507
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5508<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5509 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5510 begin with this prefix. Intrinsic functions must always be external
5511 functions: you cannot define the body of intrinsic functions. Intrinsic
5512 functions may only be used in call or invoke instructions: it is illegal to
5513 take the address of an intrinsic function. Additionally, because intrinsic
5514 functions are part of the LLVM language, it is required if any are added that
5515 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5517<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5518 family of functions that perform the same operation but on different data
5519 types. Because LLVM can represent over 8 million different integer types,
5520 overloading is used commonly to allow an intrinsic function to operate on any
5521 integer type. One or more of the argument types or the result type can be
5522 overloaded to accept any integer type. Argument types may also be defined as
5523 exactly matching a previous argument's type or the result type. This allows
5524 an intrinsic function which accepts multiple arguments, but needs all of them
5525 to be of the same type, to only be overloaded with respect to a single
5526 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5527
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5528<p>Overloaded intrinsics will have the names of its overloaded argument types
5529 encoded into its function name, each preceded by a period. Only those types
5530 which are overloaded result in a name suffix. Arguments whose type is matched
5531 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5532 can take an integer of any width and returns an integer of exactly the same
5533 integer width. This leads to a family of functions such as
5534 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5535 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5536 suffix is required. Because the argument's type is matched against the return
5537 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5538
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5539<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5540 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5541
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5542</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5543
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5544<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5545<div class="doc_subsection">
5546 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5547</div>
5548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5549<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5551<p>Variable argument support is defined in LLVM with
5552 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5553 intrinsic functions. These functions are related to the similarly named
5554 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5555
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5556<p>All of these functions operate on arguments that use a target-specific value
5557 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5558 not define what this type is, so all transformations should be prepared to
5559 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5560
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5561<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]5562 instruction and the variable argument handling intrinsic functions are
5563 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5564
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5565<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5566<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5567define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5568 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5569 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5570 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5571 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5572
5573 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5574 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5575
5576 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5577 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5578 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5579 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5580 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5581
5582 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5583 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5584 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5585}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5586
5587declare void @llvm.va_start(i8*)
5588declare void @llvm.va_copy(i8*, i8*)
5589declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5590</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5591</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5592
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5593</div>
5594
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5595<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5596<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5597 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5598</div>
5599
5600
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5601<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5602
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5603<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5604<pre>
5605 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5606</pre>
5607
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5608<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5609<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5610 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]5611
5612<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5613<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]5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5616<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]5617 macro available in C. In a target-dependent way, it initializes
5618 the <tt>va_list</tt> element to which the argument points, so that the next
5619 call to <tt>va_arg</tt> will produce the first variable argument passed to
5620 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5621 need to know the last argument of the function as the compiler can figure
5622 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5624</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5625
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5626<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5627<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5628 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5629</div>
5630
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5631<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5632
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5633<h5>Syntax:</h5>
5634<pre>
5635 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5636</pre>
5637
5638<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5639<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640 which has been initialized previously
5641 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5642 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5643
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5644<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5645<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]5646
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5648<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]5649 macro available in C. In a target-dependent way, it destroys
5650 the <tt>va_list</tt> element to which the argument points. Calls
5651 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5652 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5653 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5654
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5655</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5656
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5657<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5658<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5659 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5660</div>
5661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5662<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5663
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5664<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5665<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5666 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5667</pre>
5668
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5669<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5670<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5671 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5672
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5673<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5674<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]5675 The second argument is a pointer to a <tt>va_list</tt> element to copy
5676 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5677
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5678<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5679<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]5680 macro available in C. In a target-dependent way, it copies the
5681 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5682 element. This intrinsic is necessary because
5683 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5684 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5686</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5687
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5688<!-- ======================================================================= -->
5689<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5690 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5691</div>
5692
5693<div class="doc_text">
5694
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5695<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5696Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5697intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5698roots on the stack</a>, as well as garbage collector implementations that
5699require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5700barriers. Front-ends for type-safe garbage collected languages should generate
5701these intrinsics to make use of the LLVM garbage collectors. For more details,
5702see <a href="GarbageCollection.html">Accurate Garbage Collection with
5703LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5705<p>The garbage collection intrinsics only operate on objects in the generic
5706 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5707
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5708</div>
5709
5710<!-- _______________________________________________________________________ -->
5711<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5712 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5713</div>
5714
5715<div class="doc_text">
5716
5717<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5719 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5723<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]5724 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5727<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5728 root pointer. The second pointer (which must be either a constant or a
5729 global value address) contains the meta-data to be associated with the
5730 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5733<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]5734 location. At compile-time, the code generator generates information to allow
5735 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5736 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5737 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5738
5739</div>
5740
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5741<!-- _______________________________________________________________________ -->
5742<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5743 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744</div>
5745
5746<div class="doc_text">
5747
5748<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5749<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5750 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5751</pre>
5752
5753<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5754<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5755 locations, allowing garbage collector implementations that require read
5756 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5757
5758<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5759<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]5760 allocated from the garbage collector. The first object is a pointer to the
5761 start of the referenced object, if needed by the language runtime (otherwise
5762 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5763
5764<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5765<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5766 instruction, but may be replaced with substantially more complex code by the
5767 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5768 may only be used in a function which <a href="#gc">specifies a GC
5769 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5770
5771</div>
5772
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5773<!-- _______________________________________________________________________ -->
5774<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5775 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5776</div>
5777
5778<div class="doc_text">
5779
5780<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5781<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5782 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5783</pre>
5784
5785<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5786<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5787 locations, allowing garbage collector implementations that require write
5788 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5789
5790<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5791<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]5792 object to store it to, and the third is the address of the field of Obj to
5793 store to. If the runtime does not require a pointer to the object, Obj may
5794 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5795
5796<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5797<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798 instruction, but may be replaced with substantially more complex code by the
5799 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5800 may only be used in a function which <a href="#gc">specifies a GC
5801 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5802
5803</div>
5804
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5805<!-- ======================================================================= -->
5806<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5807 <a name="int_codegen">Code Generator Intrinsics</a>
5808</div>
5809
5810<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811
5812<p>These intrinsics are provided by LLVM to expose special features that may
5813 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5814
5815</div>
5816
5817<!-- _______________________________________________________________________ -->
5818<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5819 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820</div>
5821
5822<div class="doc_text">
5823
5824<h5>Syntax:</h5>
5825<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5826 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5827</pre>
5828
5829<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5830<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5831 target-specific value indicating the return address of the current function
5832 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5833
5834<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5835<p>The argument to this intrinsic indicates which function to return the address
5836 for. Zero indicates the calling function, one indicates its caller, etc.
