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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 55ae515f9db484125a23429d4906c5edaf9f10d2 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame^]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
65 <li><a href="#t_void">Void Type</a></li>
66 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]67 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]68 </ol>
69 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]70 <li><a href="#t_derived">Derived Types</a>
71 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]72 <li><a href="#t_aggregate">Aggregate Types</a>
73 <ol>
74 <li><a href="#t_array">Array Type</a></li>
75 <li><a href="#t_struct">Structure Type</a></li>
76 <li><a href="#t_pstruct">Packed Structure Type</a></li>
77 <li><a href="#t_union">Union Type</a></li>
78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <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]259 <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]260 </ol>
261 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <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]266 </ol>
267 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
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>
377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%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]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<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]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame^]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<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]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]910<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]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]919<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]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</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><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1133
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1134 <dt><tt><b>inlinehint</b></tt></dt>
1135 <dd>This attribute indicates that the source code contained a hint that inlining
1136 this function is desirable (such as the "inline" keyword in C/C++). It
1137 is just a hint; it imposes no requirements on the inliner.</dd>
1138
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1139 <dt><tt><b>naked</b></tt></dt>
1140 <dd>This attribute disables prologue / epilogue emission for the function.
1141 This can have very system-specific consequences.</dd>
1142
1143 <dt><tt><b>noimplicitfloat</b></tt></dt>
1144 <dd>This attributes disables implicit floating point instructions.</dd>
1145
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1146 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1147 <dd>This attribute indicates that the inliner should never inline this
1148 function in any situation. This attribute may not be used together with
1149 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1150
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1151 <dt><tt><b>noredzone</b></tt></dt>
1152 <dd>This attribute indicates that the code generator should not use a red
1153 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1154
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1155 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1156 <dd>This function attribute indicates that the function never returns
1157 normally. This produces undefined behavior at runtime if the function
1158 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This function attribute indicates that the function never returns with an
1162 unwind or exceptional control flow. If the function does unwind, its
1163 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1164
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>optsize</b></tt></dt>
1166 <dd>This attribute suggests that optimization passes and code generator passes
1167 make choices that keep the code size of this function low, and otherwise
1168 do optimizations specifically to reduce code size.</dd>
1169
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function computes its result (or decides
1172 to unwind an exception) based strictly on its arguments, without
1173 dereferencing any pointer arguments or otherwise accessing any mutable
1174 state (e.g. memory, control registers, etc) visible to caller functions.
1175 It does not write through any pointer arguments
1176 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1177 changes any state visible to callers. This means that it cannot unwind
1178 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1179 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1180
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function does not write through any
1183 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1184 arguments) or otherwise modify any state (e.g. memory, control registers,
1185 etc) visible to caller functions. It may dereference pointer arguments
1186 and read state that may be set in the caller. A readonly function always
1187 returns the same value (or unwinds an exception identically) when called
1188 with the same set of arguments and global state. It cannot unwind an
1189 exception by calling the <tt>C++</tt> exception throwing methods, but may
1190 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1191
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function should emit a stack smashing
1194 protector. It is in the form of a "canary"&mdash;a random value placed on
1195 the stack before the local variables that's checked upon return from the
1196 function to see if it has been overwritten. A heuristic is used to
1197 determine if a function needs stack protectors or not.<br>
1198<br>
1199 If a function that has an <tt>ssp</tt> attribute is inlined into a
1200 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1201 function will have an <tt>ssp</tt> attribute.</dd>
1202
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute indicates that the function should <em>always</em> emit a
1205 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1206 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1207<br>
1208 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1209 function that doesn't have an <tt>sspreq</tt> attribute or which has
1210 an <tt>ssp</tt> attribute, then the resulting function will have
1211 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1212</dl>
1213
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1214</div>
1215
1216<!-- ======================================================================= -->
1217<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1218 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1219</div>
1220
1221<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1222
1223<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1224 the GCC "file scope inline asm" blocks. These blocks are internally
1225 concatenated by LLVM and treated as a single unit, but may be separated in
1226 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1227
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1228<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1229module asm "inline asm code goes here"
1230module asm "more can go here"
1231</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
1233<p>The strings can contain any character by escaping non-printable characters.
1234 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]1235 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1236
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1237<p>The inline asm code is simply printed to the machine code .s file when
1238 assembly code is generated.</p>
1239
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1240</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1241
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
1244 <a name="datalayout">Data Layout</a>
1245</div>
1246
1247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1249<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1250 data is to be laid out in memory. The syntax for the data layout is
1251 simply:</p>
1252
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1253<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1254target datalayout = "<i>layout specification</i>"
1255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1256
1257<p>The <i>layout specification</i> consists of a list of specifications
1258 separated by the minus sign character ('-'). Each specification starts with
1259 a letter and may include other information after the letter to define some
1260 aspect of the data layout. The specifications accepted are as follows:</p>
1261
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1262<dl>
1263 <dt><tt>E</tt></dt>
1264 <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]1265 bits with the most significance have the lowest address location.</dd>
1266
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1267 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1268 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1269 the bits with the least significance have the lowest address
1270 location.</dd>
1271
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1273 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 <i>preferred</i> alignments. All sizes are in bits. Specifying
1275 the <i>pref</i> alignment is optional. If omitted, the
1276 preceding <tt>:</tt> should be omitted too.</dd>
1277
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1278 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1279 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1280 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1283 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1284 <i>size</i>.</dd>
1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1287 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1288 <i>size</i>. Only values of <i>size</i> that are supported by the target
1289 will work. 32 (float) and 64 (double) are supported on all targets;
1290 80 or 128 (different flavors of long double) are also supported on some
1291 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
1296
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1297 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1298 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1299 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1300
1301 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1302 <dd>This specifies a set of native integer widths for the target CPU
1303 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1304 "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]1305 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1306 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1307</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1308
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1309<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1310 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1311 specifications in the <tt>datalayout</tt> keyword. The default specifications
1312 are given in this list:</p>
1313
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1314<ul>
1315 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1316 <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]1317 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1318 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1319 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1320 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1321 <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]1322 alignment of 64-bits</li>
1323 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1324 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1325 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1326 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1327 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1328 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1330
1331<p>When LLVM is determining the alignment for a given type, it uses the
1332 following rules:</p>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334<ol>
1335 <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]1336 specification is used.</li>
1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <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]1339 smallest integer type that is larger than the bitwidth of the sought type
1340 is used. If none of the specifications are larger than the bitwidth then
1341 the the largest integer type is used. For example, given the default
1342 specifications above, the i7 type will use the alignment of i8 (next
1343 largest) while both i65 and i256 will use the alignment of i64 (largest
1344 specified).</li>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346 <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]1347 largest vector type that is smaller than the sought vector type will be
1348 used as a fall back. This happens because &lt;128 x double&gt; can be
1349 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1350</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1351
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1352</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1353
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1354<!-- ======================================================================= -->
1355<div class="doc_subsection">
1356 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1357</div>
1358
1359<div class="doc_text">
1360
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1361<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1362with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1363is undefined. Pointer values are associated with address ranges
1364according to the following rules:</p>
1365
1366<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1367 <li>A pointer value is associated with the addresses associated with
1368 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1369 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1370 range of the variable's storage.</li>
1371 <li>The result value of an allocation instruction is associated with
1372 the address range of the allocated storage.</li>
1373 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1374 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1375 <li>An integer constant other than zero or a pointer value returned
1376 from a function not defined within LLVM may be associated with address
1377 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1378 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1379 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1380</ul>
1381
1382<p>A pointer value is <i>based</i> on another pointer value according
1383 to the following rules:</p>
1384
1385<ul>
1386 <li>A pointer value formed from a
1387 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1388 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1389 <li>The result value of a
1390 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1391 of the <tt>bitcast</tt>.</li>
1392 <li>A pointer value formed by an
1393 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1394 pointer values that contribute (directly or indirectly) to the
1395 computation of the pointer's value.</li>
1396 <li>The "<i>based</i> on" relationship is transitive.</li>
1397</ul>
1398
1399<p>Note that this definition of <i>"based"</i> is intentionally
1400 similar to the definition of <i>"based"</i> in C99, though it is
1401 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1402
1403<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1404<tt><a href="#i_load">load</a></tt> merely indicates the size and
1405alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1406interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1407<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1408and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1409
1410<p>Consequently, type-based alias analysis, aka TBAA, aka
1411<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1412LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1413additional information which specialized optimization passes may use
1414to implement type-based alias analysis.</p>
1415
1416</div>
1417
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1418<!-- ======================================================================= -->
1419<div class="doc_subsection">
1420 <a name="volatile">Volatile Memory Accesses</a>
1421</div>
1422
1423<div class="doc_text">
1424
1425<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1426href="#i_store"><tt>store</tt></a>s, and <a
1427href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1428The optimizers must not change the number of volatile operations or change their
1429order of execution relative to other volatile operations. The optimizers
1430<i>may</i> change the order of volatile operations relative to non-volatile
1431operations. This is not Java's "volatile" and has no cross-thread
1432synchronization behavior.</p>
1433
1434</div>
1435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1436<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1438<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1442<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1443 intermediate representation. Being typed enables a number of optimizations
1444 to be performed on the intermediate representation directly, without having
1445 to do extra analyses on the side before the transformation. A strong type
1446 system makes it easier to read the generated code and enables novel analyses
1447 and transformations that are not feasible to perform on normal three address
1448 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1449
1450</div>
1451
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1452<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1453<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1455
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1456<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1457
1458<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1459
1460<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1462 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1464 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1465 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1466 </tr>
1467 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468 <td><a href="#t_floating">floating point</a></td>
1469 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1470 </tr>
1471 <tr>
1472 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1473 <td><a href="#t_integer">integer</a>,
1474 <a href="#t_floating">floating point</a>,
1475 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1476 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1477 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1478 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1479 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1480 <a href="#t_label">label</a>,
1481 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1482 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1483 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484 <tr>
1485 <td><a href="#t_primitive">primitive</a></td>
1486 <td><a href="#t_label">label</a>,
1487 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1488 <a href="#t_floating">floating point</a>,
1489 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1490 </tr>
1491 <tr>
1492 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1493 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1494 <a href="#t_function">function</a>,
1495 <a href="#t_pointer">pointer</a>,
1496 <a href="#t_struct">structure</a>,
1497 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1498 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499 <a href="#t_vector">vector</a>,
1500 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1501 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1503 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1504</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1505
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1506<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1507 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1508 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1510</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1511
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1512<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1514
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1515<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1518 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1520</div>
1521
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1522<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1523<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1524
1525<div class="doc_text">
1526
1527<h5>Overview:</h5>
1528<p>The integer type is a very simple type that simply specifies an arbitrary
1529 bit width for the integer type desired. Any bit width from 1 bit to
1530 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1531
1532<h5>Syntax:</h5>
1533<pre>
1534 iN
1535</pre>
1536
1537<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1538 value.</p>
1539
1540<h5>Examples:</h5>
1541<table class="layout">
1542 <tr class="layout">
1543 <td class="left"><tt>i1</tt></td>
1544 <td class="left">a single-bit integer.</td>
1545 </tr>
1546 <tr class="layout">
1547 <td class="left"><tt>i32</tt></td>
1548 <td class="left">a 32-bit integer.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>i1942652</tt></td>
1552 <td class="left">a really big integer of over 1 million bits.</td>
1553 </tr>
1554</table>
1555
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1556</div>
1557
1558<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1559<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1560
1561<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1562
1563<table>
1564 <tbody>
1565 <tr><th>Type</th><th>Description</th></tr>
1566 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1567 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1568 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1569 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1570 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1571 </tbody>
1572</table>
1573
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1574</div>
1575
1576<!-- _______________________________________________________________________ -->
1577<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1578
1579<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1580
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1581<h5>Overview:</h5>
1582<p>The void type does not represent any value and has no size.</p>
1583
1584<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1585<pre>
1586 void
1587</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1588
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1589</div>
1590
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1593
1594<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1595
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1596<h5>Overview:</h5>
1597<p>The label type represents code labels.</p>
1598
1599<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1600<pre>
1601 label
1602</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1603
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1604</div>
1605
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1606<!-- _______________________________________________________________________ -->
1607<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1608
1609<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1611<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1612<p>The metadata type represents embedded metadata. No derived types may be
1613 created from metadata except for <a href="#t_function">function</a>
1614 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1615
1616<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1617<pre>
1618 metadata
1619</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1620
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1621</div>
1622
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1623
1624<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1625<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1626
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1627<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1628
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1629<p>The real power in LLVM comes from the derived types in the system. This is
1630 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1631 useful types. Each of these types contain one or more element types which
1632 may be a primitive type, or another derived type. For example, it is
1633 possible to have a two dimensional array, using an array as the element type
1634 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1635
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1636
1637</div>
1638
1639<!-- _______________________________________________________________________ -->
1640<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1641
1642<div class="doc_text">
1643
1644<p>Aggregate Types are a subset of derived types that can contain multiple
1645 member types. <a href="#t_array">Arrays</a>,
1646 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1647 <a href="#t_union">unions</a> are aggregate types.</p>
1648
1649</div>
1650
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1651<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1652<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1653
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1654<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1656<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1657<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1658 sequentially in memory. The array type requires a size (number of elements)
1659 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1660
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1661<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1662<pre>
1663 [&lt;# elements&gt; x &lt;elementtype&gt;]
1664</pre>
1665
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1666<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1667 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1668
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1669<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1670<table class="layout">
1671 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1672 <td class="left"><tt>[40 x i32]</tt></td>
1673 <td class="left">Array of 40 32-bit integer values.</td>
1674 </tr>
1675 <tr class="layout">
1676 <td class="left"><tt>[41 x i32]</tt></td>
1677 <td class="left">Array of 41 32-bit integer values.</td>
1678 </tr>
1679 <tr class="layout">
1680 <td class="left"><tt>[4 x i8]</tt></td>
1681 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1682 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1683</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1684<p>Here are some examples of multidimensional arrays:</p>
1685<table class="layout">
1686 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1687 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1688 <td class="left">3x4 array of 32-bit integer values.</td>
1689 </tr>
1690 <tr class="layout">
1691 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1692 <td class="left">12x10 array of single precision floating point values.</td>
1693 </tr>
1694 <tr class="layout">
1695 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1696 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1697 </tr>
1698</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1699
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1700<p>There is no restriction on indexing beyond the end of the array implied by
1701 a static type (though there are restrictions on indexing beyond the bounds
1702 of an allocated object in some cases). This means that single-dimension
1703 'variable sized array' addressing can be implemented in LLVM with a zero
1704 length array type. An implementation of 'pascal style arrays' in LLVM could
1705 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1707</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1708
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1709<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1710<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1712<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1715<p>The function type can be thought of as a function signature. It consists of
1716 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]1717 function type is a scalar type, a void type, a struct type, or a union
1718 type. If the return type is a struct type then all struct elements must be
1719 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1722<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1723 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1724</pre>
1725
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1726<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]1727 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1728 which indicates that the function takes a variable number of arguments.