5837 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5838
5839<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5840<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5841 indicating the return address of the specified call frame, or zero if it
5842 cannot be identified. The value returned by this intrinsic is likely to be
5843 incorrect or 0 for arguments other than zero, so it should only be used for
5844 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<p>Note that calling this intrinsic does not prevent function inlining or other
5847 aggressive transformations, so the value returned may not be that of the
5848 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5849
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5850</div>
5851
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5852<!-- _______________________________________________________________________ -->
5853<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5854 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5855</div>
5856
5857<div class="doc_text">
5858
5859<h5>Syntax:</h5>
5860<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5861 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5862</pre>
5863
5864<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5866 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5867
5868<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869<p>The argument to this intrinsic indicates which function to return the frame
5870 pointer for. Zero indicates the calling function, one indicates its caller,
5871 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5872
5873<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5874<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5875 indicating the frame address of the specified call frame, or zero if it
5876 cannot be identified. The value returned by this intrinsic is likely to be
5877 incorrect or 0 for arguments other than zero, so it should only be used for
5878 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>Note that calling this intrinsic does not prevent function inlining or other
5881 aggressive transformations, so the value returned may not be that of the
5882 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5883
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5884</div>
5885
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5886<!-- _______________________________________________________________________ -->
5887<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5888 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5889</div>
5890
5891<div class="doc_text">
5892
5893<h5>Syntax:</h5>
5894<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5895 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5896</pre>
5897
5898<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5900 of the function stack, for use
5901 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5902 useful for implementing language features like scoped automatic variable
5903 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5904
5905<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5906<p>This intrinsic returns a opaque pointer value that can be passed
5907 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5908 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5909 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5910 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5911 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5912 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5913
5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5918 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
5924<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5925 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5926</pre>
5927
5928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5930 the function stack to the state it was in when the
5931 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5932 executed. This is useful for implementing language features like scoped
5933 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5934
5935<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5936<p>See the description
5937 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5938
5939</div>
5940
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5941<!-- _______________________________________________________________________ -->
5942<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5943 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5944</div>
5945
5946<div class="doc_text">
5947
5948<h5>Syntax:</h5>
5949<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5950 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]5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5955 insert a prefetch instruction if supported; otherwise, it is a noop.
5956 Prefetches have no effect on the behavior of the program but can change its
5957 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5961 specifier determining if the fetch should be for a read (0) or write (1),
5962 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5963 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5964 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5965
5966<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5967<p>This intrinsic does not modify the behavior of the program. In particular,
5968 prefetches cannot trap and do not produce a value. On targets that support
5969 this intrinsic, the prefetch can provide hints to the processor cache for
5970 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5971
5972</div>
5973
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5974<!-- _______________________________________________________________________ -->
5975<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5976 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5977</div>
5978
5979<div class="doc_text">
5980
5981<h5>Syntax:</h5>
5982<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5983 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5984</pre>
5985
5986<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5987<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5988 Counter (PC) in a region of code to simulators and other tools. The method
5989 is target specific, but it is expected that the marker will use exported
5990 symbols to transmit the PC of the marker. The marker makes no guarantees
5991 that it will remain with any specific instruction after optimizations. It is
5992 possible that the presence of a marker will inhibit optimizations. The
5993 intended use is to be inserted after optimizations to allow correlations of
5994 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5995
5996<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5998
5999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6001 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6002
6003</div>
6004
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6005<!-- _______________________________________________________________________ -->
6006<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6007 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6008</div>
6009
6010<div class="doc_text">
6011
6012<h5>Syntax:</h5>
6013<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6014 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6015</pre>
6016
6017<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6018<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6019 counter register (or similar low latency, high accuracy clocks) on those
6020 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6021 should map to RPCC. As the backing counters overflow quickly (on the order
6022 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6023
6024<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6025<p>When directly supported, reading the cycle counter should not modify any
6026 memory. Implementations are allowed to either return a application specific
6027 value or a system wide value. On backends without support, this is lowered
6028 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6029
6030</div>
6031
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6032<!-- ======================================================================= -->
6033<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6034 <a name="int_libc">Standard C Library Intrinsics</a>
6035</div>
6036
6037<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038
6039<p>LLVM provides intrinsics for a few important standard C library functions.
6040 These intrinsics allow source-language front-ends to pass information about
6041 the alignment of the pointer arguments to the code generator, providing
6042 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6043
6044</div>
6045
6046<!-- _______________________________________________________________________ -->
6047<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6048 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6049</div>
6050
6051<div class="doc_text">
6052
6053<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6054<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]6055 integer bit width and for different address spaces. Not all targets support
6056 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6058<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6059 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]6060 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6061 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]6062 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6063</pre>
6064
6065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6067 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6068
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6069<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6070 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6071 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6072
6073<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6074
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The first argument is a pointer to the destination, the second is a pointer
6076 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6077 number of bytes to copy, the fourth argument is the alignment of the
6078 source and destination locations, and the fifth is a boolean indicating a
6079 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6080
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6081<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]6082 then the caller guarantees that both the source and destination pointers are
6083 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6084
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6085<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6086 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6087 The detailed access behavior is not very cleanly specified and it is unwise
6088 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6089
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6090<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6092<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6093 source location to the destination location, which are not allowed to
6094 overlap. It copies "len" bytes of memory over. If the argument is known to
6095 be aligned to some boundary, this can be specified as the fourth argument,
6096 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6097
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6098</div>
6099
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6100<!-- _______________________________________________________________________ -->
6101<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6102 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6103</div>
6104
6105<div class="doc_text">
6106
6107<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6108<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]6109 width and for different address space. Not all targets support all bit
6110 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6112<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6113 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]6114 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6115 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]6116 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6117</pre>
6118
6119<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6120<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6121 source location to the destination location. It is similar to the
6122 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6123 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6124
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6125<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6126 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6127 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128
6129<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The first argument is a pointer to the destination, the second is a pointer
6132 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6133 number of bytes to copy, the fourth argument is the alignment of the
6134 source and destination locations, and the fifth is a boolean indicating a
6135 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6136
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6137<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]6138 then the caller guarantees that the source and destination pointers are
6139 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6140
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6141<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6142 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6143 The detailed access behavior is not very cleanly specified and it is unwise
6144 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6145
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6146<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6148<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6149 source location to the destination location, which may overlap. It copies
6150 "len" bytes of memory over. If the argument is known to be aligned to some
6151 boundary, this can be specified as the fourth argument, otherwise it should
6152 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6153
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6154</div>
6155
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6156<!-- _______________________________________________________________________ -->
6157<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6158 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6159</div>
6160
6161<div class="doc_text">
6162
6163<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6164<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6165 width and for different address spaces. Not all targets support all bit
6166 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6168<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6169 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6170 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6171 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6172 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6173</pre>
6174
6175<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6176<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6177 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6178
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6179<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6180 intrinsic does not return a value, takes extra alignment/volatile arguments,
6181 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6182
6183<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6184<p>The first argument is a pointer to the destination to fill, the second is the
6185 byte value to fill it with, the third argument is an integer argument
6186 specifying the number of bytes to fill, and the fourth argument is the known
6187 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6188
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6189<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]6190 then the caller guarantees that the destination pointer is aligned to that
6191 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6192
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6193<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6194 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6195 The detailed access behavior is not very cleanly specified and it is unwise
6196 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6197
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6198<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6200 at the destination location. If the argument is known to be aligned to some
6201 boundary, this can be specified as the fourth argument, otherwise it should
6202 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6203
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6204</div>
6205
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6206<!-- _______________________________________________________________________ -->
6207<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6208 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6209</div>
6210
6211<div class="doc_text">
6212
6213<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6214<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6215 floating point or vector of floating point type. Not all targets support all
6216 types however.</p>
6217
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6218<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6219 declare float @llvm.sqrt.f32(float %Val)
6220 declare double @llvm.sqrt.f64(double %Val)
6221 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6222 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6223 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6224</pre>
6225
6226<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6227<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6228 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6229 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6230 behavior for negative numbers other than -0.0 (which allows for better
6231 optimization, because there is no need to worry about errno being
6232 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]6233
6234<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6235<p>The argument and return value are floating point numbers of the same
6236 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6237
6238<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>This function returns the sqrt of the specified operand if it is a
6240 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6241
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6242</div>
6243
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6244<!-- _______________________________________________________________________ -->
6245<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6246 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6247</div>
6248
6249<div class="doc_text">
6250
6251<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6252<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6253 floating point or vector of floating point type. Not all targets support all
6254 types however.</p>
6255
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6256<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6257 declare float @llvm.powi.f32(float %Val, i32 %power)
6258 declare double @llvm.powi.f64(double %Val, i32 %power)
6259 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6260 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6261 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6262</pre>
6263
6264<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6265<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6266 specified (positive or negative) power. The order of evaluation of
6267 multiplications is not defined. When a vector of floating point type is
6268 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6269
6270<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6271<p>The second argument is an integer power, and the first is a value to raise to
6272 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6273
6274<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6275<p>This function returns the first value raised to the second power with an
6276 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6277
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6278</div>
6279
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6280<!-- _______________________________________________________________________ -->
6281<div class="doc_subsubsection">
6282 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6283</div>
6284
6285<div class="doc_text">
6286
6287<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6288<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6289 floating point or vector of floating point type. Not all targets support all
6290 types however.</p>
6291
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6292<pre>
6293 declare float @llvm.sin.f32(float %Val)
6294 declare double @llvm.sin.f64(double %Val)
6295 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6296 declare fp128 @llvm.sin.f128(fp128 %Val)
6297 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6298</pre>
6299
6300<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6302
6303<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6304<p>The argument and return value are floating point numbers of the same
6305 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6308<p>This function returns the sine of the specified operand, returning the same
6309 values as the libm <tt>sin</tt> functions would, and handles error conditions
6310 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6311
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6312</div>
6313
6314<!-- _______________________________________________________________________ -->
6315<div class="doc_subsubsection">
6316 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6317</div>
6318
6319<div class="doc_text">
6320
6321<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6322<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6323 floating point or vector of floating point type. Not all targets support all
6324 types however.</p>
6325
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6326<pre>
6327 declare float @llvm.cos.f32(float %Val)
6328 declare double @llvm.cos.f64(double %Val)
6329 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6330 declare fp128 @llvm.cos.f128(fp128 %Val)
6331 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6332</pre>
6333
6334<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6335<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6336
6337<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6338<p>The argument and return value are floating point numbers of the same
6339 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6340
6341<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6342<p>This function returns the cosine of the specified operand, returning the same
6343 values as the libm <tt>cos</tt> functions would, and handles error conditions
6344 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6345
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6346</div>
6347
6348<!-- _______________________________________________________________________ -->
6349<div class="doc_subsubsection">
6350 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6351</div>
6352
6353<div class="doc_text">
6354
6355<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6356<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6357 floating point or vector of floating point type. Not all targets support all
6358 types however.</p>
6359
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6360<pre>
6361 declare float @llvm.pow.f32(float %Val, float %Power)
6362 declare double @llvm.pow.f64(double %Val, double %Power)
6363 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6364 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6365 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6366</pre>
6367
6368<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6369<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6370 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6371
6372<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6373<p>The second argument is a floating point power, and the first is a value to
6374 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6375
6376<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6377<p>This function returns the first value raised to the second power, returning
6378 the same values as the libm <tt>pow</tt> functions would, and handles error
6379 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6380
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6381</div>
6382
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6383<!-- ======================================================================= -->
6384<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6385 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6386</div>
6387
6388<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6389
6390<p>LLVM provides intrinsics for a few important bit manipulation operations.