1729 Variable argument functions can access their arguments with
1730 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1731 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1732 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1733
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1735<table class="layout">
1736 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1737 <td class="left"><tt>i32 (i32)</tt></td>
1738 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1740 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1741 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1742 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1743 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1744 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1745 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1746 </td>
1747 </tr><tr class="layout">
1748 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1749 <td class="left">A vararg function that takes at least one
1750 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1751 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1752 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1753 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1754 </tr><tr class="layout">
1755 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1756 <td class="left">A function taking an <tt>i32</tt>, returning a
1757 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1758 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1759 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1765<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1766
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1767<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1768
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1769<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1770<p>The structure type is used to represent a collection of data members together
1771 in memory. The packing of the field types is defined to match the ABI of the
1772 underlying processor. The elements of a structure may be any type that has a
1773 size.</p>
1774
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1775<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1776 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1777 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1778 Structures in registers are accessed using the
1779 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1780 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1782<pre>
1783 { &lt;type list&gt; }
1784</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1789 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1790 <td class="left">A triple of three <tt>i32</tt> values</td>
1791 </tr><tr class="layout">
1792 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1793 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1794 second element is a <a href="#t_pointer">pointer</a> to a
1795 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1796 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1797 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1799
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1800</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1802<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1803<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1804</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1806<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1808<h5>Overview:</h5>
1809<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1810 together in memory. There is no padding between fields. Further, the
1811 alignment of a packed structure is 1 byte. The elements of a packed
1812 structure may be any type that has a size.</p>
1813
1814<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1815 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1816 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1817
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1818<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1819<pre>
1820 &lt; { &lt;type list&gt; } &gt;
1821</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<h5>Examples:</h5>
1824<table class="layout">
1825 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1826 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1827 <td class="left">A triple of three <tt>i32</tt> values</td>
1828 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1829 <td class="left">
1830<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1831 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1832 second element is a <a href="#t_pointer">pointer</a> to a
1833 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1834 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1835 </tr>
1836</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1837
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1838</div>
1839
1840<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1841<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1842
1843<div class="doc_text">
1844
1845<h5>Overview:</h5>
1846<p>A union type describes an object with size and alignment suitable for
1847 an object of any one of a given set of types (also known as an "untagged"
1848 union). It is similar in concept and usage to a
1849 <a href="#t_struct">struct</a>, except that all members of the union
1850 have an offset of zero. The elements of a union may be any type that has a
1851 size. Unions must have at least one member - empty unions are not allowed.
1852 </p>
1853
1854<p>The size of the union as a whole will be the size of its largest member,
1855 and the alignment requirements of the union as a whole will be the largest
1856 alignment requirement of any member.</p>
1857
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1858<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]1859 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1860 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1861 Since all members are at offset zero, the getelementptr instruction does
1862 not affect the address, only the type of the resulting pointer.</p>
1863
1864<h5>Syntax:</h5>
1865<pre>
1866 union { &lt;type list&gt; }
1867</pre>
1868
1869<h5>Examples:</h5>
1870<table class="layout">
1871 <tr class="layout">
1872 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1873 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1874 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1875 </tr><tr class="layout">
1876 <td class="left">
1877 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1878 <td class="left">A union, where the first element is a <tt>float</tt> and the
1879 second element is a <a href="#t_pointer">pointer</a> to a
1880 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1881 an <tt>i32</tt>.</td>
1882 </tr>
1883</table>
1884
1885</div>
1886
1887<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1889
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1890<div class="doc_text">
1891
1892<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1893<p>The pointer type is used to specify memory locations.
1894 Pointers are commonly used to reference objects in memory.</p>
1895
1896<p>Pointer types may have an optional address space attribute defining the
1897 numbered address space where the pointed-to object resides. The default
1898 address space is number zero. The semantics of non-zero address
1899 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1900
1901<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1902 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1903
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1904<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1905<pre>
1906 &lt;type&gt; *
1907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1908
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1909<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1910<table class="layout">
1911 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1912 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1913 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1914 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1915 </tr>
1916 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1917 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1918 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1919 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1920 <tt>i32</tt>.</td>
1921 </tr>
1922 <tr class="layout">
1923 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1924 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1925 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1926 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1927</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1928
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1929</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1930
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1931<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1932<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1934<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1935
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1937<p>A vector type is a simple derived type that represents a vector of elements.
1938 Vector types are used when multiple primitive data are operated in parallel
1939 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1940 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1941 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1942
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1943<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1944<pre>
1945 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1946</pre>
1947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1948<p>The number of elements is a constant integer value; elementtype may be any
1949 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1950
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1951<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1952<table class="layout">
1953 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1954 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1955 <td class="left">Vector of 4 32-bit integer values.</td>
1956 </tr>
1957 <tr class="layout">
1958 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1959 <td class="left">Vector of 8 32-bit floating-point values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1963 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1964 </tr>
1965</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1967</div>
1968
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1969<!-- _______________________________________________________________________ -->
1970<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1971<div class="doc_text">
1972
1973<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1974<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1975 corresponds (for example) to the C notion of a forward declared structure
1976 type. In LLVM, opaque types can eventually be resolved to any type (not just
1977 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978
1979<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1980<pre>
1981 opaque
1982</pre>
1983
1984<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1985<table class="layout">
1986 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1987 <td class="left"><tt>opaque</tt></td>
1988 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1989 </tr>
1990</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1991
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1992</div>
1993
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1994<!-- ======================================================================= -->
1995<div class="doc_subsection">
1996 <a name="t_uprefs">Type Up-references</a>
1997</div>
1998
1999<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2001<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2002<p>An "up reference" allows you to refer to a lexically enclosing type without
2003 requiring it to have a name. For instance, a structure declaration may
2004 contain a pointer to any of the types it is lexically a member of. Example
2005 of up references (with their equivalent as named type declarations)
2006 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2007
2008<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2009 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2010 { \2 }* %y = type { %y }*
2011 \1* %z = type %z*
2012</pre>
2013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2014<p>An up reference is needed by the asmprinter for printing out cyclic types
2015 when there is no declared name for a type in the cycle. Because the
2016 asmprinter does not want to print out an infinite type string, it needs a
2017 syntax to handle recursive types that have no names (all names are optional
2018 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2019
2020<h5>Syntax:</h5>
2021<pre>
2022 \&lt;level&gt;
2023</pre>
2024
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2025<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]2026
2027<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2028<table class="layout">
2029 <tr class="layout">
2030 <td class="left"><tt>\1*</tt></td>
2031 <td class="left">Self-referential pointer.</td>
2032 </tr>
2033 <tr class="layout">
2034 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2035 <td class="left">Recursive structure where the upref refers to the out-most
2036 structure.</td>
2037 </tr>
2038</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2039
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2040</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2041
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2042<!-- *********************************************************************** -->
2043<div class="doc_section"> <a name="constants">Constants</a> </div>
2044<!-- *********************************************************************** -->
2045
2046<div class="doc_text">
2047
2048<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2049 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2050
2051</div>
2052
2053<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2054<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055
2056<div class="doc_text">
2057
2058<dl>
2059 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2060 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2061 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2062
2063 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 <dd>Standard integers (such as '4') are constants of
2065 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2066 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2067
2068 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2069 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2070 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2071 notation (see below). The assembler requires the exact decimal value of a
2072 floating-point constant. For example, the assembler accepts 1.25 but
2073 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2074 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2075
2076 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2077 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2078 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2079</dl>
2080
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2081<p>The one non-intuitive notation for constants is the hexadecimal form of
2082 floating point constants. For example, the form '<tt>double
2083 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2084 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2085 constants are required (and the only time that they are generated by the
2086 disassembler) is when a floating point constant must be emitted but it cannot
2087 be represented as a decimal floating point number in a reasonable number of
2088 digits. For example, NaN's, infinities, and other special values are
2089 represented in their IEEE hexadecimal format so that assembly and disassembly
2090 do not cause any bits to change in the constants.</p>
2091
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2092<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2093 represented using the 16-digit form shown above (which matches the IEEE754
2094 representation for double); float values must, however, be exactly
2095 representable as IEE754 single precision. Hexadecimal format is always used
2096 for long double, and there are three forms of long double. The 80-bit format
2097 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2098 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2099 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2100 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2101 currently supported target uses this format. Long doubles will only work if
2102 they match the long double format on your target. All hexadecimal formats
2103 are big-endian (sign bit at the left).</p>
2104
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2105</div>
2106
2107<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2108<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2109<a name="aggregateconstants"></a> <!-- old anchor -->
2110<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2111</div>
2112
2113<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2114
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2115<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2116 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2117
2118<dl>
2119 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121 type definitions (a comma separated list of elements, surrounded by braces
2122 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2123 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2124 Structure constants must have <a href="#t_struct">structure type</a>, and
2125 the number and types of elements must match those specified by the
2126 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2127
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2128 <dt><b>Union constants</b></dt>
2129 <dd>Union constants are represented with notation similar to a structure with
2130 a single element - that is, a single typed element surrounded
2131 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2132 <a href="#t_union">union type</a> can be initialized with a single-element
2133 struct as long as the type of the struct element matches the type of
2134 one of the union members.</dd>
2135
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2136 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2138 definitions (a comma separated list of elements, surrounded by square
2139 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2140 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2141 the number and types of elements must match those specified by the
2142 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2143
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2144 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2145 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2146 definitions (a comma separated list of elements, surrounded by
2147 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2148 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2149 have <a href="#t_vector">vector type</a>, and the number and types of
2150 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2151
2152 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2153 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2154 value to zero of <em>any</em> type, including scalar and
2155 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2156 This is often used to avoid having to print large zero initializers
2157 (e.g. for large arrays) and is always exactly equivalent to using explicit
2158 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2159
2160 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2161 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2162 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2163 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2164 be interpreted as part of the instruction stream, metadata is a place to
2165 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2166</dl>
2167
2168</div>
2169
2170<!-- ======================================================================= -->
2171<div class="doc_subsection">
2172 <a name="globalconstants">Global Variable and Function Addresses</a>
2173</div>
2174
2175<div class="doc_text">
2176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177<p>The addresses of <a href="#globalvars">global variables</a>
2178 and <a href="#functionstructure">functions</a> are always implicitly valid
2179 (link-time) constants. These constants are explicitly referenced when
2180 the <a href="#identifiers">identifier for the global</a> is used and always
2181 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2182 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2183
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2184<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2185@X = global i32 17
2186@Y = global i32 42
2187@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2188</pre>
2189
2190</div>
2191
2192<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2193<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2194<div class="doc_text">
2195
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2196<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]2197 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2198 Undefined values may be of any type (other than label or void) and be used
2199 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2200
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2201<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2202 program is well defined no matter what value is used. This gives the
2203 compiler more freedom to optimize. Here are some examples of (potentially
2204 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2205
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2206
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2207<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2208 %A = add %X, undef
2209 %B = sub %X, undef
2210 %C = xor %X, undef
2211Safe:
2212 %A = undef
2213 %B = undef
2214 %C = undef
2215</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2216
2217<p>This is safe because all of the output bits are affected by the undef bits.
2218Any output bit can have a zero or one depending on the input bits.</p>
2219
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2220<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2221 %A = or %X, undef
2222 %B = and %X, undef
2223Safe:
2224 %A = -1
2225 %B = 0
2226Unsafe:
2227 %A = undef
2228 %B = undef
2229</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2230
2231<p>These logical operations have bits that are not always affected by the input.
2232For example, if "%X" has a zero bit, then the output of the 'and' operation will
2233always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2234such, 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]2235However, it is safe to assume that all bits of the undef could be 0, and
2236optimize the and to 0. Likewise, it is safe to assume that all the bits of
2237the 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]2238-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2239
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2240<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]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>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2253
2254<p>This set of examples show that undefined select (and conditional branch)
2255conditions can go "either way" but they have to come from one of the two
2256operands. In the %A example, if %X and %Y were both known to have a clear low
2257bit, then %A would have to have a cleared low bit. However, in the %C example,
2258the optimizer is allowed to assume that the undef operand could be the same as
2259%Y, allowing the whole select to be eliminated.</p>
2260
2261
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2262<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2263 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2264
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2265 %B = undef
2266 %C = xor %B, %B
2267
2268 %D = undef
2269 %E = icmp lt %D, 4
2270 %F = icmp gte %D, 4
2271
2272Safe:
2273 %A = undef
2274 %B = undef
2275 %C = undef
2276 %D = undef
2277 %E = undef
2278 %F = undef
2279</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2280
2281<p>This example points out that two undef operands are not necessarily the same.
2282This can be surprising to people (and also matches C semantics) where they
2283assume that "X^X" is always zero, even if X is undef. This isn't true for a
2284number of reasons, but the short answer is that an undef "variable" can
2285arbitrarily change its value over its "live range". This is true because the
2286"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2287logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2288so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2289to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2290would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2291
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2292<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2293 %A = fdiv undef, %X
2294 %B = fdiv %X, undef
2295Safe:
2296 %A = undef
2297b: unreachable
2298</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2299
2300<p>These examples show the crucial difference between an <em>undefined
2301value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2302allowed to have an arbitrary bit-pattern. This means that the %A operation
2303can be constant folded to undef because the undef could be an SNaN, and fdiv is
2304not (currently) defined on SNaN's. However, in the second example, we can make
2305a more aggressive assumption: because the undef is allowed to be an arbitrary
2306value, 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]2307has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2308does not execute at all. This allows us to delete the divide and all code after
2309it: since the undefined operation "can't happen", the optimizer can assume that
2310it occurs in dead code.
2311</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2312
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2313<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2314a: store undef -> %X
2315b: store %X -> undef
2316Safe:
2317a: &lt;deleted&gt;
2318b: unreachable
2319</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2339<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2340 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2341 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2342
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2345<ul>
2346<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2347 their operands.</li>
2348
2349<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2350 to their dynamic predecessor basic block.</li>
2351
2352<li>Function arguments depend on the corresponding actual argument values in
2353 the dynamic callers of their functions.</li>
2354
2355<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2356 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2357 control back to them.</li>
2358
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2359<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2360 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2361 or exception-throwing call instructions that dynamically transfer control
2362 back to them.</li>
2363
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2364<li>Non-volatile loads and stores depend on the most recent stores to all of the
2365 referenced memory addresses, following the order in the IR
2366 (including loads and stores implied by intrinsics such as
2367 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2368
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2369<!-- TODO: In the case of multiple threads, this only applies if the store
2370 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2371
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2372<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2373
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2374<li>An instruction with externally visible side effects depends on the most
2375 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2376 the order in the IR. (This includes
2377 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2378
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2379<li>An instruction <i>control-depends</i> on a
2380 <a href="#terminators">terminator instruction</a>
2381 if the terminator instruction has multiple successors and the instruction
2382 is always executed when control transfers to one of the successors, and
2383 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2384
2385<li>Dependence is transitive.</li>
2386
2387</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2388
2389<p>Whenever a trap value is generated, all values which depend on it evaluate
2390 to trap. If they have side effects, the evoke their side effects as if each
2391 operand with a trap value were undef. If they have externally-visible side
2392 effects, the behavior is undefined.</p>
2393
2394<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2395
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2396<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2397entry:
2398 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2399 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2400 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2401 store i32 0, i32* %trap_yet_again ; undefined behavior
2402
2403 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2404 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2405
2406 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2407
2408 %narrowaddr = bitcast i32* @g to i16*
2409 %wideaddr = bitcast i32* @g to i64*
2410 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2411 %trap4 = load i64* %widaddr ; Returns a trap value.
2412
2413 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2414 %br i1 %cmp, %true, %end ; Branch to either destination.
2415
2416true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2417 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2418 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2419 br label %end
2420
2421end:
2422 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2423 ; Both edges into this PHI are
2424 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2425 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2426
2427 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2428 ; so this is defined (ignoring earlier
2429 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2430</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2431
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2432</div>
2433
2434<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2435<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2436 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2437<div class="doc_text">
2438
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2439<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2440
2441<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2442 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2443 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2444
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2445<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2446 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2447 against null. Pointer equality tests between labels addresses is undefined
2448 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2449 equal to the null pointer. This may also be passed around as an opaque
2450 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2451 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2452 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2453
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2454<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2455 using the value as the operand to an inline assembly, but that is target
2456 specific.
2457 </p>
2458
2459</div>
2460
2461
2462<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2463<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2464</div>
2465
2466<div class="doc_text">
2467
2468<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2469 to be used as constants. Constant expressions may be of
2470 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2471 operation that does not have side effects (e.g. load and call are not
2472 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2473
2474<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2475 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2476 <dd>Truncate a constant to another type. The bit size of CST must be larger
2477 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2478
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2479 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2480 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2481 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2482
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2483 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2484 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2485 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2486
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2487 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2488 <dd>Truncate a floating point constant to another floating point type. The
2489 size of CST must be larger than the size of TYPE. Both types must be
2490 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2491
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2493 <dd>Floating point extend a constant to another type. The size of CST must be
2494 smaller or equal to the size of TYPE. Both types must be floating
2495 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2496
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2497 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector integer type. CST must be of
2500 scalar or vector floating point type. Both CST and TYPE must be scalars,
2501 or vectors of the same number of elements. If the value won't fit in the
2502 integer type, the results are undefined.</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>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector integer type. CST must be of
2507 scalar or vector floating point type. Both CST and TYPE must be scalars,
2508 or vectors of the same number of elements. If the value won't fit in the
2509 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2510
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2512 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2513 constant. TYPE must be a scalar or vector floating point type. CST must be
2514 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2515 vectors of the same number of elements. If the value won't fit in the
2516 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2517
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2519 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520 constant. TYPE must be a scalar or vector floating point type. CST must be
2521 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2522 vectors of the same number of elements. If the value won't fit in the
2523 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2524
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2526 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2528 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2529 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2530
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2531 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2533 type. CST must be of integer type. The CST value is zero extended,
2534 truncated, or unchanged to make it fit in a pointer size. This one is
2535 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2536
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2538 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2539 are the same as those for the <a href="#i_bitcast">bitcast
2540 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2541
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2542 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2543 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2544 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2545 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2546 instruction, the index list may have zero or more indexes, which are
2547 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2548
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2551
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2552 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2553 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2554
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2555 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2556 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2557
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2558 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2559 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2560 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2561
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2562 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2563 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2564 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2565
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2566 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2568 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2569
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2570 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2571 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2572 constants. The index list is interpreted in a similar manner as indices in
2573 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2574 index value must be specified.</dd>
2575
2576 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2577 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2578 constants. The index list is interpreted in a similar manner as indices in
2579 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2580 index value must be specified.</dd>
2581
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2582 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2583 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2584 be any of the <a href="#binaryops">binary</a>
2585 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2586 on operands are the same as those for the corresponding instruction
2587 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2588</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2589
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2590</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2592<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2593<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2594<!-- *********************************************************************** -->
2595
2596<!-- ======================================================================= -->
2597<div class="doc_subsection">
2598<a name="inlineasm">Inline Assembler Expressions</a>
2599</div>
2600
2601<div class="doc_text">
2602
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2603<p>LLVM supports inline assembler expressions (as opposed
2604 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2605 a special value. This value represents the inline assembler as a string
2606 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2607 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2608 expression has side effects, and a flag indicating whether the function
2609 containing the asm needs to align its stack conservatively. An example
2610 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2611
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2612<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2613i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2614</pre>
2615
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2616<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2617 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2618 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2619
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2620<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2621%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]2622</pre>
2623
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2624<p>Inline asms with side effects not visible in the constraint list must be
2625 marked as having side effects. This is done through the use of the
2626 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2627
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2629call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2630</pre>
2631
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2632<p>In some cases inline asms will contain code that will not work unless the
2633 stack is aligned in some way, such as calls or SSE instructions on x86,
2634 yet will not contain code that does that alignment within the asm.
2635 The compiler should make conservative assumptions about what the asm might
2636 contain and should generate its usual stack alignment code in the prologue
2637 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2638
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2639<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2640call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2641</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2642
2643<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2644 first.</p>
2645
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2646<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2647 documented here. Constraints on what can be done (e.g. duplication, moving,
2648 etc need to be documented). This is probably best done by reference to
2649 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2650</div>
2651
2652<div class="doc_subsubsection">
2653<a name="inlineasm_md">Inline Asm Metadata</a>
2654</div>
2655
2656<div class="doc_text">
2657
2658<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2659 attached to it that contains a constant integer. If present, the code
2660 generator will use the integer as the location cookie value when report
2661 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2662 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2663 source code that produced it. For example:</p>
2664
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2665<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2666call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2667...
2668!42 = !{ i32 1234567 }
2669</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2670
2671<p>It is up to the front-end to make sense of the magic numbers it places in the
2672 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2673
2674</div>
2675
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2676<!-- ======================================================================= -->
2677<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2678 Strings</a>
2679</div>
2680
2681<div class="doc_text">
2682
2683<p>LLVM IR allows metadata to be attached to instructions in the program that
2684 can convey extra information about the code to the optimizers and code
2685 generator. One example application of metadata is source-level debug
2686 information. There are two metadata primitives: strings and nodes. All
2687 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2688 preceding exclamation point ('<tt>!</tt>').</p>
2689
2690<p>A metadata string is a string surrounded by double quotes. It can contain
2691 any character by escaping non-printable characters with "\xx" where "xx" is
2692 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2693
2694<p>Metadata nodes are represented with notation similar to structure constants
2695 (a comma separated list of elements, surrounded by braces and preceded by an
2696 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2697 10}</tt>". Metadata nodes can have any values as their operand.</p>
2698
2699<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2700 metadata nodes, which can be looked up in the module symbol table. For
2701 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2702
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2703<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2704 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2705
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2706 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2707 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2708 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2709
2710<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2711 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2712
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2713 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2714 %indvar.next = add i64 %indvar, 1, !dbg !21
2715 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2716</div>
2717
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2718
2719<!-- *********************************************************************** -->
2720<div class="doc_section">
2721 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2722</div>
2723<!-- *********************************************************************** -->
2724
2725<p>LLVM has a number of "magic" global variables that contain data that affect
2726code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2727of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2728section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2729by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2730
2731<!-- ======================================================================= -->
2732<div class="doc_subsection">
2733<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2734</div>
2735
2736<div class="doc_text">
2737
2738<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2739href="#linkage_appending">appending linkage</a>. This array contains a list of
2740pointers to global variables and functions which may optionally have a pointer
2741cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2742
2743<pre>
2744 @X = global i8 4
2745 @Y = global i32 123
2746
2747 @llvm.used = appending global [2 x i8*] [
2748 i8* @X,
2749 i8* bitcast (i32* @Y to i8*)
2750 ], section "llvm.metadata"
2751</pre>
2752
2753<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2754compiler, assembler, and linker are required to treat the symbol as if there is
2755a reference to the global that it cannot see. For example, if a variable has
2756internal linkage and no references other than that from the <tt>@llvm.used</tt>
2757list, it cannot be deleted. This is commonly used to represent references from
2758inline asms and other things the compiler cannot "see", and corresponds to
2759"attribute((used))" in GNU C.</p>
2760
2761<p>On some targets, the code generator must emit a directive to the assembler or
2762object file to prevent the assembler and linker from molesting the symbol.</p>
2763
2764</div>
2765
2766<!-- ======================================================================= -->
2767<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2768<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2769</div>
2770
2771<div class="doc_text">
2772
2773<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2774<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2775touching the symbol. On targets that support it, this allows an intelligent
2776linker to optimize references to the symbol without being impeded as it would be
2777by <tt>@llvm.used</tt>.</p>
2778
2779<p>This is a rare construct that should only be used in rare circumstances, and
2780should not be exposed to source languages.</p>
2781
2782</div>
2783
2784<!-- ======================================================================= -->
2785<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2786<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2787</div>
2788
2789<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2790<pre>
2791%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2792@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2793</pre>
2794<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.
2795</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2796
2797</div>
2798
2799<!-- ======================================================================= -->
2800<div class="doc_subsection">
2801<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2802</div>
2803
2804<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2805<pre>
2806%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2807@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2808</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2809
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2810<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.
2811</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2812
2813</div>
2814
2815
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2816<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2817<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2818<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2820<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2821
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822<p>The LLVM instruction set consists of several different classifications of
2823 instructions: <a href="#terminators">terminator
2824 instructions</a>, <a href="#binaryops">binary instructions</a>,
2825 <a href="#bitwiseops">bitwise binary instructions</a>,
2826 <a href="#memoryops">memory instructions</a>, and
2827 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2832<div class="doc_subsection"> <a name="terminators">Terminator
2833Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2834
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2838 in a program ends with a "Terminator" instruction, which indicates which
2839 block should be executed after the current block is finished. These
2840 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2841 control flow, not values (the one exception being the
2842 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2843
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2844<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2845 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2846 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2847 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2848 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2849 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2850 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2851 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2852
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2853</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2854
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2856<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2857Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2859<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2862<pre>
2863 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2864 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2866
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2869 a value) from a function back to the caller.</p>
2870
2871<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2872 value and then causes control flow, and one that just causes control flow to
2873 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2877 return value. The type of the return value must be a
2878 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2881 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2882 value or a return value with a type that does not match its type, or if it
2883 has a void return type and contains a '<tt>ret</tt>' instruction with a
2884 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2888 the calling function's context. If the caller is a
2889 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2890 instruction after the call. If the caller was an
2891 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2892 the beginning of the "normal" destination block. If the instruction returns
2893 a value, that value shall set the call or invoke instruction's return
2894 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2897<pre>
2898 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2899 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2900 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2901</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2902
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2905<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2909<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2910<pre>
2911 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2916 different basic block in the current function. There are two forms of this
2917 instruction, corresponding to a conditional branch and an unconditional
2918 branch.</p>
2919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2922 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2923 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2924 target.</p>
2925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2927<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2928 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2929 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2930 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2932<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2933<pre>
2934Test:
2935 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2936 br i1 %cond, label %IfEqual, label %IfUnequal
2937IfEqual:
2938 <a href="#i_ret">ret</a> i32 1
2939IfUnequal:
2940 <a href="#i_ret">ret</a> i32 0
2941</pre>
2942
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2943</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2946<div class="doc_subsubsection">
2947 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2948</div>
2949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2950<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2953<pre>
2954 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2955</pre>
2956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2958<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2959 several different places. It is a generalization of the '<tt>br</tt>'
2960 instruction, allowing a branch to occur to one of many possible
2961 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2964<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2966 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2967 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2969<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2970<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2971 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2972 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2973 transferred to the corresponding destination; otherwise, control flow is
2974 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2975
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2976<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2978 <tt>switch</tt> instruction, this instruction may be code generated in
2979 different ways. For example, it could be generated as a series of chained
2980 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2981
2982<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2983<pre>
2984 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2985 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2987
2988 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2989 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990
2991 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2992 switch i32 %val, label %otherwise [ i32 0, label %onzero
2993 i32 1, label %onone
2994 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2997</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2998
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3002 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3003</div>
3004
3005<div class="doc_text">
3006
3007<h5>Syntax:</h5>
3008<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3009 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3010</pre>
3011
3012<h5>Overview:</h5>
3013
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3014<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3015 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3016 "<tt>address</tt>". Address must be derived from a <a
3017 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3018
3019<h5>Arguments:</h5>
3020
3021<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3022 rest of the arguments indicate the full set of possible destinations that the
3023 address may point to. Blocks are allowed to occur multiple times in the
3024 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3025
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3026<p>This destination list is required so that dataflow analysis has an accurate
3027 understanding of the CFG.</p>
3028
3029<h5>Semantics:</h5>
3030
3031<p>Control transfers to the block specified in the address argument. All
3032 possible destination blocks must be listed in the label list, otherwise this
3033 instruction has undefined behavior. This implies that jumps to labels
3034 defined in other functions have undefined behavior as well.</p>
3035
3036<h5>Implementation:</h5>
3037
3038<p>This is typically implemented with a jump through a register.</p>
3039
3040<h5>Example:</h5>
3041<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3042 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3043</pre>
3044
3045</div>
3046
3047
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3048<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049<div class="doc_subsubsection">
3050 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3051</div>
3052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3053<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3054
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3055<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3056<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3057 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]3058 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3059</pre>
3060
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3061<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3062<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063 function, with the possibility of control flow transfer to either the
3064 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3065 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3066 control flow will return to the "normal" label. If the callee (or any
3067 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3068 instruction, control is interrupted and continued at the dynamically nearest
3069 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3072<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3074<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3076 convention</a> the call should use. If none is specified, the call
3077 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3078
3079 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3080 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3081 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3082
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3083 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3084 function value being invoked. In most cases, this is a direct function
3085 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3086 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3087
3088 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3092 signature argument types and parameter attributes. All arguments must be
3093 of <a href="#t_firstclass">first class</a> type. If the function
3094 signature indicates the function accepts a variable number of arguments,
3095 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3102
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3103 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3105 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3106</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<p>This instruction is designed to operate as a standard
3110 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3111 primary difference is that it establishes an association with a label, which
3112 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3113
3114<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3116 exception. Additionally, this is important for implementation of
3117 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3118
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3119<p>For the purposes of the SSA form, the definition of the value returned by the
3120 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3121 block to the "normal" label. If the callee unwinds then no return value is
3122 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3123
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3124<p>Note that the code generator does not yet completely support unwind, and
3125that the invoke/unwind semantics are likely to change in future versions.</p>
3126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3127<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3128<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3129 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3130 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3131 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3132 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3133</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3136
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3138
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3139<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3140Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3141
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3142<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3143
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3144<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3145<pre>
3146 unwind
3147</pre>
3148
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151 at the first callee in the dynamic call stack which used
3152 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3153 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3155<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3156<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157 immediately halt. The dynamic call stack is then searched for the
3158 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3159 Once found, execution continues at the "exceptional" destination block
3160 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3161 instruction in the dynamic call chain, undefined behavior results.</p>
3162
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3163<p>Note that the code generator does not yet completely support unwind, and
3164that the invoke/unwind semantics are likely to change in future versions.</p>
3165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3166</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3167
3168<!-- _______________________________________________________________________ -->
3169
3170<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3171Instruction</a> </div>
3172
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 unreachable
3178</pre>
3179
3180<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182 instruction is used to inform the optimizer that a particular portion of the
3183 code is not reachable. This can be used to indicate that the code after a
3184 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3185
3186<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3187<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3188
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3189</div>
3190
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3191<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3192<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3193
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3194<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195
3196<p>Binary operators are used to do most of the computation in a program. They
3197 require two operands of the same type, execute an operation on them, and
3198 produce a single value. The operands might represent multiple data, as is
3199 the case with the <a href="#t_vector">vector</a> data type. The result value
3200 has the same type as its operands.</p>
3201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3202<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3204</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3206<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3207<div class="doc_subsubsection">
3208 <a name="i_add">'<tt>add</tt>' Instruction</a>
3209</div>
3210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3211<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3213<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3215 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3216 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3217 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3218 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3219</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3222<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3223
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3224<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3225<p>The two arguments to the '<tt>add</tt>' instruction must
3226 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3227 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3228
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3229<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3230<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3231
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232<p>If the sum has unsigned overflow, the result returned is the mathematical
3233 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235<p>Because LLVM integers use a two's complement representation, this instruction
3236 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3237
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3238<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3239 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3240 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3241 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3242 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3247</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3249</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3252<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3253 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3261</pre>
3262
3263<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3264<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3265
3266<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3267<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3269 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3272<p>The value produced is the floating point sum of the two operands.</p>
3273
3274<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3275<pre>
3276 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3277</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<!-- _______________________________________________________________________ -->
3282<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3284</div>
3285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3286<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3288<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3290 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3291 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3292 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3293 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3294</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3297<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3298 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3299
3300<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3301 '<tt>neg</tt>' instruction present in most other intermediate
3302 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3304<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305<p>The two arguments to the '<tt>sub</tt>' instruction must
3306 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3307 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3309<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3310<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3311
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3312<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3313 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3314 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3315
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316<p>Because LLVM integers use a two's complement representation, this instruction
3317 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3319<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3320 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3321 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3322 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3323 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3328 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3329</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3331</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3333<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3334<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3335 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3336</div>
3337
3338<div class="doc_text">
3339
3340<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3341<pre>
3342 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3343</pre>
3344
3345<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3346<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3348
3349<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350 '<tt>fneg</tt>' instruction present in most other intermediate
3351 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3352
3353<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3354<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3356 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the floating point difference of the two operands.</p>
3360
3361<h5>Example:</h5>
3362<pre>
3363 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3364 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3365</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3366
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3367</div>
3368
3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3371 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3372</div>
3373
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3374<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3378 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3379 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3380 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3381 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388<p>The two arguments to the '<tt>mul</tt>' instruction must
3389 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3390 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3392<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3393<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395<p>If the result of the multiplication has unsigned overflow, the result
3396 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3397 width of the result.</p>
3398
3399<p>Because LLVM integers use a two's complement representation, and the result
3400 is the same width as the operands, this instruction returns the correct
3401 result for both signed and unsigned integers. If a full product
3402 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3403 be sign-extended or zero-extended as appropriate to the width of the full
3404 product.</p>
3405
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3406<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3407 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3408 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3409 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3410 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3415</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3416
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3417</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3420<div class="doc_subsubsection">
3421 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3422</div>
3423
3424<div class="doc_text">
3425
3426<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3431<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3433
3434<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3435<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3437 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3438
3439<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3440<p>The value produced is the floating point product of the two operands.</p>
3441
3442<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3445</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3447</div>
3448
3449<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3451</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456<pre>
3457 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3459
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3464<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3466 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3467
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3469<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3471<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3473
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3474<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3479</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3481</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3485</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3491 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3492 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3493</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3497
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3499<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3501 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504<p>The value produced is the signed integer quotient of the two operands rounded
3505 towards zero.</p>
3506
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3507<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3509
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3510<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511 undefined behavior; this is a rare case, but can occur, for example, by doing
3512 a 32-bit division of -2147483648 by -1.</p>
3513
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3514<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3515 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3516 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3517
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3521</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3523</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3527Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3529<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3532<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3533 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3534</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536<h5>Overview:</h5>
3537<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3538
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3540<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3542 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3545<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548<pre>
3549 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3552</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3554<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3555<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3556</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3558<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3565<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3567 division of its two arguments.</p>
3568
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3570<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3572 values. Both arguments must have identical types.</p>
3573
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576 This instruction always performs an unsigned division to get the
3577 remainder.</p>
3578
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3579<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3581
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3582<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3584<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585<pre>
3586 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3587</pre>
3588
3589</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3594</div>
3595
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3600 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3605 division of its two operands. This instruction can also take
3606 <a href="#t_vector">vector</a> versions of the values in which case the
3607 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3608
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3609<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3610<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3612 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3613
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3614<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3615<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3617 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3618 a value. For more information about the difference,
3619 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3620 Math Forum</a>. For a table of how this is implemented in various languages,
3621 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3622 Wikipedia: modulo operation</a>.</p>
3623
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3624<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3626
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3627<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3628 Overflow also leads to undefined behavior; this is a rare case, but can
3629 occur, for example, by taking the remainder of a 32-bit division of
3630 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3631 lets srem be implemented using instructions that return both the result of
3632 the division and the remainder.)</p>
3633
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3634<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3637</pre>
3638
3639</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3641<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3642<div class="doc_subsubsection">
3643 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3644
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3646
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3647<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648<pre>
3649 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3654 its two operands.</p>
3655
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Arguments:</h5>
3657<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3658 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3659 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3660
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<p>This instruction returns the <i>remainder</i> of a division. The remainder
3663 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
3667 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3668</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3669
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3670</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3671
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3672<!-- ======================================================================= -->
3673<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3674Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3675
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3676<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677
3678<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3679 program. They are generally very efficient instructions and can commonly be
3680 strength reduced from other instructions. They require two operands of the
3681 same type, execute an operation on them, and produce a single value. The
3682 resulting value is the same type as its operands.</p>
3683
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3684</div>
3685
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3686<!-- _______________________________________________________________________ -->
3687<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3688Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3690<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3692<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693<pre>
3694 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3696
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3697<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3699 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3703 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3704 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3705
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3708 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3709 is (statically or dynamically) negative or equal to or larger than the number
3710 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3711 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3712 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<h5>Example:</h5>
3715<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3717 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3718 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3719 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3720 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3721</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3723</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3727Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3729<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3730
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3731<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3738 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3741<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3743 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3744
3745<h5>Semantics:</h5>
3746<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3747 significant bits of the result will be filled with zero bits after the shift.