6391 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6392
6393</div>
6394
6395<!-- _______________________________________________________________________ -->
6396<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6397 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6398</div>
6399
6400<div class="doc_text">
6401
6402<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6403<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6404 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6405
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6406<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6407 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6408 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6409 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6410</pre>
6411
6412<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6413<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6414 values with an even number of bytes (positive multiple of 16 bits). These
6415 are useful for performing operations on data that is not in the target's
6416 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6417
6418<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6419<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6420 and low byte of the input i16 swapped. Similarly,
6421 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6422 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6423 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6424 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6425 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6426 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6427
6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6432 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6438<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]6439 width. Not all targets support all bit widths however.</p>
6440
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6441<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6442 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6443 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6444 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6445 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6446 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6447</pre>
6448
6449<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6450<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6451 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>The only argument is the value to be counted. The argument may be of any
6455 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6456
6457<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458<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]6459
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6460</div>
6461
6462<!-- _______________________________________________________________________ -->
6463<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6464 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6465</div>
6466
6467<div class="doc_text">
6468
6469<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6471 integer bit width. Not all targets support all bit widths however.</p>
6472
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6473<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6474 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6475 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6476 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6477 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6478 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6479</pre>
6480
6481<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6483 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6484
6485<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6486<p>The only argument is the value to be counted. The argument may be of any
6487 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6488
6489<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6491 zeros in a variable. If the src == 0 then the result is the size in bits of
6492 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6493
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6494</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6495
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6496<!-- _______________________________________________________________________ -->
6497<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6498 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6499</div>
6500
6501<div class="doc_text">
6502
6503<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6505 integer bit width. Not all targets support all bit widths however.</p>
6506
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6507<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6508 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6509 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6510 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6511 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6512 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6513</pre>
6514
6515<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6516<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6517 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6518
6519<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6520<p>The only argument is the value to be counted. The argument may be of any
6521 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6522
6523<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6524<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6525 zeros in a variable. If the src == 0 then the result is the size in bits of
6526 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6527
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6528</div>
6529
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6530<!-- ======================================================================= -->
6531<div class="doc_subsection">
6532 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6533</div>
6534
6535<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6536
6537<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6538
6539</div>
6540
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6541<!-- _______________________________________________________________________ -->
6542<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6543 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6544</div>
6545
6546<div class="doc_text">
6547
6548<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6549<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]6550 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6551
6552<pre>
6553 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6554 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6555 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6556</pre>
6557
6558<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6559<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560 a signed addition of the two arguments, and indicate whether an overflow
6561 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6562
6563<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6564<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]6565 be of integer types of any bit width, but they must have the same bit
6566 width. The second element of the result structure must be of
6567 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6568 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6569
6570<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6571<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6572 a signed addition of the two variables. They return a structure &mdash; the
6573 first element of which is the signed summation, and the second element of
6574 which is a bit specifying if the signed summation resulted in an
6575 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6576
6577<h5>Examples:</h5>
6578<pre>
6579 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6580 %sum = extractvalue {i32, i1} %res, 0
6581 %obit = extractvalue {i32, i1} %res, 1
6582 br i1 %obit, label %overflow, label %normal
6583</pre>
6584
6585</div>
6586
6587<!-- _______________________________________________________________________ -->
6588<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6589 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6590</div>
6591
6592<div class="doc_text">
6593
6594<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6595<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]6596 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6597
6598<pre>
6599 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6600 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6601 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6602</pre>
6603
6604<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6605<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6606 an unsigned addition of the two arguments, and indicate whether a carry
6607 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6608
6609<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6610<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]6611 be of integer types of any bit width, but they must have the same bit
6612 width. The second element of the result structure must be of
6613 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6614 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6615
6616<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6617<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618 an unsigned addition of the two arguments. They return a structure &mdash;
6619 the first element of which is the sum, and the second element of which is a
6620 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621
6622<h5>Examples:</h5>
6623<pre>
6624 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6625 %sum = extractvalue {i32, i1} %res, 0
6626 %obit = extractvalue {i32, i1} %res, 1
6627 br i1 %obit, label %carry, label %normal
6628</pre>
6629
6630</div>
6631
6632<!-- _______________________________________________________________________ -->
6633<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6634 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6635</div>
6636
6637<div class="doc_text">
6638
6639<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6640<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]6641 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6642
6643<pre>
6644 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6645 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6646 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6647</pre>
6648
6649<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6650<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6651 a signed subtraction of the two arguments, and indicate whether an overflow
6652 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6653
6654<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6655<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]6656 be of integer types of any bit width, but they must have the same bit
6657 width. The second element of the result structure must be of
6658 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6659 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6660
6661<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6662<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6663 a signed subtraction of the two arguments. They return a structure &mdash;
6664 the first element of which is the subtraction, and the second element of
6665 which is a bit specifying if the signed subtraction resulted in an
6666 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6667
6668<h5>Examples:</h5>
6669<pre>
6670 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6671 %sum = extractvalue {i32, i1} %res, 0
6672 %obit = extractvalue {i32, i1} %res, 1
6673 br i1 %obit, label %overflow, label %normal
6674</pre>
6675
6676</div>
6677
6678<!-- _______________________________________________________________________ -->
6679<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6680 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6681</div>
6682
6683<div class="doc_text">
6684
6685<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6686<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]6687 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6688
6689<pre>
6690 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6691 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6692 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6693</pre>