3748 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3749 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3750 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3751 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Example:</h5>
3754<pre>
3755 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3756 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3757 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3758 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3759 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3760 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3761</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3763</div>
3764
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3765<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3766<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3767Instruction</a> </div>
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3773</pre>
3774
3775<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3777 operand shifted to the right a specified number of bits with sign
3778 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3781<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786<p>This instruction always performs an arithmetic shift right operation, The
3787 most significant bits of the result will be filled with the sign bit
3788 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3789 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3790 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3791 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3792
3793<h5>Example:</h5>
3794<pre>
3795 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3796 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3797 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3798 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3799 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3800 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3801</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3803</div>
3804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3805<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3806<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3807Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3808
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3809<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3811<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3812<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3813 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3814</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3815
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3818 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3821<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3822 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3823 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3826<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3828<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3829 <tbody>
3830 <tr>
3831 <td>In0</td>
3832 <td>In1</td>
3833 <td>Out</td>
3834 </tr>
3835 <tr>
3836 <td>0</td>
3837 <td>0</td>
3838 <td>0</td>
3839 </tr>
3840 <tr>
3841 <td>0</td>
3842 <td>1</td>
3843 <td>0</td>
3844 </tr>
3845 <tr>
3846 <td>1</td>
3847 <td>0</td>
3848 <td>0</td>
3849 </tr>
3850 <tr>
3851 <td>1</td>
3852 <td>1</td>
3853 <td>1</td>
3854 </tr>
3855 </tbody>
3856</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3859<pre>
3860 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3861 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3862 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3863</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3864</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3865<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3866<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871<pre>
3872 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3873</pre>
3874
3875<h5>Overview:</h5>
3876<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3877 two operands.</p>
3878
3879<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3880<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3881 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3882 values. Both arguments must have identical types.</p>
3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3885<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3886
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3887<table border="1" cellspacing="0" cellpadding="4">
3888 <tbody>
3889 <tr>
3890 <td>In0</td>
3891 <td>In1</td>
3892 <td>Out</td>
3893 </tr>
3894 <tr>
3895 <td>0</td>
3896 <td>0</td>
3897 <td>0</td>
3898 </tr>
3899 <tr>
3900 <td>0</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 <tr>
3905 <td>1</td>
3906 <td>0</td>
3907 <td>1</td>
3908 </tr>
3909 <tr>
3910 <td>1</td>
3911 <td>1</td>
3912 <td>1</td>
3913 </tr>
3914 </tbody>
3915</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918<pre>
3919 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3920 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3921 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3922</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3924</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3927<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3928Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3929
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3930<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3932<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933<pre>
3934 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3939 its two operands. The <tt>xor</tt> is used to implement the "one's
3940 complement" operation, which is the "~" operator in C.</p>
3941
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3943<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3945 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3948<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3950<table border="1" cellspacing="0" cellpadding="4">
3951 <tbody>
3952 <tr>
3953 <td>In0</td>
3954 <td>In1</td>
3955 <td>Out</td>
3956 </tr>
3957 <tr>
3958 <td>0</td>
3959 <td>0</td>
3960 <td>0</td>
3961 </tr>
3962 <tr>
3963 <td>0</td>
3964 <td>1</td>
3965 <td>1</td>
3966 </tr>
3967 <tr>
3968 <td>1</td>
3969 <td>0</td>
3970 <td>1</td>
3971 </tr>
3972 <tr>
3973 <td>1</td>
3974 <td>1</td>
3975 <td>0</td>
3976 </tr>
3977 </tbody>
3978</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3980<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3983 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3984 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3985 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3986</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3988</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3990<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3991<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3992 <a name="vectorops">Vector Operations</a>
3993</div>
3994
3995<div class="doc_text">
3996
3997<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998 target-independent manner. These instructions cover the element-access and
3999 vector-specific operations needed to process vectors effectively. While LLVM
4000 does directly support these vector operations, many sophisticated algorithms
4001 will want to use target-specific intrinsics to take full advantage of a
4002 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4003
4004</div>
4005
4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection">
4008 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4009</div>
4010
4011<div class="doc_text">
4012
4013<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4014<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4015 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4016</pre>
4017
4018<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4020 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4021
4022
4023<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4025 of <a href="#t_vector">vector</a> type. The second operand is an index
4026 indicating the position from which to extract the element. The index may be
4027 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The result is a scalar of the same type as the element type of
4031 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4032 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4033 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4037 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4038</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4039
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
4044 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4050<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4051 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4052</pre>
4053
4054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4056 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4060 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4061 whose type must equal the element type of the first operand. The third
4062 operand is an index indicating the position at which to insert the value.
4063 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4067 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4068 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4069 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4072<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4073 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4086<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4087 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4088</pre>
4089
4090<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4092 from two input vectors, returning a vector with the same element type as the
4093 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4097 with types that match each other. The third argument is a shuffle mask whose
4098 element type is always 'i32'. The result of the instruction is a vector
4099 whose length is the same as the shuffle mask and whose element type is the
4100 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4101
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4102<p>The shuffle mask operand is required to be a constant vector with either
4103 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4104
4105<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106<p>The elements of the two input vectors are numbered from left to right across
4107 both of the vectors. The shuffle mask operand specifies, for each element of
4108 the result vector, which element of the two input vectors the result element
4109 gets. The element selector may be undef (meaning "don't care") and the
4110 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4111
4112<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4114 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4115 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4116 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4117 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4118 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4119 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4120 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4121 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4122</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4125
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4126<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4127<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4128 <a name="aggregateops">Aggregate Operations</a>
4129</div>
4130
4131<div class="doc_text">
4132
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4133<p>LLVM supports several instructions for working with
4134 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135
4136</div>
4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4141</div>
4142
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4146<pre>
4147 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4151<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4152 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4156 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4157 <a href="#t_array">array</a> type. The operands are constant indices to
4158 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4162<p>The result is the value at the position in the aggregate specified by the
4163 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4166<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4167 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4168</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4169
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection">
4174 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4175</div>
4176
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4180<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4181 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4182</pre>
4183
4184<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4185<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4186 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4187
4188<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4190 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4191 <a href="#t_array">array</a> type. The second operand is a first-class
4192 value to insert. The following operands are constant indices indicating
4193 the position at which to insert the value in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4195 value to insert must have the same type as the value identified by the
4196 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4200 that of <tt>val</tt> except that the value at the position specified by the
4201 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4202
4203<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4204<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4205 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4206 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4207</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4209</div>
4210
4211
4212<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4213<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4214 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4215</div>
4216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4217<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4218
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219<p>A key design point of an SSA-based representation is how it represents
4220 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4221 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4224</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4226<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4227<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4228 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4229</div>
4230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4231<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4234<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4235 &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]4236</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4238<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4239<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240 currently executing function, to be automatically released when this function
4241 returns to its caller. The object is always allocated in the generic address
4242 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>alloca</tt>' instruction
4246 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4247 runtime stack, returning a pointer of the appropriate type to the program.
4248 If "NumElements" is specified, it is the number of elements allocated,
4249 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4250 specified, the value result of the allocation is guaranteed to be aligned to
4251 at least that boundary. If not specified, or if zero, the target can choose
4252 to align the allocation on any convenient boundary compatible with the
4253 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4255<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4257<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4258<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4260 memory is automatically released when the function returns. The
4261 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4262 variables that must have an address available. When the function returns
4263 (either with the <tt><a href="#i_ret">ret</a></tt>
4264 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4265 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4267<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4268<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4269 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4270 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4271 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4272 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4273</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4277<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4278<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4279Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4280
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4281<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4285 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4286 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4287 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288</pre>
4289
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4291<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4295 from which to load. The pointer must point to
4296 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4297 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4298 number or order of execution of this <tt>load</tt> with other <a
4299 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4301<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4303 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304 alignment for the target. It is the responsibility of the code emitter to
4305 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4306 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307 produce less efficient code. An alignment of 1 is always safe.</p>
4308
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4309<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4310 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4311 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4312 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4313 and code generator that this load is not expected to be reused in the cache.