6694
6695<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6696<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6697 an unsigned subtraction of the two arguments, and indicate whether an
6698 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6699
6700<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6701<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]6702 be of integer types of any bit width, but they must have the same bit
6703 width. The second element of the result structure must be of
6704 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6705 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6706
6707<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6708<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6709 an unsigned subtraction of the two arguments. They return a structure &mdash;
6710 the first element of which is the subtraction, and the second element of
6711 which is a bit specifying if the unsigned subtraction resulted in an
6712 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6713
6714<h5>Examples:</h5>
6715<pre>
6716 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6717 %sum = extractvalue {i32, i1} %res, 0
6718 %obit = extractvalue {i32, i1} %res, 1
6719 br i1 %obit, label %overflow, label %normal
6720</pre>
6721
6722</div>
6723
6724<!-- _______________________________________________________________________ -->
6725<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6726 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6727</div>
6728
6729<div class="doc_text">
6730
6731<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6732<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]6733 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6734
6735<pre>
6736 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6737 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6738 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6739</pre>
6740
6741<h5>Overview:</h5>
6742
6743<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6744 a signed multiplication of the two arguments, and indicate whether an
6745 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6746
6747<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6748<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]6749 be of integer types of any bit width, but they must have the same bit
6750 width. The second element of the result structure must be of
6751 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6752 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6753
6754<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6755<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6756 a signed multiplication of the two arguments. They return a structure &mdash;
6757 the first element of which is the multiplication, and the second element of
6758 which is a bit specifying if the signed multiplication resulted in an
6759 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6760
6761<h5>Examples:</h5>
6762<pre>
6763 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6764 %sum = extractvalue {i32, i1} %res, 0
6765 %obit = extractvalue {i32, i1} %res, 1
6766 br i1 %obit, label %overflow, label %normal
6767</pre>
6768
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6769</div>
6770
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6771<!-- _______________________________________________________________________ -->
6772<div class="doc_subsubsection">
6773 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6774</div>
6775
6776<div class="doc_text">
6777
6778<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6779<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]6780 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6781
6782<pre>
6783 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6784 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6785 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6786</pre>
6787
6788<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6789<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6790 a unsigned multiplication of the two arguments, and indicate whether an
6791 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6792
6793<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6794<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]6795 be of integer types of any bit width, but they must have the same bit
6796 width. The second element of the result structure must be of
6797 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6798 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6799
6800<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6801<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6802 an unsigned multiplication of the two arguments. They return a structure
6803 &mdash; the first element of which is the multiplication, and the second
6804 element of which is a bit specifying if the unsigned multiplication resulted
6805 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6806
6807<h5>Examples:</h5>
6808<pre>
6809 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6810 %sum = extractvalue {i32, i1} %res, 0
6811 %obit = extractvalue {i32, i1} %res, 1
6812 br i1 %obit, label %overflow, label %normal
6813</pre>
6814
6815</div>
6816
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6817<!-- ======================================================================= -->
6818<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6819 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6820</div>
6821
6822<div class="doc_text">
6823
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6824<p>Half precision floating point is a storage-only format. This means that it is
6825 a dense encoding (in memory) but does not support computation in the
6826 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6827
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6828<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6829 value as an i16, then convert it to float with <a
6830 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6831 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6832 double etc). To store the value back to memory, it is first converted to
6833 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6834 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6835 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6836</div>
6837
6838<!-- _______________________________________________________________________ -->
6839<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6840 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6841</div>
6842
6843<div class="doc_text">
6844
6845<h5>Syntax:</h5>
6846<pre>
6847 declare i16 @llvm.convert.to.fp16(f32 %a)
6848</pre>
6849
6850<h5>Overview:</h5>
6851<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6852 a conversion from single precision floating point format to half precision
6853 floating point format.</p>
6854
6855<h5>Arguments:</h5>
6856<p>The intrinsic function contains single argument - the value to be
6857 converted.</p>
6858
6859<h5>Semantics:</h5>
6860<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6861 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6862 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6863 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6864
6865<h5>Examples:</h5>
6866<pre>
6867 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6868 store i16 %res, i16* @x, align 2
6869</pre>
6870
6871</div>
6872
6873<!-- _______________________________________________________________________ -->
6874<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6875 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6876</div>
6877
6878<div class="doc_text">
6879
6880<h5>Syntax:</h5>
6881<pre>
6882 declare f32 @llvm.convert.from.fp16(i16 %a)
6883</pre>
6884
6885<h5>Overview:</h5>
6886<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6887 a conversion from half precision floating point format to single precision
6888 floating point format.</p>
6889
6890<h5>Arguments:</h5>
6891<p>The intrinsic function contains single argument - the value to be
6892 converted.</p>
6893
6894<h5>Semantics:</h5>
6895<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6896 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6897 precision floating point format. The input half-float value is represented by
6898 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6899
6900<h5>Examples:</h5>
6901<pre>
6902 %a = load i16* @x, align 2
6903 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6904</pre>
6905
6906</div>
6907
6908<!-- ======================================================================= -->
6909<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6910 <a name="int_debugger">Debugger Intrinsics</a>
6911</div>
6912
6913<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6914
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6915<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6916 prefix), are described in
6917 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6918 Level Debugging</a> document.</p>
6919
6920</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6921
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6922<!-- ======================================================================= -->
6923<div class="doc_subsection">
6924 <a name="int_eh">Exception Handling Intrinsics</a>
6925</div>
6926
6927<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6928
6929<p>The LLVM exception handling intrinsics (which all start with
6930 <tt>llvm.eh.</tt> prefix), are described in
6931 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6932 Handling</a> document.</p>
6933
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6934</div>
6935
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6936<!-- ======================================================================= -->
6937<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6938 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6939</div>
6940
6941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6942
6943<p>This intrinsic makes it possible to excise one parameter, marked with
6944 the <tt>nest</tt> attribute, from a function. The result is a callable
6945 function pointer lacking the nest parameter - the caller does not need to
6946 provide a value for it. Instead, the value to use is stored in advance in a
6947 "trampoline", a block of memory usually allocated on the stack, which also
6948 contains code to splice the nest value into the argument list. This is used
6949 to implement the GCC nested function address extension.</p>
6950
6951<p>For example, if the function is
6952 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6953 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6954 follows:</p>
6955
6956<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6957<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6958 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6959 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6960 %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]6961 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6962</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6963</div>
6964
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6965<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6966 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6967
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6968</div>
6969
6970<!-- _______________________________________________________________________ -->
6971<div class="doc_subsubsection">
6972 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6973</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6975<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6977<h5>Syntax:</h5>
6978<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979 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]6980</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6981
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6984 function pointer suitable for executing it.</p>
6985
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6986<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6988 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6989 sufficiently aligned block of memory; this memory is written to by the
6990 intrinsic. Note that the size and the alignment are target-specific - LLVM
6991 currently provides no portable way of determining them, so a front-end that
6992 generates this intrinsic needs to have some target-specific knowledge.
6993 The <tt>func</tt> argument must hold a function bitcast to
6994 an <tt>i8*</tt>.</p>
6995
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6996<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6997<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6998 dependent code, turning it into a function. A pointer to this function is
6999 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7000 function pointer type</a> before being called. The new function's signature
7001 is the same as that of <tt>func</tt> with any arguments marked with
7002 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7003 is allowed, and it must be of pointer type. Calling the new function is
7004 equivalent to calling <tt>func</tt> with the same argument list, but
7005 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7006 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7007 by <tt>tramp</tt> is modified, then the effect of any later call to the
7008 returned function pointer is undefined.</p>
7009
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7010</div>
7011
7012<!-- ======================================================================= -->
7013<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7014 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7015</div>
7016
7017<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7019<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7020 hardware constructs for atomic operations and memory synchronization. This
7021 provides an interface to the hardware, not an interface to the programmer. It
7022 is aimed at a low enough level to allow any programming models or APIs
7023 (Application Programming Interfaces) which need atomic behaviors to map
7024 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7025 hardware provides a "universal IR" for source languages, it also provides a
7026 starting point for developing a "universal" atomic operation and
7027 synchronization IR.</p>
7028
7029<p>These do <em>not</em> form an API such as high-level threading libraries,
7030 software transaction memory systems, atomic primitives, and intrinsic
7031 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7032 application libraries. The hardware interface provided by LLVM should allow
7033 a clean implementation of all of these APIs and parallel programming models.
7034 No one model or paradigm should be selected above others unless the hardware
7035 itself ubiquitously does so.</p>
7036
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7037</div>
7038
7039<!-- _______________________________________________________________________ -->
7040<div class="doc_subsubsection">
7041 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7042</div>
7043<div class="doc_text">
7044<h5>Syntax:</h5>
7045<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7046 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]7047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7048
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7049<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7051 specific pairs of memory access types.</p>
7052
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7053<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7054<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7055 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7056 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7057 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7059<ul>
7060 <li><tt>ll</tt>: load-load barrier</li>
7061 <li><tt>ls</tt>: load-store barrier</li>
7062 <li><tt>sl</tt>: store-load barrier</li>
7063 <li><tt>ss</tt>: store-store barrier</li>
7064 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7065</ul>
7066
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7067<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7068<p>This intrinsic causes the system to enforce some ordering constraints upon
7069 the loads and stores of the program. This barrier does not
7070 indicate <em>when</em> any events will occur, it only enforces
7071 an <em>order</em> in which they occur. For any of the specified pairs of load
7072 and store operations (f.ex. load-load, or store-load), all of the first
7073 operations preceding the barrier will complete before any of the second
7074 operations succeeding the barrier begin. Specifically the semantics for each
7075 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7076
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7077<ul>
7078 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7079 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7080 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7082 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7083 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7084 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7085 load after the barrier begins.</li>
7086</ul>
7087
7088<p>These semantics are applied with a logical "and" behavior when more than one
7089 is enabled in a single memory barrier intrinsic.</p>
7090
7091<p>Backends may implement stronger barriers than those requested when they do
7092 not support as fine grained a barrier as requested. Some architectures do
7093 not need all types of barriers and on such architectures, these become
7094 noops.</p>
7095
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7096<h5>Example:</h5>
7097<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7098%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7099%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7100 store i32 4, %ptr
7101
7102%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7103 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7104 <i>; guarantee the above finishes</i>
7105 store i32 8, %ptr <i>; before this begins</i>
7106</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7107
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7108</div>
7109
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7110<!-- _______________________________________________________________________ -->
7111<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7112 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7113</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7114
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7115<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7116
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7117<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7118<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7119 any integer bit width and for different address spaces. Not all targets
7120 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7121
7122<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7123 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7124 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7125 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7126 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]7127</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7128
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130<p>This loads a value in memory and compares it to a given value. If they are
7131 equal, it stores a new value into the memory.</p>
7132
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7135 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7136 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7137 this integer type. While any bit width integer may be used, targets may only
7138 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7140<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7141<p>This entire intrinsic must be executed atomically. It first loads the value
7142 in memory pointed to by <tt>ptr</tt> and compares it with the
7143 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7144 memory. The loaded value is yielded in all cases. This provides the
7145 equivalent of an atomic compare-and-swap operation within the SSA
7146 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7148<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7150%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7151%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7152 store i32 4, %ptr
7153
7154%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7155%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7156 <i>; yields {i32}:result1 = 4</i>
7157%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7158%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7159
7160%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7161%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7162 <i>; yields {i32}:result2 = 8</i>
7163%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7164
7165%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7166</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7168</div>
7169
7170<!-- _______________________________________________________________________ -->
7171<div class="doc_subsubsection">
7172 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7173</div>
7174<div class="doc_text">
7175<h5>Syntax:</h5>
7176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7177<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7178 integer bit width. Not all targets support all bit widths however.</p>
7179
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7181 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7182 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7183 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7184 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]7185</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7186
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7187<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7188<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7189 the value from memory. It then stores the value in <tt>val</tt> in the memory
7190 at <tt>ptr</tt>.</p>
7191
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7192<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7194 the <tt>val</tt> argument and the result must be integers of the same bit
7195 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7196 integer type. The targets may only lower integer representations they
7197 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7198
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7199<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7200<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7201 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7202 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7204<h5>Examples:</h5>
7205<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7206%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7207%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7208 store i32 4, %ptr
7209
7210%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7211%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7212 <i>; yields {i32}:result1 = 4</i>
7213%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7214%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7215
7216%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7217%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7218 <i>; yields {i32}:result2 = 8</i>
7219
7220%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7221%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7222</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7223
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7224</div>
7225
7226<!-- _______________________________________________________________________ -->
7227<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7228 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7229
7230</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7231
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7232<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7233
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7234<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7235<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7236 any integer bit width. Not all targets support all bit widths however.</p>
7237
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7238<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7239 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7240 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7241 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7242 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]7243</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7244
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7245<h5>Overview:</h5>
7246<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7247 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7248
7249<h5>Arguments:</h5>
7250<p>The intrinsic takes two arguments, the first a pointer to an integer value
7251 and the second an integer value. The result is also an integer value. These
7252 integer types can have any bit width, but they must all have the same bit
7253 width. The targets may only lower integer representations they support.</p>
7254
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7255<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256<p>This intrinsic does a series of operations atomically. It first loads the
7257 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7258 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]7259
7260<h5>Examples:</h5>
7261<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7262%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7263%ptr = bitcast i8* %mallocP to i32*
7264 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7265%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7266 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7267%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7268 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7269%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7270 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7271%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7272</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7273