4314 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4315 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4316
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318<p>The location of memory pointed to is loaded. If the value being loaded is of
4319 scalar type then the number of bytes read does not exceed the minimum number
4320 of bytes needed to hold all bits of the type. For example, loading an
4321 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4322 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4323 is undefined if the value was not originally written using a store of the
4324 same type.</p>
4325
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327<pre>
4328 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4329 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4330 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4331</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4332
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4333</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4334
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4335<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4336<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4337Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4339<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4343 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4344 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4345</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4347<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4348<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4352 and an address at which to store it. The type of the
4353 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4354 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4355 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4356 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4357 order of execution of this <tt>store</tt> with other <a
4358 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359
4360<p>The optional constant "align" argument specifies the alignment of the
4361 operation (that is, the alignment of the memory address). A value of 0 or an
4362 omitted "align" argument means that the operation has the preferential
4363 alignment for the target. It is the responsibility of the code emitter to
4364 ensure that the alignment information is correct. Overestimating the
4365 alignment results in an undefined behavior. Underestimating the alignment may
4366 produce less efficient code. An alignment of 1 is always safe.</p>
4367
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4368<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4369 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4370 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4371 instruction tells the optimizer and code generator that this load is
4372 not expected to be reused in the cache. The code generator may
4373 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4374 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4375
4376
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4377<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4378<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4379 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4380 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4381 does not exceed the minimum number of bytes needed to hold all bits of the
4382 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4383 writing a value of a type like <tt>i20</tt> with a size that is not an
4384 integral number of bytes, it is unspecified what happens to the extra bits
4385 that do not belong to the type, but they will typically be overwritten.</p>
4386
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4387<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388<pre>
4389 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4390 store i32 3, i32* %ptr <i>; yields {void}</i>
4391 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4392</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4394</div>
4395
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4396<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4397<div class="doc_subsubsection">
4398 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4399</div>
4400
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4401<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4403<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4404<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4405 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4406 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4407</pre>
4408
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4411 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4412 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4413
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4414<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4415<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4416 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4417 elements of the aggregate object are indexed. The interpretation of each
4418 index is dependent on the type being indexed into. The first index always
4419 indexes the pointer value given as the first argument, the second index
4420 indexes a value of the type pointed to (not necessarily the value directly
4421 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4422 indexed into must be a pointer value, subsequent types can be arrays,
4423 vectors, structs and unions. Note that subsequent types being indexed into
4424 can never be pointers, since that would require loading the pointer before
4425 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4426
4427<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4428 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4429 integer <b>constants</b> are allowed. When indexing into an array, pointer
4430 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4431 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4432
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433<p>For example, let's consider a C code fragment and how it gets compiled to
4434 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4435
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4436<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4437struct RT {
4438 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4439 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4440 char C;
4441};
4442struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4443 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4444 double Y;
4445 struct RT Z;
4446};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4447
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4448int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4449 return &amp;s[1].Z.B[5][13];
4450}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4451</pre>
4452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4453<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4454
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4455<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4456%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4457%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4458
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4459define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4460entry:
4461 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4462 ret i32* %reg
4463}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4464</pre>
4465
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4466<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4467<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]4468 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4469 }</tt>' type, a structure. The second index indexes into the third element
4470 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4471 i8 }</tt>' type, another structure. The third index indexes into the second
4472 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4473 array. The two dimensions of the array are subscripted into, yielding an
4474 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4475 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4477<p>Note that it is perfectly legal to index partially through a structure,
4478 returning a pointer to an inner element. Because of this, the LLVM code for
4479 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4480
4481<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4482 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4483 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4484 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4485 %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]4486 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4487 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4488 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4490</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4491
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4492<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4493 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4494 base pointer is not an <i>in bounds</i> address of an allocated object,
4495 or if any of the addresses that would be formed by successive addition of
4496 the offsets implied by the indices to the base address with infinitely
4497 precise arithmetic are not an <i>in bounds</i> address of that allocated
4498 object. The <i>in bounds</i> addresses for an allocated object are all
4499 the addresses that point into the object, plus the address one byte past
4500 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4501
4502<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4503 the base address with silently-wrapping two's complement arithmetic, and
4504 the result value of the <tt>getelementptr</tt> may be outside the object
4505 pointed to by the base pointer. The result value may not necessarily be
4506 used to access memory though, even if it happens to point into allocated
4507 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4508 section for more information.</p>
4509
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4510<p>The getelementptr instruction is often confusing. For some more insight into
4511 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4512
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4513<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4514<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4515 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4516 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4517 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4518 %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]4519 <i>; yields i8*:eptr</i>
4520 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4521 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4522 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4523</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4524
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4525</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4527<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4528<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4529</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4530
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4531<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4532
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4533<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4534 which all take a single operand and a type. They perform various bit
4535 conversions on the operand.</p>
4536
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4537</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4538
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4539<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4540<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4541 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4542</div>
4543<div class="doc_text">
4544
4545<h5>Syntax:</h5>
4546<pre>
4547 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4548</pre>
4549
4550<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4551<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4552 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4553
4554<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4555<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4556 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4557 size and type of the result, which must be
4558 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4559 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4560 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4561
4562<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4563<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4564 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4565 source size must be larger than the destination size, <tt>trunc</tt> cannot
4566 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4567
4568<h5>Example:</h5>
4569<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4570 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4571 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4572 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4573</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4575</div>
4576
4577<!-- _______________________________________________________________________ -->
4578<div class="doc_subsubsection">
4579 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4580</div>
4581<div class="doc_text">
4582
4583<h5>Syntax:</h5>
4584<pre>
4585 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4586</pre>
4587
4588<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4589<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4590 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4591
4592
4593<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4594<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]4595 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4596 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]4597 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4598 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4599
4600<h5>Semantics:</h5>
4601<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]4602 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4604<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]4605
4606<h5>Example:</h5>
4607<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4608 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4609 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4610</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612</div>
4613
4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
4616 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4617</div>
4618<div class="doc_text">
4619
4620<h5>Syntax:</h5>
4621<pre>
4622 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4623</pre>
4624
4625<h5>Overview:</h5>
4626<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4627
4628<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4629<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]4630 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4631 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]4632 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4633 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4634
4635<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4636<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4637 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4638 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4639
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4640<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]4641
4642<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4643<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4644 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4645 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4646</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4647
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4648</div>
4649
4650<!-- _______________________________________________________________________ -->
4651<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4652 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4653</div>
4654
4655<div class="doc_text">
4656
4657<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4658<pre>
4659 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4660</pre>
4661
4662<h5>Overview:</h5>
4663<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4665
4666<h5>Arguments:</h5>
4667<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4668 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4669 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]4670 <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]4671 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4672
4673<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4675 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4676 <a href="#t_floating">floating point</a> type. If the value cannot fit
4677 within the destination type, <tt>ty2</tt>, then the results are
4678 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4679
4680<h5>Example:</h5>
4681<pre>
4682 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4683 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4684</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4685
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4686</div>
4687
4688<!-- _______________________________________________________________________ -->
4689<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4690 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4691</div>
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
4696 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4697</pre>
4698
4699<h5>Overview:</h5>
4700<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]4701 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4702
4703<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4704<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4706 a <a href="#t_floating">floating point</a> type to cast it to. The source
4707 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4708
4709<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4710<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4711 <a href="#t_floating">floating point</a> type to a larger
4712 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4713 used to make a <i>no-op cast</i> because it always changes bits. Use
4714 <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]4715
4716<h5>Example:</h5>
4717<pre>
4718 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4719 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4720</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4722</div>
4723
4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4726 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4727</div>
4728<div class="doc_text">
4729
4730<h5>Syntax:</h5>
4731<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4732 &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]4733</pre>
4734
4735<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4736<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4737 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4741 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4742 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4743 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4744 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4745
4746<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4747<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4749 towards zero) unsigned integer value. If the value cannot fit
4750 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4751
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4752<h5>Example:</h5>
4753<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4754 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4755 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4756 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4757</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4759</div>
4760
4761<!-- _______________________________________________________________________ -->
4762<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4763 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764</div>
4765<div class="doc_text">
4766
4767<h5>Syntax:</h5>
4768<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4769 &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]4770</pre>
4771
4772<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4773<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4774 <a href="#t_floating">floating point</a> <tt>value</tt> to
4775 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4776
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4777<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4779 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4780 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4781 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4782 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4783
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4784<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4785<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4787 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4788 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4789
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4790<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4791<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4792 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4793 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4794 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4795</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4797</div>
4798
4799<!-- _______________________________________________________________________ -->
4800<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4801 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4802</div>
4803<div class="doc_text">
4804
4805<h5>Syntax:</h5>
4806<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4807 &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]4808</pre>
4809
4810<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4811<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4812 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4813
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4814<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4815<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]4816 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4817 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4818 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4819 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4820
4821<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4822<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4823 integer quantity and converts it to the corresponding floating point
4824 value. If the value cannot fit in the floating point value, the results are
4825 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4826
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4827<h5>Example:</h5>
4828<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4829 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4830 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4831</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4832
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4833</div>
4834
4835<!-- _______________________________________________________________________ -->
4836<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4837 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4838</div>
4839<div class="doc_text">
4840
4841<h5>Syntax:</h5>
4842<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4843 &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]4844</pre>
4845
4846<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4847<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4848 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4849
4850<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4851<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]4852 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4853 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4854 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4855 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4856
4857<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4858<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4859 quantity and converts it to the corresponding floating point value. If the
4860 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4861
4862<h5>Example:</h5>
4863<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4864 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4865 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4866</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4867
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4868</div>
4869
4870<!-- _______________________________________________________________________ -->
4871<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4872 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4873</div>
4874<div class="doc_text">
4875
4876<h5>Syntax:</h5>
4877<pre>
4878 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4879</pre>
4880
4881<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4883 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4884
4885<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4887 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4888 <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]4889
4890<h5>Semantics:</h5>
4891<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4892 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4893 truncating or zero extending that value to the size of the integer type. If
4894 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4895 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4896 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4897 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4898
4899<h5>Example:</h5>
4900<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4901 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4902 %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]4903</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4904
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4905</div>
4906
4907<!-- _______________________________________________________________________ -->
4908<div class="doc_subsubsection">
4909 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4910</div>
4911<div class="doc_text">
4912
4913<h5>Syntax:</h5>
4914<pre>
4915 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4916</pre>
4917
4918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4919<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4920 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4921
4922<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4923<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924 value to cast, and a type to cast it to, which must be a
4925 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4926
4927<h5>Semantics:</h5>
4928<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4929 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4930 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4931 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4932 than the size of a pointer then a zero extension is done. If they are the
4933 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4934
4935<h5>Example:</h5>
4936<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4937 %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]4938 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4939 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4941
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4942</div>
4943
4944<!-- _______________________________________________________________________ -->
4945<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4946 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4947</div>
4948<div class="doc_text">
4949
4950<h5>Syntax:</h5>
4951<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4952 &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]4953</pre>
4954
4955<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4956<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4957 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4958
4959<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4961 non-aggregate first class value, and a type to cast it to, which must also be
4962 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4963 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4964 identical. If the source type is a pointer, the destination type must also be
4965 a pointer. This instruction supports bitwise conversion of vectors to
4966 integers and to vectors of other types (as long as they have the same
4967 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4968
4969<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4970<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4972 this conversion. The conversion is done as if the <tt>value</tt> had been
4973 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4974 be converted to other pointer types with this instruction. To convert
4975 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4976 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4977
4978<h5>Example:</h5>
4979<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4980 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4981 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4982 %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]4983</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4985</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4986
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4987<!-- ======================================================================= -->
4988<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4989
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4990<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4991
4992<p>The instructions in this category are the "miscellaneous" instructions, which
4993 defy better classification.</p>
4994
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4995</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4996
4997<!-- _______________________________________________________________________ -->
4998<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4999</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5000
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5001<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5003<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004<pre>
5005 &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]5006</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5007
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5008<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5009<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5010 boolean values based on comparison of its two integer, integer vector, or
5011 pointer operands.</p>
5012
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5013<h5>Arguments:</h5>
5014<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5015 the condition code indicating the kind of comparison to perform. It is not a
5016 value, just a keyword. The possible condition code are:</p>
5017
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5018<ol>
5019 <li><tt>eq</tt>: equal</li>
5020 <li><tt>ne</tt>: not equal </li>
5021 <li><tt>ugt</tt>: unsigned greater than</li>
5022 <li><tt>uge</tt>: unsigned greater or equal</li>
5023 <li><tt>ult</tt>: unsigned less than</li>
5024 <li><tt>ule</tt>: unsigned less or equal</li>
5025 <li><tt>sgt</tt>: signed greater than</li>
5026 <li><tt>sge</tt>: signed greater or equal</li>
5027 <li><tt>slt</tt>: signed less than</li>
5028 <li><tt>sle</tt>: signed less or equal</li>
5029</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5031<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5032 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5033 typed. They must also be identical types.</p>
5034
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5037 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5038 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]5039 result, as follows:</p>
5040
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5041<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5042 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043 <tt>false</tt> otherwise. No sign interpretation is necessary or
5044 performed.</li>
5045
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5046 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>false</tt> otherwise. No sign interpretation is necessary or
5048 performed.</li>
5049
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5050 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5052
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5053 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5054 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5055 to <tt>op2</tt>.</li>
5056
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5057 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5059
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5060 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5062
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5063 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5064 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5065
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5066 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5067 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5068 to <tt>op2</tt>.</li>
5069
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5072
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5074 <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]5075</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5077<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078 values are compared as if they were integers.</p>
5079
5080<p>If the operands are integer vectors, then they are compared element by
5081 element. The result is an <tt>i1</tt> vector with the same number of elements
5082 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5083
5084<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5085<pre>
5086 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5087 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5088 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5089 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5090 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5091 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5092</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5093
5094<p>Note that the code generator does not yet support vector types with
5095 the <tt>icmp</tt> instruction.</p>
5096
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5097</div>
5098
5099<!-- _______________________________________________________________________ -->
5100<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5101</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5103<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5105<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106<pre>
5107 &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]5108</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5110<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5111<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5112 values based on comparison of its operands.</p>
5113
5114<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]5115(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116
5117<p>If the operands are floating point vectors, then the result type is a vector
5118 of boolean with the same number of elements as the operands being
5119 compared.</p>
5120
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5121<h5>Arguments:</h5>
5122<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5123 the condition code indicating the kind of comparison to perform. It is not a
5124 value, just a keyword. The possible condition code are:</p>
5125
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5126<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5127 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5128 <li><tt>oeq</tt>: ordered and equal</li>
5129 <li><tt>ogt</tt>: ordered and greater than </li>
5130 <li><tt>oge</tt>: ordered and greater than or equal</li>
5131 <li><tt>olt</tt>: ordered and less than </li>
5132 <li><tt>ole</tt>: ordered and less than or equal</li>
5133 <li><tt>one</tt>: ordered and not equal</li>
5134 <li><tt>ord</tt>: ordered (no nans)</li>
5135 <li><tt>ueq</tt>: unordered or equal</li>
5136 <li><tt>ugt</tt>: unordered or greater than </li>
5137 <li><tt>uge</tt>: unordered or greater than or equal</li>
5138 <li><tt>ult</tt>: unordered or less than </li>
5139 <li><tt>ule</tt>: unordered or less than or equal</li>
5140 <li><tt>une</tt>: unordered or not equal</li>
5141 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5142 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5143</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5144
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5145<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5146 <i>unordered</i> means that either operand may be a QNAN.</p>
5147
5148<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5149 a <a href="#t_floating">floating point</a> type or
5150 a <a href="#t_vector">vector</a> of floating point type. They must have
5151 identical types.</p>
5152
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5153<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5154<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5155 according to the condition code given as <tt>cond</tt>. If the operands are
5156 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5157 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158 follows:</p>
5159
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5160<ol>
5161 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5163 <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]5164 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5165
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5166 <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]5167 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5168
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5169 <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]5170 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5171
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5172 <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]5173 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5174
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5175 <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]5176 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5177
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5180
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5181 <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]5182
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5183 <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]5184 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5185
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5186 <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]5187 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5188
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5189 <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]5190 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5191
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5192 <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]5193 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5194
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5195 <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]5196 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5197
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5198 <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]5199 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5200
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5201 <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]5202
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5203 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5204</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5205
5206<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5207<pre>
5208 &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]5209 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5210 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5211 &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]5212</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5213
5214<p>Note that the code generator does not yet support vector types with
5215 the <tt>fcmp</tt> instruction.</p>
5216
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5217</div>
5218
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5219<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5220<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5221 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5222</div>
5223
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5224<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5225
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5227<pre>
5228 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5229</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5231<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5232<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5233 SSA graph representing the function.</p>
5234
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5235<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5236<p>The type of the incoming values is specified with the first type field. After
5237 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5238 one pair for each predecessor basic block of the current block. Only values
5239 of <a href="#t_firstclass">first class</a> type may be used as the value
5240 arguments to the PHI node. Only labels may be used as the label
5241 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5242
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5243<p>There must be no non-phi instructions between the start of a basic block and
5244 the PHI instructions: i.e. PHI instructions must be first in a basic
5245 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5246
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5247<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5248 occur on the edge from the corresponding predecessor block to the current
5249 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5250 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5251
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5252<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5253<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5254 specified by the pair corresponding to the predecessor basic block that
5255 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5256
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5257<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5258<pre>
5259Loop: ; Infinite loop that counts from 0 on up...