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7274</div>
7275
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7276<!-- _______________________________________________________________________ -->
7277<div class="doc_subsubsection">
7278 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7279
7280</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7282<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7283
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7284<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7285<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7286 any integer bit width and for different address spaces. Not all targets
7287 support all bit widths however.</p>
7288
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7289<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7290 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7291 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7292 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7293 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]7294</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7295
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7296<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7297<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7298 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7299
7300<h5>Arguments:</h5>
7301<p>The intrinsic takes two arguments, the first a pointer to an integer value
7302 and the second an integer value. The result is also an integer value. These
7303 integer types can have any bit width, but they must all have the same bit
7304 width. The targets may only lower integer representations they support.</p>
7305
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7306<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307<p>This intrinsic does a series of operations atomically. It first loads the
7308 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7309 result to <tt>ptr</tt>. It yields the original value stored
7310 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7311
7312<h5>Examples:</h5>
7313<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7314%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7315%ptr = bitcast i8* %mallocP to i32*
7316 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7317%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7319%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7320 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7321%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7322 <i>; yields {i32}:result3 = 2</i>
7323%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7324</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7325
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7326</div>
7327
7328<!-- _______________________________________________________________________ -->
7329<div class="doc_subsubsection">
7330 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7331 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7332 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7333 <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]7334</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7335
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7336<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7339<p>These are overloaded intrinsics. You can
7340 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7341 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7342 bit width and for different address spaces. Not all targets support all bit
7343 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7344
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7345<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7346 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7347 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7348 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7349 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]7350</pre>
7351
7352<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7353 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7354 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7355 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7356 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]7357</pre>
7358
7359<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7360 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7361 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7362 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7363 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]7364</pre>
7365
7366<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7367 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7368 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7369 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7370 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]7371</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7372
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7373<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7374<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7375 the value stored in memory at <tt>ptr</tt>. It yields the original value
7376 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7377
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7378<h5>Arguments:</h5>
7379<p>These intrinsics take two arguments, the first a pointer to an integer value
7380 and the second an integer value. The result is also an integer value. These
7381 integer types can have any bit width, but they must all have the same bit
7382 width. The targets may only lower integer representations they support.</p>
7383
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7384<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7385<p>These intrinsics does a series of operations atomically. They first load the
7386 value stored at <tt>ptr</tt>. They then do the bitwise
7387 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7388 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7389
7390<h5>Examples:</h5>
7391<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7392%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7393%ptr = bitcast i8* %mallocP to i32*
7394 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7395%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7396 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7397%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7398 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7399%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7400 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7401%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7402 <i>; yields {i32}:result3 = FF</i>
7403%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7404</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7405
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7406</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7407
7408<!-- _______________________________________________________________________ -->
7409<div class="doc_subsubsection">
7410 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7411 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7412 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7413 <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]7414</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7415
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7416<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7417
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7418<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7419<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7420 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7421 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7422 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7423
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7424<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7425 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7426 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7427 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7428 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]7429</pre>
7430
7431<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7432 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7433 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7434 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7435 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]7436</pre>
7437
7438<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7439 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7440 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7441 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7442 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]7443</pre>
7444
7445<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7446 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7447 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7448 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7449 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]7450</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7451
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7452<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7453<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7454 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7455 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7457<h5>Arguments:</h5>
7458<p>These intrinsics take two arguments, the first a pointer to an integer value
7459 and the second an integer value. The result is also an integer value. These
7460 integer types can have any bit width, but they must all have the same bit
7461 width. The targets may only lower integer representations they support.</p>
7462
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7463<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7464<p>These intrinsics does a series of operations atomically. They first load the
7465 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7466 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7467 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7468
7469<h5>Examples:</h5>
7470<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7471%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7472%ptr = bitcast i8* %mallocP to i32*
7473 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7474%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7475 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7476%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7477 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7478%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7479 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7480%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7481 <i>; yields {i32}:result3 = 8</i>
7482%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7483</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7484
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7485</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7486
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7487
7488<!-- ======================================================================= -->
7489<div class="doc_subsection">
7490 <a name="int_memorymarkers">Memory Use Markers</a>
7491</div>
7492
7493<div class="doc_text">
7494
7495<p>This class of intrinsics exists to information about the lifetime of memory
7496 objects and ranges where variables are immutable.</p>
7497
7498</div>
7499
7500<!-- _______________________________________________________________________ -->
7501<div class="doc_subsubsection">
7502 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7503</div>
7504
7505<div class="doc_text">
7506
7507<h5>Syntax:</h5>
7508<pre>
7509 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7510</pre>
7511
7512<h5>Overview:</h5>
7513<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7514 object's lifetime.</p>
7515
7516<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7517<p>The first argument is a constant integer representing the size of the
7518 object, or -1 if it is variable sized. The second argument is a pointer to
7519 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7520
7521<h5>Semantics:</h5>
7522<p>This intrinsic indicates that before this point in the code, the value of the
7523 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]7524 never be used and has an undefined value. A load from the pointer that
7525 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7526 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7527
7528</div>
7529
7530<!-- _______________________________________________________________________ -->
7531<div class="doc_subsubsection">
7532 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7533</div>
7534
7535<div class="doc_text">
7536
7537<h5>Syntax:</h5>
7538<pre>
7539 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7540</pre>
7541
7542<h5>Overview:</h5>
7543<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7544 object's lifetime.</p>
7545
7546<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7547<p>The first argument is a constant integer representing the size of the
7548 object, or -1 if it is variable sized. The second argument is a pointer to
7549 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7550
7551<h5>Semantics:</h5>
7552<p>This intrinsic indicates that after this point in the code, the value of the
7553 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7554 never be used and has an undefined value. Any stores into the memory object
7555 following this intrinsic may be removed as dead.