5260 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5261 %nextindvar = add i32 %indvar, 1
5262 br label %Loop
5263</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5264
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5265</div>
5266
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5267<!-- _______________________________________________________________________ -->
5268<div class="doc_subsubsection">
5269 <a name="i_select">'<tt>select</tt>' Instruction</a>
5270</div>
5271
5272<div class="doc_text">
5273
5274<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5275<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5276 &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>
5277
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5278 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5279</pre>
5280
5281<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5282<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5283 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5284
5285
5286<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5287<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5288 values indicating the condition, and two values of the
5289 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5290 vectors and the condition is a scalar, then entire vectors are selected, not
5291 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5292
5293<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5294<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5295 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5296
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5297<p>If the condition is a vector of i1, then the value arguments must be vectors
5298 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5299
5300<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5301<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5302 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5303</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5304
5305<p>Note that the code generator does not yet support conditions
5306 with vector type.</p>
5307
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5308</div>
5309
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5310<!-- _______________________________________________________________________ -->
5311<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5312 <a name="i_call">'<tt>call</tt>' Instruction</a>
5313</div>
5314
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5315<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5317<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5318<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5319 &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]5320</pre>
5321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5322<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5323<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5325<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5326<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5327
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5328<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5329 <li>The optional "tail" marker indicates that the callee function does not
5330 access any allocas or varargs in the caller. Note that calls may be
5331 marked "tail" even if they do not occur before
5332 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5333 present, the function call is eligible for tail call optimization,
5334 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5335 optimized into a jump</a>. The code generator may optimize calls marked
5336 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5337 sibling call optimization</a> when the caller and callee have
5338 matching signatures, or 2) forced tail call optimization when the
5339 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5340 <ul>
5341 <li>Caller and callee both have the calling
5342 convention <tt>fastcc</tt>.</li>
5343 <li>The call is in tail position (ret immediately follows call and ret
5344 uses value of call or is void).</li>
5345 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5346 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5347 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5348 constraints are met.</a></li>
5349 </ul>
5350 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5352 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5353 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5354 defaults to using C calling conventions. The calling convention of the
5355 call must match the calling convention of the target function, or else the
5356 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5357
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5358 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5359 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5360 '<tt>inreg</tt>' attributes are valid here.</li>
5361
5362 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5363 type of the return value. Functions that return no value are marked
5364 <tt><a href="#t_void">void</a></tt>.</li>
5365
5366 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5367 being invoked. The argument types must match the types implied by this
5368 signature. This type can be omitted if the function is not varargs and if
5369 the function type does not return a pointer to a function.</li>
5370
5371 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5372 be invoked. In most cases, this is a direct function invocation, but
5373 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5374 to function value.</li>
5375
5376 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5377 signature argument types and parameter attributes. All arguments must be
5378 of <a href="#t_firstclass">first class</a> type. If the function
5379 signature indicates the function accepts a variable number of arguments,
5380 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5381
5382 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5383 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5384 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5385</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5387<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5388<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5389 a specified function, with its incoming arguments bound to the specified
5390 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5391 function, control flow continues with the instruction after the function
5392 call, and the return value of the function is bound to the result
5393 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5395<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5396<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5397 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5398 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5399 %X = tail call i32 @foo() <i>; yields i32</i>
5400 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5401 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5402
5403 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5404 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5405 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5406 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5407 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5408 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5409</pre>
5410
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5411<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5412standard C99 library as being the C99 library functions, and may perform
5413optimizations or generate code for them under that assumption. This is
5414something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5415freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5416
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5417</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5418
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5419<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5420<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5421 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5422</div>
5423
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5424<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5425
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5427<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5428 &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]5429</pre>
5430
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5431<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5432<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5433 the "variable argument" area of a function call. It is used to implement the
5434 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5435
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5436<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5437<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5438 argument. It returns a value of the specified argument type and increments
5439 the <tt>va_list</tt> to point to the next argument. The actual type
5440 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5441
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5442<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5443<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5444 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5445 to the next argument. For more information, see the variable argument
5446 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5447
5448<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]5449 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5450 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5451
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5452<p><tt>va_arg</tt> is an LLVM instruction instead of
5453 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5454 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5455
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5456<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5457<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5458
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5459<p>Note that the code generator does not yet fully support va_arg on many
5460 targets. Also, it does not currently support va_arg with aggregate types on
5461 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5463</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5464
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5465<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5466<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5467<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5469<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5470
5471<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472 well known names and semantics and are required to follow certain
5473 restrictions. Overall, these intrinsics represent an extension mechanism for
5474 the LLVM language that does not require changing all of the transformations
5475 in LLVM when adding to the language (or the bitcode reader/writer, the
5476 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5477
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5478<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5480 begin with this prefix. Intrinsic functions must always be external
5481 functions: you cannot define the body of intrinsic functions. Intrinsic
5482 functions may only be used in call or invoke instructions: it is illegal to
5483 take the address of an intrinsic function. Additionally, because intrinsic
5484 functions are part of the LLVM language, it is required if any are added that
5485 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5487<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5488 family of functions that perform the same operation but on different data
5489 types. Because LLVM can represent over 8 million different integer types,
5490 overloading is used commonly to allow an intrinsic function to operate on any
5491 integer type. One or more of the argument types or the result type can be
5492 overloaded to accept any integer type. Argument types may also be defined as
5493 exactly matching a previous argument's type or the result type. This allows
5494 an intrinsic function which accepts multiple arguments, but needs all of them
5495 to be of the same type, to only be overloaded with respect to a single
5496 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5497
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5498<p>Overloaded intrinsics will have the names of its overloaded argument types
5499 encoded into its function name, each preceded by a period. Only those types
5500 which are overloaded result in a name suffix. Arguments whose type is matched
5501 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5502 can take an integer of any width and returns an integer of exactly the same
5503 integer width. This leads to a family of functions such as
5504 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5505 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5506 suffix is required. Because the argument's type is matched against the return
5507 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5508
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5509<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5510 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5511
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5512</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5513
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5514<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5515<div class="doc_subsection">
5516 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5517</div>
5518
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5519<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5521<p>Variable argument support is defined in LLVM with
5522 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5523 intrinsic functions. These functions are related to the similarly named
5524 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5526<p>All of these functions operate on arguments that use a target-specific value
5527 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5528 not define what this type is, so all transformations should be prepared to
5529 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5530
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5531<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]5532 instruction and the variable argument handling intrinsic functions are
5533 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5534
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5535<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5536define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5537 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5538 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5539 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5540 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5541
5542 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5543 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5544
5545 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5546 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5547 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5548 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5549 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5550
5551 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5552 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5553 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5554}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5555
5556declare void @llvm.va_start(i8*)
5557declare void @llvm.va_copy(i8*, i8*)
5558declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5559</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5560
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5561</div>
5562
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5564<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5565 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5566</div>
5567
5568
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5569<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5570
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5571<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572<pre>
5573 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5574</pre>
5575
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5576<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5577<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5578 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]5579
5580<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5581<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]5582
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5583<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5584<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]5585 macro available in C. In a target-dependent way, it initializes
5586 the <tt>va_list</tt> element to which the argument points, so that the next
5587 call to <tt>va_arg</tt> will produce the first variable argument passed to
5588 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5589 need to know the last argument of the function as the compiler can figure
5590 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5592</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5593
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5594<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5595<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5596 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5597</div>
5598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5599<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5600
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5601<h5>Syntax:</h5>
5602<pre>
5603 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5604</pre>
5605
5606<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5607<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5608 which has been initialized previously
5609 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5610 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5611
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5612<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5613<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]5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5616<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]5617 macro available in C. In a target-dependent way, it destroys
5618 the <tt>va_list</tt> element to which the argument points. Calls
5619 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5620 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5621 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5623</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5624
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5625<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5626<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5627 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5628</div>
5629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5630<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5631
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5632<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5633<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5634 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5635</pre>
5636
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5637<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5638<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5639 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5640
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5641<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5642<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]5643 The second argument is a pointer to a <tt>va_list</tt> element to copy
5644 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5645
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5646<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5647<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]5648 macro available in C. In a target-dependent way, it copies the
5649 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5650 element. This intrinsic is necessary because
5651 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5652 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5653
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5654</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5655
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5656<!-- ======================================================================= -->
5657<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5658 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5659</div>
5660
5661<div class="doc_text">
5662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5664Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5666roots on the stack</a>, as well as garbage collector implementations that
5667require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5668barriers. Front-ends for type-safe garbage collected languages should generate
5669these intrinsics to make use of the LLVM garbage collectors. For more details,
5670see <a href="GarbageCollection.html">Accurate Garbage Collection with
5671LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5672
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5673<p>The garbage collection intrinsics only operate on objects in the generic
5674 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5675
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676</div>
5677
5678<!-- _______________________________________________________________________ -->
5679<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5680 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5681</div>
5682
5683<div class="doc_text">
5684
5685<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5686<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5687 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688</pre>
5689
5690<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5691<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]5692 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5693
5694<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5695<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5696 root pointer. The second pointer (which must be either a constant or a
5697 global value address) contains the meta-data to be associated with the
5698 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5699
5700<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5701<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]5702 location. At compile-time, the code generator generates information to allow
5703 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5704 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5705 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5706
5707</div>
5708
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5709<!-- _______________________________________________________________________ -->
5710<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5711 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712</div>
5713
5714<div class="doc_text">
5715
5716<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5717<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5718 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5719</pre>
5720
5721<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5722<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723 locations, allowing garbage collector implementations that require read
5724 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5727<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]5728 allocated from the garbage collector. The first object is a pointer to the
5729 start of the referenced object, if needed by the language runtime (otherwise
5730 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5733<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5734 instruction, but may be replaced with substantially more complex code by the
5735 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5736 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_gcwrite">'<tt>llvm.gcwrite</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 void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
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.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5755 locations, allowing garbage collector implementations that require write
5756 barriers (such as generational or reference counting collectors).</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 first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5760 object to store it to, and the third is the address of the field of Obj to
5761 store to. If the runtime does not require a pointer to the object, Obj may
5762 be 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.gcwrite</tt>' intrinsic has the same semantics as a store
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.gcwrite</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_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775 <a name="int_codegen">Code Generator Intrinsics</a>
5776</div>
5777
5778<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5779
5780<p>These intrinsics are provided by LLVM to expose special features that may
5781 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5782
5783</div>
5784
5785<!-- _______________________________________________________________________ -->
5786<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5787 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788</div>
5789
5790<div class="doc_text">
5791
5792<h5>Syntax:</h5>
5793<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5794 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795</pre>
5796
5797<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5799 target-specific value indicating the return address of the current function
5800 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5801
5802<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803<p>The argument to this intrinsic indicates which function to return the address
5804 for. Zero indicates the calling function, one indicates its caller, etc.
5805 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5806
5807<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5809 indicating the return address of the specified call frame, or zero if it
5810 cannot be identified. The value returned by this intrinsic is likely to be
5811 incorrect or 0 for arguments other than zero, so it should only be used for
5812 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814<p>Note that calling this intrinsic does not prevent function inlining or other
5815 aggressive transformations, so the value returned may not be that of the
5816 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5817
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818</div>
5819
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820<!-- _______________________________________________________________________ -->
5821<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5822 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5823</div>
5824
5825<div class="doc_text">
5826
5827<h5>Syntax:</h5>
5828<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5829 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5830</pre>
5831
5832<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5833<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5834 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5835
5836<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5837<p>The argument to this intrinsic indicates which function to return the frame
5838 pointer for. Zero indicates the calling function, one indicates its caller,
5839 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5840
5841<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5842<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5843 indicating the frame address of the specified call frame, or zero if it
5844 cannot be identified. The value returned by this intrinsic is likely to be
5845 incorrect or 0 for arguments other than zero, so it should only be used for
5846 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5847
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>Note that calling this intrinsic does not prevent function inlining or other
5849 aggressive transformations, so the value returned may not be that of the
5850 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5851
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5852</div>
5853
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5854<!-- _______________________________________________________________________ -->
5855<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5856 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5857</div>
5858
5859<div class="doc_text">
5860
5861<h5>Syntax:</h5>
5862<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5863 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5864</pre>
5865
5866<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5867<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5868 of the function stack, for use
5869 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5870 useful for implementing language features like scoped automatic variable
5871 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5872
5873<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5874<p>This intrinsic returns a opaque pointer value that can be passed
5875 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5876 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5877 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5878 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5879 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5880 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5881
5882</div>
5883
5884<!-- _______________________________________________________________________ -->
5885<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5886 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5887</div>
5888
5889<div class="doc_text">
5890
5891<h5>Syntax:</h5>
5892<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5893 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5894</pre>
5895
5896<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5897<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5898 the function stack to the state it was in when the
5899 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5900 executed. This is useful for implementing language features like scoped
5901 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5902
5903<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904<p>See the description
5905 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5906
5907</div>
5908
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5909<!-- _______________________________________________________________________ -->
5910<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5911 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5912</div>
5913
5914<div class="doc_text">
5915
5916<h5>Syntax:</h5>
5917<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5918 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]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5923 insert a prefetch instruction if supported; otherwise, it is a noop.
5924 Prefetches have no effect on the behavior of the program but can change its
5925 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5926
5927<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5928<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5929 specifier determining if the fetch should be for a read (0) or write (1),
5930 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5931 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5932 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5933
5934<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935<p>This intrinsic does not modify the behavior of the program. In particular,
5936 prefetches cannot trap and do not produce a value. On targets that support
5937 this intrinsic, the prefetch can provide hints to the processor cache for
5938 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5939
5940</div>
5941
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5944 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
5950<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5951 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5956 Counter (PC) in a region of code to simulators and other tools. The method
5957 is target specific, but it is expected that the marker will use exported
5958 symbols to transmit the PC of the marker. The marker makes no guarantees
5959 that it will remain with any specific instruction after optimizations. It is
5960 possible that the presence of a marker will inhibit optimizations. The
5961 intended use is to be inserted after optimizations to allow correlations of
5962 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5963
5964<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5966
5967<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5968<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5969 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5970
5971</div>
5972
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5973<!-- _______________________________________________________________________ -->
5974<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5975 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5976</div>
5977
5978<div class="doc_text">
5979
5980<h5>Syntax:</h5>
5981<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5982 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5983</pre>
5984
5985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5986<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5987 counter register (or similar low latency, high accuracy clocks) on those
5988 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5989 should map to RPCC. As the backing counters overflow quickly (on the order
5990 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5991
5992<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5993<p>When directly supported, reading the cycle counter should not modify any
5994 memory. Implementations are allowed to either return a application specific
5995 value or a system wide value. On backends without support, this is lowered
5996 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5997
5998</div>
5999
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6000<!-- ======================================================================= -->
6001<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6002 <a name="int_libc">Standard C Library Intrinsics</a>
6003</div>
6004
6005<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6006
6007<p>LLVM provides intrinsics for a few important standard C library functions.
6008 These intrinsics allow source-language front-ends to pass information about
6009 the alignment of the pointer arguments to the code generator, providing
6010 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6011
6012</div>
6013
6014<!-- _______________________________________________________________________ -->
6015<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6016 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6017</div>
6018
6019<div class="doc_text">
6020
6021<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6022<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]6023 integer bit width and for different address spaces. Not all targets support
6024 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6025
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6026<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6027 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]6028 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6029 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]6030 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6031</pre>
6032
6033<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6034<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6035 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6036
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6038 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6039 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6040
6041<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6042
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043<p>The first argument is a pointer to the destination, the second is a pointer
6044 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6045 number of bytes to copy, the fourth argument is the alignment of the
6046 source and destination locations, and the fifth is a boolean indicating a
6047 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6048
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6049<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]6050 then the caller guarantees that both the source and destination pointers are
6051 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6052
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6053<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6054 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6055 The detailed access behavior is not very cleanly specified and it is unwise
6056 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6057
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6058<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6060<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6061 source location to the destination location, which are not allowed to
6062 overlap. It copies "len" bytes of memory over. If the argument is known to
6063 be aligned to some boundary, this can be specified as the fourth argument,
6064 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6065
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6066</div>
6067
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6068<!-- _______________________________________________________________________ -->
6069<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6070 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6071</div>
6072
6073<div class="doc_text">
6074
6075<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6076<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]6077 width and for different address space. Not all targets support all bit
6078 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6079
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6080<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6081 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]6082 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6083 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]6084 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6085</pre>
6086
6087<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6088<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6089 source location to the destination location. It is similar to the
6090 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6091 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6092
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6094 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6095 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6096
6097<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6098
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099<p>The first argument is a pointer to the destination, the second is a pointer
6100 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6101 number of bytes to copy, the fourth argument is the alignment of the
6102 source and destination locations, and the fifth is a boolean indicating a
6103 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6104
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6105<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]6106 then the caller guarantees that the source and destination pointers are
6107 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6108
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6109<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6110 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6111 The detailed access behavior is not very cleanly specified and it is unwise
6112 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6113
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6114<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6115
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6117 source location to the destination location, which may overlap. It copies
6118 "len" bytes of memory over. If the argument is known to be aligned to some
6119 boundary, this can be specified as the fourth argument, otherwise it should
6120 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6121
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6122</div>
6123
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6124<!-- _______________________________________________________________________ -->
6125<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6126 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6127</div>
6128
6129<div class="doc_text">
6130
6131<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6132<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6133 width and for different address spaces. However, not all targets support all
6134 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6135
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6136<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6137 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6138 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6139 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6140 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6141</pre>
6142
6143<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6144<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6145 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6146
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6147<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6148 intrinsic does not return a value and takes extra alignment/volatile
6149 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6150
6151<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6153 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6154 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6155 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6156
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6157<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]6158 then the caller guarantees that the destination pointer is aligned to that
6159 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6160
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6161<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6162 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6163 The detailed access behavior is not very cleanly specified and it is unwise
6164 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6165
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6166<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6168 at the destination location. If the argument is known to be aligned to some
6169 boundary, this can be specified as the fourth argument, otherwise it should
6170 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6171
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6172</div>
6173
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6174<!-- _______________________________________________________________________ -->
6175<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6176 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6177</div>
6178
6179<div class="doc_text">
6180
6181<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6182<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6183 floating point or vector of floating point type. Not all targets support all
6184 types however.</p>
6185
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6186<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6187 declare float @llvm.sqrt.f32(float %Val)
6188 declare double @llvm.sqrt.f64(double %Val)
6189 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6190 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6191 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6192</pre>
6193
6194<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6195<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6196 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6197 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6198 behavior for negative numbers other than -0.0 (which allows for better
6199 optimization, because there is no need to worry about errno being
6200 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]6201
6202<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The argument and return value are floating point numbers of the same
6204 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6207<p>This function returns the sqrt of the specified operand if it is a
6208 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6209
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6210</div>
6211
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6212<!-- _______________________________________________________________________ -->
6213<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6214 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6215</div>
6216
6217<div class="doc_text">
6218
6219<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6220<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6221 floating point or vector of floating point type. Not all targets support all
6222 types however.</p>
6223
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6224<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6225 declare float @llvm.powi.f32(float %Val, i32 %power)
6226 declare double @llvm.powi.f64(double %Val, i32 %power)
6227 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6228 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6229 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6230</pre>
6231
6232<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6233<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6234 specified (positive or negative) power. The order of evaluation of
6235 multiplications is not defined. When a vector of floating point type is
6236 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6237
6238<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The second argument is an integer power, and the first is a value to raise to
6240 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the first value raised to the second power with an
6244 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6245
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6246</div>
6247
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
6250 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6257 floating point or vector of floating point type. Not all targets support all
6258 types however.</p>
6259
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6260<pre>
6261 declare float @llvm.sin.f32(float %Val)
6262 declare double @llvm.sin.f64(double %Val)
6263 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6264 declare fp128 @llvm.sin.f128(fp128 %Val)
6265 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6269<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6270
6271<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272<p>The argument and return value are floating point numbers of the same
6273 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6274
6275<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276<p>This function returns the sine of the specified operand, returning the same
6277 values as the libm <tt>sin</tt> functions would, and handles error conditions
6278 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6279
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6280</div>
6281
6282<!-- _______________________________________________________________________ -->
6283<div class="doc_subsubsection">
6284 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6285</div>
6286
6287<div class="doc_text">
6288
6289<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6290<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6291 floating point or vector of floating point type. Not all targets support all
6292 types however.</p>
6293
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6294<pre>
6295 declare float @llvm.cos.f32(float %Val)
6296 declare double @llvm.cos.f64(double %Val)
6297 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6298 declare fp128 @llvm.cos.f128(fp128 %Val)
6299 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6300</pre>
6301
6302<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6304
6305<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6306<p>The argument and return value are floating point numbers of the same
6307 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6308
6309<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6310<p>This function returns the cosine of the specified operand, returning the same
6311 values as the libm <tt>cos</tt> functions would, and handles error conditions
6312 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6313
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6314</div>
6315
6316<!-- _______________________________________________________________________ -->
6317<div class="doc_subsubsection">
6318 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6319</div>
6320
6321<div class="doc_text">
6322
6323<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6324<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6325 floating point or vector of floating point type. Not all targets support all
6326 types however.</p>
6327
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6328<pre>
6329 declare float @llvm.pow.f32(float %Val, float %Power)
6330 declare double @llvm.pow.f64(double %Val, double %Power)
6331 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6332 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6333 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6334</pre>
6335
6336<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6337<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6338 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6339
6340<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6341<p>The second argument is a floating point power, and the first is a value to
6342 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6343
6344<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6345<p>This function returns the first value raised to the second power, returning
6346 the same values as the libm <tt>pow</tt> functions would, and handles error
6347 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6348
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6349</div>
6350
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6351<!-- ======================================================================= -->
6352<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6353 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6354</div>
6355
6356<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6357
6358<p>LLVM provides intrinsics for a few important bit manipulation operations.
6359 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6360
6361</div>
6362
6363<!-- _______________________________________________________________________ -->
6364<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6365 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6366</div>
6367
6368<div class="doc_text">
6369
6370<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6371<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6372 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6373
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6374<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6375 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6376 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6377 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6381<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6382 values with an even number of bytes (positive multiple of 16 bits). These
6383 are useful for performing operations on data that is not in the target's
6384 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6385
6386<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6388 and low byte of the input i16 swapped. Similarly,
6389 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6390 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6391 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6392 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6393 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6394 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6395
6396</div>
6397
6398<!-- _______________________________________________________________________ -->
6399<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6400 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6401</div>
6402
6403<div class="doc_text">
6404
6405<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6406<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]6407 width. Not all targets support all bit widths however.</p>
6408
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6409<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6410 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6411 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6412 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6413 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6414 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6415</pre>
6416
6417<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6418<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6419 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6420
6421<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6422<p>The only argument is the value to be counted. The argument may be of any
6423 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6424
6425<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6426<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]6427
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6432 <a name="int_ctlz">'<tt>llvm.ctlz.*</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>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6438<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6439 integer bit width. Not all targets support all bit widths however.</p>
6440
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6441<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6442 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6443 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6444 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6445 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6446 declare i256 @llvm.ctlz.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.ctlz</tt>' family of intrinsic functions counts the number of
6451 leading zeros in a variable.</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.ctlz</tt>' intrinsic counts the leading (most significant)
6459 zeros in a variable. If the src == 0 then the result is the size in bits of
6460 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6461
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6462</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6463
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6464<!-- _______________________________________________________________________ -->
6465<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6466 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6467</div>
6468
6469<div class="doc_text">
6470
6471<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6472<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6473 integer bit width. Not all targets support all bit widths however.</p>
6474
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6475<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6476 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6477 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6478 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6479 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6480 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6481</pre>
6482
6483<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6485 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6486
6487<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6488<p>The only argument is the value to be counted. The argument may be of any
6489 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6490
6491<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6492<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6493 zeros in a variable. If the src == 0 then the result is the size in bits of
6494 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6495
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6496</div>
6497
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6498<!-- ======================================================================= -->
6499<div class="doc_subsection">
6500 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6501</div>
6502
6503<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504
6505<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6506
6507</div>
6508
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6509<!-- _______________________________________________________________________ -->
6510<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6511 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6512</div>
6513
6514<div class="doc_text">
6515
6516<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6517<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]6518 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6519
6520<pre>
6521 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6522 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6523 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6524</pre>
6525
6526<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6528 a signed addition of the two arguments, and indicate whether an overflow
6529 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6530
6531<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532<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]6533 be of integer types of any bit width, but they must have the same bit
6534 width. The second element of the result structure must be of
6535 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6536 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6537
6538<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6539<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540 a signed addition of the two variables. They return a structure &mdash; the
6541 first element of which is the signed summation, and the second element of
6542 which is a bit specifying if the signed summation resulted in an
6543 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6544
6545<h5>Examples:</h5>
6546<pre>
6547 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6548 %sum = extractvalue {i32, i1} %res, 0
6549 %obit = extractvalue {i32, i1} %res, 1
6550 br i1 %obit, label %overflow, label %normal
6551</pre>
6552
6553</div>
6554
6555<!-- _______________________________________________________________________ -->
6556<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6557 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6558</div>
6559
6560<div class="doc_text">
6561
6562<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6563<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]6564 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6565
6566<pre>
6567 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6568 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6569 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6570</pre>
6571
6572<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6574 an unsigned addition of the two arguments, and indicate whether a carry
6575 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6576
6577<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6578<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]6579 be of integer types of any bit width, but they must have the same bit
6580 width. The second element of the result structure must be of
6581 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6582 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6583
6584<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6585<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6586 an unsigned addition of the two arguments. They return a structure &mdash;
6587 the first element of which is the sum, and the second element of which is a
6588 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6589
6590<h5>Examples:</h5>
6591<pre>
6592 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6593 %sum = extractvalue {i32, i1} %res, 0
6594 %obit = extractvalue {i32, i1} %res, 1
6595 br i1 %obit, label %carry, label %normal
6596</pre>
6597
6598</div>
6599
6600<!-- _______________________________________________________________________ -->
6601<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6602 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6603</div>
6604
6605<div class="doc_text">
6606
6607<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6608<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]6609 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6610
6611<pre>
6612 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6613 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6614 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6615</pre>
6616
6617<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6619 a signed subtraction of the two arguments, and indicate whether an overflow
6620 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621
6622<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623<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]6624 be of integer types of any bit width, but they must have the same bit
6625 width. The second element of the result structure must be of
6626 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6627 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6628
6629<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6630<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631 a signed subtraction of the two arguments. They return a structure &mdash;
6632 the first element of which is the subtraction, and the second element of
6633 which is a bit specifying if the signed subtraction resulted in an
6634 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6635
6636<h5>Examples:</h5>
6637<pre>
6638 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6639 %sum = extractvalue {i32, i1} %res, 0
6640 %obit = extractvalue {i32, i1} %res, 1
6641 br i1 %obit, label %overflow, label %normal
6642</pre>
6643
6644</div>
6645
6646<!-- _______________________________________________________________________ -->
6647<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6648 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6649</div>
6650
6651<div class="doc_text">
6652
6653<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6654<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]6655 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6656
6657<pre>
6658 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6659 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6660 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6661</pre>
6662
6663<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6665 an unsigned subtraction of the two arguments, and indicate whether an
6666 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6667
6668<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669<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]6670 be of integer types of any bit width, but they must have the same bit
6671 width. The second element of the result structure must be of
6672 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6673 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6674
6675<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6676<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6677 an unsigned subtraction of the two arguments. They return a structure &mdash;
6678 the first element of which is the subtraction, and the second element of
6679 which is a bit specifying if the unsigned subtraction resulted in an
6680 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6681
6682<h5>Examples:</h5>
6683<pre>
6684 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6685 %sum = extractvalue {i32, i1} %res, 0
6686 %obit = extractvalue {i32, i1} %res, 1
6687 br i1 %obit, label %overflow, label %normal
6688</pre>
6689
6690</div>
6691
6692<!-- _______________________________________________________________________ -->
6693<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6694 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6695</div>
6696
6697<div class="doc_text">
6698
6699<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6700<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]6701 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6702
6703<pre>
6704 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6705 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6706 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6707</pre>
6708
6709<h5>Overview:</h5>
6710
6711<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6712 a signed multiplication of the two arguments, and indicate whether an
6713 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6714
6715<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6716<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]6717 be of integer types of any bit width, but they must have the same bit
6718 width. The second element of the result structure must be of
6719 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6720 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6721
6722<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6723<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724 a signed multiplication of the two arguments. They return a structure &mdash;
6725 the first element of which is the multiplication, and the second element of
6726 which is a bit specifying if the signed multiplication resulted in an
6727 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6728
6729<h5>Examples:</h5>
6730<pre>
6731 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6732 %sum = extractvalue {i32, i1} %res, 0
6733 %obit = extractvalue {i32, i1} %res, 1
6734 br i1 %obit, label %overflow, label %normal
6735</pre>
6736
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6737</div>
6738
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6739<!-- _______________________________________________________________________ -->
6740<div class="doc_subsubsection">
6741 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6742</div>
6743
6744<div class="doc_text">
6745
6746<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6747<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]6748 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6749
6750<pre>
6751 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6752 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6753 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6754</pre>
6755
6756<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6757<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6758 a unsigned multiplication of the two arguments, and indicate whether an
6759 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6760
6761<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6762<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]6763 be of integer types of any bit width, but they must have the same bit
6764 width. The second element of the result structure must be of
6765 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6766 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6767
6768<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6769<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6770 an unsigned multiplication of the two arguments. They return a structure
6771 &mdash; the first element of which is the multiplication, and the second
6772 element of which is a bit specifying if the unsigned multiplication resulted
6773 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6774
6775<h5>Examples:</h5>
6776<pre>
6777 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6778 %sum = extractvalue {i32, i1} %res, 0
6779 %obit = extractvalue {i32, i1} %res, 1
6780 br i1 %obit, label %overflow, label %normal
6781</pre>
6782
6783</div>
6784
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6785<!-- ======================================================================= -->
6786<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6787 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6788</div>
6789
6790<div class="doc_text">
6791
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6792<p>Half precision floating point is a storage-only format. This means that it is
6793 a dense encoding (in memory) but does not support computation in the
6794 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6795
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6796<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6797 value as an i16, then convert it to float with <a
6798 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6799 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6800 double etc). To store the value back to memory, it is first converted to
6801 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6802 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6803 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6804</div>
6805
6806<!-- _______________________________________________________________________ -->
6807<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6808 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6809</div>
6810
6811<div class="doc_text">
6812
6813<h5>Syntax:</h5>
6814<pre>
6815 declare i16 @llvm.convert.to.fp16(f32 %a)
6816</pre>
6817
6818<h5>Overview:</h5>
6819<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6820 a conversion from single precision floating point format to half precision
6821 floating point format.</p>
6822
6823<h5>Arguments:</h5>
6824<p>The intrinsic function contains single argument - the value to be
6825 converted.</p>
6826
6827<h5>Semantics:</h5>
6828<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6829 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6830 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6831 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6832
6833<h5>Examples:</h5>
6834<pre>
6835 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6836 store i16 %res, i16* @x, align 2
6837</pre>
6838
6839</div>
6840
6841<!-- _______________________________________________________________________ -->
6842<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6843 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6844</div>
6845
6846<div class="doc_text">
6847
6848<h5>Syntax:</h5>
6849<pre>
6850 declare f32 @llvm.convert.from.fp16(i16 %a)
6851</pre>
6852
6853<h5>Overview:</h5>
6854<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6855 a conversion from half precision floating point format to single precision
6856 floating point format.</p>
6857
6858<h5>Arguments:</h5>
6859<p>The intrinsic function contains single argument - the value to be
6860 converted.</p>
6861
6862<h5>Semantics:</h5>
6863<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6864 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6865 precision floating point format. The input half-float value is represented by
6866 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6867
6868<h5>Examples:</h5>
6869<pre>
6870 %a = load i16* @x, align 2
6871 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6872</pre>
6873
6874</div>
6875
6876<!-- ======================================================================= -->
6877<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6878 <a name="int_debugger">Debugger Intrinsics</a>
6879</div>
6880
6881<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6882
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6884 prefix), are described in
6885 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6886 Level Debugging</a> document.</p>
6887
6888</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6889
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6890<!-- ======================================================================= -->
6891<div class="doc_subsection">
6892 <a name="int_eh">Exception Handling Intrinsics</a>
6893</div>
6894
6895<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6896
6897<p>The LLVM exception handling intrinsics (which all start with
6898 <tt>llvm.eh.</tt> prefix), are described in
6899 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6900 Handling</a> document.</p>
6901
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6902</div>
6903
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6904<!-- ======================================================================= -->
6905<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6906 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6907</div>
6908
6909<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910
6911<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6912 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6913 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6914 function pointer lacking the nest parameter - the caller does not need to
6915 provide a value for it. Instead, the value to use is stored in advance in a
6916 "trampoline", a block of memory usually allocated on the stack, which also
6917 contains code to splice the nest value into the argument list. This is used
6918 to implement the GCC nested function address extension.</p>
6919
6920<p>For example, if the function is
6921 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6922 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6923 follows:</p>
6924
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6925<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6926 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6927 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6928 %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]6929 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6930</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6931
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6932<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6933 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6935</div>
6936
6937<!-- _______________________________________________________________________ -->
6938<div class="doc_subsubsection">
6939 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6940</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6942<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6944<h5>Syntax:</h5>
6945<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946 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]6947</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6948
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6949<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6951 function pointer suitable for executing it.</p>
6952
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6953<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6955 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6956 sufficiently aligned block of memory; this memory is written to by the
6957 intrinsic. Note that the size and the alignment are target-specific - LLVM
6958 currently provides no portable way of determining them, so a front-end that
6959 generates this intrinsic needs to have some target-specific knowledge.