7556
7557</div>
7558
7559<!-- _______________________________________________________________________ -->
7560<div class="doc_subsubsection">
7561 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7562</div>
7563
7564<div class="doc_text">
7565
7566<h5>Syntax:</h5>
7567<pre>
7568 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7569</pre>
7570
7571<h5>Overview:</h5>
7572<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7573 a memory object will not change.</p>
7574
7575<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7576<p>The first argument is a constant integer representing the size of the
7577 object, or -1 if it is variable sized. The second argument is a pointer to
7578 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7579
7580<h5>Semantics:</h5>
7581<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7582 the return value, the referenced memory location is constant and
7583 unchanging.</p>
7584
7585</div>
7586
7587<!-- _______________________________________________________________________ -->
7588<div class="doc_subsubsection">
7589 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7590</div>
7591
7592<div class="doc_text">
7593
7594<h5>Syntax:</h5>
7595<pre>
7596 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7597</pre>
7598
7599<h5>Overview:</h5>
7600<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7601 a memory object are mutable.</p>
7602
7603<h5>Arguments:</h5>
7604<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7605 The second argument is a constant integer representing the size of the
7606 object, or -1 if it is variable sized and the third argument is a pointer
7607 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7608
7609<h5>Semantics:</h5>
7610<p>This intrinsic indicates that the memory is mutable again.</p>
7611
7612</div>
7613
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7614<!-- ======================================================================= -->
7615<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7616 <a name="int_general">General Intrinsics</a>
7617</div>
7618
7619<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7620
7621<p>This class of intrinsics is designed to be generic and has no specific
7622 purpose.</p>
7623
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7624</div>
7625
7626<!-- _______________________________________________________________________ -->
7627<div class="doc_subsubsection">
7628 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7629</div>
7630
7631<div class="doc_text">
7632
7633<h5>Syntax:</h5>
7634<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7635 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]7636</pre>
7637
7638<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7640
7641<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7642<p>The first argument is a pointer to a value, the second is a pointer to a
7643 global string, the third is a pointer to a global string which is the source
7644 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7645
7646<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7647<p>This intrinsic allows annotation of local variables with arbitrary strings.
7648 This can be useful for special purpose optimizations that want to look for
7649 these annotations. These have no other defined use, they are ignored by code
7650 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7651
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7652</div>
7653
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7654<!-- _______________________________________________________________________ -->
7655<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7656 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7657</div>
7658
7659<div class="doc_text">
7660
7661<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7662<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7663 any integer bit width.</p>
7664
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7665<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7666 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7667 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7668 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7669 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7670 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]7671</pre>
7672
7673<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7675
7676<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7677<p>The first argument is an integer value (result of some expression), the
7678 second is a pointer to a global string, the third is a pointer to a global
7679 string which is the source file name, and the last argument is the line
7680 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7681
7682<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683<p>This intrinsic allows annotations to be put on arbitrary expressions with
7684 arbitrary strings. This can be useful for special purpose optimizations that
7685 want to look for these annotations. These have no other defined use, they
7686 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7687
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7688</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7689
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7690<!-- _______________________________________________________________________ -->
7691<div class="doc_subsubsection">
7692 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7693</div>
7694
7695<div class="doc_text">
7696
7697<h5>Syntax:</h5>
7698<pre>
7699 declare void @llvm.trap()
7700</pre>
7701
7702<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7703<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7704
7705<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7707
7708<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7709<p>This intrinsics is lowered to the target dependent trap instruction. If the
7710 target does not have a trap instruction, this intrinsic will be lowered to
7711 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7712
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7713</div>
7714
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7715<!-- _______________________________________________________________________ -->
7716<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7717 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7718</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7719
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7720<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7721
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7722<h5>Syntax:</h5>
7723<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7724 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7725</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7726
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7727<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7728<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7729 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7730 ensure that it is placed on the stack before local variables.</p>
7731
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7732<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7733<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7734 arguments. The first argument is the value loaded from the stack
7735 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7736 that has enough space to hold the value of the guard.</p>
7737
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7738<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7739<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7740 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7741 stack. This is to ensure that if a local variable on the stack is
7742 overwritten, it will destroy the value of the guard. When the function exits,
7743 the guard on the stack is checked against the original guard. If they're
7744 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7745 function.</p>
7746
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7747</div>
7748
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7749<!-- _______________________________________________________________________ -->
7750<div class="doc_subsubsection">
7751 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7752</div>
7753
7754<div class="doc_text">
7755
7756<h5>Syntax:</h5>
7757<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7758 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7759 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7760</pre>
7761
7762<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7763<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7764 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7765 operation like memcpy will either overflow a buffer that corresponds to
7766 an object, or b) to determine that a runtime check for overflow isn't
7767 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7768 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7769
7770<h5>Arguments:</h5>
7771<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7772 argument is a pointer to or into the <tt>object</tt>. The second argument
7773 is a boolean 0 or 1. This argument determines whether you want the
7774 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7775 1, variables are not allowed.</p>
7776
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7777<h5>Semantics:</h5>
7778<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7779 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7780 (depending on the <tt>type</tt> argument if the size cannot be determined
7781 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7782
7783</div>
7784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7785<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7786<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7787<address>
7788 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7790 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7792
7793 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7794 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7795 Last modified: $Date$
7796</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7798</body>
7799</html>