6960 The <tt>func</tt> argument must hold a function bitcast to
6961 an <tt>i8*</tt>.</p>
6962
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6963<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6964<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6965 dependent code, turning it into a function. A pointer to this function is
6966 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6967 function pointer type</a> before being called. The new function's signature
6968 is the same as that of <tt>func</tt> with any arguments marked with
6969 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6970 is allowed, and it must be of pointer type. Calling the new function is
6971 equivalent to calling <tt>func</tt> with the same argument list, but
6972 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6973 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6974 by <tt>tramp</tt> is modified, then the effect of any later call to the
6975 returned function pointer is undefined.</p>
6976
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6977</div>
6978
6979<!-- ======================================================================= -->
6980<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6981 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6982</div>
6983
6984<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6985
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6987 hardware constructs for atomic operations and memory synchronization. This
6988 provides an interface to the hardware, not an interface to the programmer. It
6989 is aimed at a low enough level to allow any programming models or APIs
6990 (Application Programming Interfaces) which need atomic behaviors to map
6991 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6992 hardware provides a "universal IR" for source languages, it also provides a
6993 starting point for developing a "universal" atomic operation and
6994 synchronization IR.</p>
6995
6996<p>These do <em>not</em> form an API such as high-level threading libraries,
6997 software transaction memory systems, atomic primitives, and intrinsic
6998 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6999 application libraries. The hardware interface provided by LLVM should allow
7000 a clean implementation of all of these APIs and parallel programming models.
7001 No one model or paradigm should be selected above others unless the hardware
7002 itself ubiquitously does so.</p>
7003
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7004</div>
7005
7006<!-- _______________________________________________________________________ -->
7007<div class="doc_subsubsection">
7008 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7009</div>
7010<div class="doc_text">
7011<h5>Syntax:</h5>
7012<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7013 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]7014</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7015
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7016<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7017<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7018 specific pairs of memory access types.</p>
7019
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7020<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7021<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7022 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7023 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7026<ul>
7027 <li><tt>ll</tt>: load-load barrier</li>
7028 <li><tt>ls</tt>: load-store barrier</li>
7029 <li><tt>sl</tt>: store-load barrier</li>
7030 <li><tt>ss</tt>: store-store barrier</li>
7031 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7032</ul>
7033
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7034<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7035<p>This intrinsic causes the system to enforce some ordering constraints upon
7036 the loads and stores of the program. This barrier does not
7037 indicate <em>when</em> any events will occur, it only enforces
7038 an <em>order</em> in which they occur. For any of the specified pairs of load
7039 and store operations (f.ex. load-load, or store-load), all of the first
7040 operations preceding the barrier will complete before any of the second
7041 operations succeeding the barrier begin. Specifically the semantics for each
7042 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7043
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7044<ul>
7045 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7046 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7047 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7048 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7049 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7051 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052 load after the barrier begins.</li>
7053</ul>
7054
7055<p>These semantics are applied with a logical "and" behavior when more than one
7056 is enabled in a single memory barrier intrinsic.</p>
7057
7058<p>Backends may implement stronger barriers than those requested when they do
7059 not support as fine grained a barrier as requested. Some architectures do
7060 not need all types of barriers and on such architectures, these become
7061 noops.</p>
7062
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7063<h5>Example:</h5>
7064<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7065%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7066%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7067 store i32 4, %ptr
7068
7069%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7070 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7071 <i>; guarantee the above finishes</i>
7072 store i32 8, %ptr <i>; before this begins</i>
7073</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7075</div>
7076
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7077<!-- _______________________________________________________________________ -->
7078<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7079 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7080</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7082<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7083
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7084<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7085<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7086 any integer bit width and for different address spaces. Not all targets
7087 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7088
7089<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7090 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7091 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7092 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7093 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]7094</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7095
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7096<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097<p>This loads a value in memory and compares it to a given value. If they are
7098 equal, it stores a new value into the memory.</p>
7099
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7100<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7101<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7102 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7103 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7104 this integer type. While any bit width integer may be used, targets may only
7105 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7106
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7107<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108<p>This entire intrinsic must be executed atomically. It first loads the value
7109 in memory pointed to by <tt>ptr</tt> and compares it with the
7110 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7111 memory. The loaded value is yielded in all cases. This provides the
7112 equivalent of an atomic compare-and-swap operation within the SSA
7113 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7114
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7115<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7116<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7117%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7118%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7119 store i32 4, %ptr
7120
7121%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7122%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7123 <i>; yields {i32}:result1 = 4</i>
7124%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7125%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7126
7127%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7128%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129 <i>; yields {i32}:result2 = 8</i>
7130%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7131
7132%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7133</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7135</div>
7136
7137<!-- _______________________________________________________________________ -->
7138<div class="doc_subsubsection">
7139 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7140</div>
7141<div class="doc_text">
7142<h5>Syntax:</h5>
7143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7144<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7145 integer bit width. Not all targets support all bit widths however.</p>
7146
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7147<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7148 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7149 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7150 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7151 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]7152</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7153
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7154<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7155<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7156 the value from memory. It then stores the value in <tt>val</tt> in the memory
7157 at <tt>ptr</tt>.</p>
7158
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7161 the <tt>val</tt> argument and the result must be integers of the same bit
7162 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7163 integer type. The targets may only lower integer representations they
7164 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7168 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7169 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7171<h5>Examples:</h5>
7172<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7173%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7174%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175 store i32 4, %ptr
7176
7177%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7178%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7179 <i>; yields {i32}:result1 = 4</i>
7180%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7181%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7182
7183%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7184%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7185 <i>; yields {i32}:result2 = 8</i>
7186
7187%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7188%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7189</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191</div>
7192
7193<!-- _______________________________________________________________________ -->
7194<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7195 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7196
7197</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7198
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7199<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7200
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7202<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7203 any integer bit width. Not all targets support all bit widths however.</p>
7204
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7205<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7206 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7207 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7208 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7209 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]7210</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212<h5>Overview:</h5>
7213<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7214 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7215
7216<h5>Arguments:</h5>
7217<p>The intrinsic takes two arguments, the first a pointer to an integer value
7218 and the second an integer value. The result is also an integer value. These
7219 integer types can have any bit width, but they must all have the same bit
7220 width. The targets may only lower integer representations they support.</p>
7221
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7222<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7223<p>This intrinsic does a series of operations atomically. It first loads the
7224 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7225 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]7226
7227<h5>Examples:</h5>
7228<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7229%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7230%ptr = bitcast i8* %mallocP to i32*
7231 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7232%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7233 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7234%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7235 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7236%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7237 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7238%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7239</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7241</div>
7242
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7243<!-- _______________________________________________________________________ -->
7244<div class="doc_subsubsection">
7245 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7246
7247</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7249<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7250
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7251<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7252<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7253 any integer bit width and for different address spaces. Not all targets
7254 support all bit widths however.</p>
7255
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7256<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7257 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7258 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7259 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7260 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]7261</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7262
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7263<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7264<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7266
7267<h5>Arguments:</h5>
7268<p>The intrinsic takes two arguments, the first a pointer to an integer value
7269 and the second an integer value. The result is also an integer value. These
7270 integer types can have any bit width, but they must all have the same bit
7271 width. The targets may only lower integer representations they support.</p>
7272
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7273<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7274<p>This intrinsic does a series of operations atomically. It first loads the
7275 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7276 result to <tt>ptr</tt>. It yields the original value stored
7277 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7278
7279<h5>Examples:</h5>
7280<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7281%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7282%ptr = bitcast i8* %mallocP to i32*
7283 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7284%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7285 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7286%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7287 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7288%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7289 <i>; yields {i32}:result3 = 2</i>
7290%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7291</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7292
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7293</div>
7294
7295<!-- _______________________________________________________________________ -->
7296<div class="doc_subsubsection">
7297 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7298 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7299 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7300 <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]7301</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7302
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7303<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7304
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7305<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7306<p>These are overloaded intrinsics. You can
7307 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7308 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7309 bit width and for different address spaces. Not all targets support all bit
7310 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7312<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7313 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7314 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7315 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7316 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]7317</pre>
7318
7319<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7320 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7321 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7322 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7323 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]7324</pre>
7325
7326<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7327 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7328 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7329 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7330 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]7331</pre>
7332
7333<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7334 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7335 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7336 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7337 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]7338</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7339
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7340<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7341<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7342 the value stored in memory at <tt>ptr</tt>. It yields the original value
7343 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7344
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7345<h5>Arguments:</h5>
7346<p>These intrinsics take two arguments, the first a pointer to an integer value
7347 and the second an integer value. The result is also an integer value. These
7348 integer types can have any bit width, but they must all have the same bit
7349 width. The targets may only lower integer representations they support.</p>
7350
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7351<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352<p>These intrinsics does a series of operations atomically. They first load the
7353 value stored at <tt>ptr</tt>. They then do the bitwise
7354 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7355 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7356
7357<h5>Examples:</h5>
7358<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7359%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7360%ptr = bitcast i8* %mallocP to i32*
7361 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7362%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7363 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7364%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7365 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7366%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7367 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7368%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7369 <i>; yields {i32}:result3 = FF</i>
7370%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7371</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7372
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7373</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7374
7375<!-- _______________________________________________________________________ -->
7376<div class="doc_subsubsection">
7377 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7378 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7379 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7380 <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]7381</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7382
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7383<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7384
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7385<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7386<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7387 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7388 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7389 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7390
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7392 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7393 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7394 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7395 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]7396</pre>
7397
7398<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7399 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7400 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7401 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7402 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]7403</pre>
7404
7405<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7406 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7407 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7408 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7409 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]7410</pre>
7411
7412<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7413 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7414 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7415 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7416 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]7417</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7420<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7422 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7423
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7424<h5>Arguments:</h5>
7425<p>These intrinsics take two arguments, the first a pointer to an integer value
7426 and the second an integer value. The result is also an integer value. These
7427 integer types can have any bit width, but they must all have the same bit
7428 width. The targets may only lower integer representations they support.</p>
7429
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7430<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7431<p>These intrinsics does a series of operations atomically. They first load the
7432 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7433 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7434 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7435
7436<h5>Examples:</h5>
7437<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7438%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7439%ptr = bitcast i8* %mallocP to i32*
7440 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7441%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7442 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7443%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7444 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7445%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7446 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7447%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7448 <i>; yields {i32}:result3 = 8</i>
7449%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
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</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7453
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7454
7455<!-- ======================================================================= -->
7456<div class="doc_subsection">
7457 <a name="int_memorymarkers">Memory Use Markers</a>
7458</div>
7459
7460<div class="doc_text">
7461
7462<p>This class of intrinsics exists to information about the lifetime of memory
7463 objects and ranges where variables are immutable.</p>
7464
7465</div>
7466
7467<!-- _______________________________________________________________________ -->
7468<div class="doc_subsubsection">
7469 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7470</div>
7471
7472<div class="doc_text">
7473
7474<h5>Syntax:</h5>
7475<pre>
7476 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7477</pre>
7478
7479<h5>Overview:</h5>
7480<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7481 object's lifetime.</p>
7482
7483<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7484<p>The first argument is a constant integer representing the size of the
7485 object, or -1 if it is variable sized. The second argument is a pointer to
7486 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7487
7488<h5>Semantics:</h5>
7489<p>This intrinsic indicates that before this point in the code, the value of the
7490 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]7491 never be used and has an undefined value. A load from the pointer that
7492 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7493 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7494
7495</div>
7496
7497<!-- _______________________________________________________________________ -->
7498<div class="doc_subsubsection">
7499 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7500</div>
7501
7502<div class="doc_text">
7503
7504<h5>Syntax:</h5>
7505<pre>
7506 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7507</pre>
7508
7509<h5>Overview:</h5>
7510<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7511 object's lifetime.</p>
7512
7513<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7514<p>The first argument is a constant integer representing the size of the
7515 object, or -1 if it is variable sized. The second argument is a pointer to
7516 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7517
7518<h5>Semantics:</h5>
7519<p>This intrinsic indicates that after this point in the code, the value of the
7520 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7521 never be used and has an undefined value. Any stores into the memory object
7522 following this intrinsic may be removed as dead.
7523
7524</div>
7525
7526<!-- _______________________________________________________________________ -->
7527<div class="doc_subsubsection">
7528 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7529</div>
7530
7531<div class="doc_text">
7532
7533<h5>Syntax:</h5>
7534<pre>
7535 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7536</pre>
7537
7538<h5>Overview:</h5>
7539<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7540 a memory object will not change.</p>
7541
7542<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7543<p>The first argument is a constant integer representing the size of the
7544 object, or -1 if it is variable sized. The second argument is a pointer to
7545 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7546
7547<h5>Semantics:</h5>
7548<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7549 the return value, the referenced memory location is constant and
7550 unchanging.</p>
7551
7552</div>
7553
7554<!-- _______________________________________________________________________ -->
7555<div class="doc_subsubsection">
7556 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7557</div>
7558
7559<div class="doc_text">
7560
7561<h5>Syntax:</h5>
7562<pre>
7563 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7564</pre>
7565
7566<h5>Overview:</h5>
7567<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7568 a memory object are mutable.</p>
7569
7570<h5>Arguments:</h5>
7571<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7572 The second argument is a constant integer representing the size of the
7573 object, or -1 if it is variable sized and the third argument is a pointer
7574 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7575
7576<h5>Semantics:</h5>
7577<p>This intrinsic indicates that the memory is mutable again.</p>
7578
7579</div>
7580
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7581<!-- ======================================================================= -->
7582<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7583 <a name="int_general">General Intrinsics</a>
7584</div>
7585
7586<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7587
7588<p>This class of intrinsics is designed to be generic and has no specific
7589 purpose.</p>
7590
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7591</div>
7592
7593<!-- _______________________________________________________________________ -->
7594<div class="doc_subsubsection">
7595 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7596</div>
7597
7598<div class="doc_text">
7599
7600<h5>Syntax:</h5>
7601<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7602 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]7603</pre>
7604
7605<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7606<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7607
7608<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7609<p>The first argument is a pointer to a value, the second is a pointer to a
7610 global string, the third is a pointer to a global string which is the source
7611 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7612
7613<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7614<p>This intrinsic allows annotation of local variables with arbitrary strings.
7615 This can be useful for special purpose optimizations that want to look for
7616 these annotations. These have no other defined use, they are ignored by code
7617 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7618
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7619</div>
7620
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7621<!-- _______________________________________________________________________ -->
7622<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7623 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7624</div>
7625
7626<div class="doc_text">
7627
7628<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7629<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7630 any integer bit width.</p>
7631
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7632<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7633 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7634 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7635 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7636 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7637 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]7638</pre>
7639
7640<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7641<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7642
7643<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7644<p>The first argument is an integer value (result of some expression), the
7645 second is a pointer to a global string, the third is a pointer to a global
7646 string which is the source file name, and the last argument is the line
7647 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7650<p>This intrinsic allows annotations to be put on arbitrary expressions with
7651 arbitrary strings. This can be useful for special purpose optimizations that
7652 want to look for these annotations. These have no other defined use, they
7653 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7654
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7655</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7656
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7657<!-- _______________________________________________________________________ -->
7658<div class="doc_subsubsection">
7659 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7660</div>
7661
7662<div class="doc_text">
7663
7664<h5>Syntax:</h5>
7665<pre>
7666 declare void @llvm.trap()
7667</pre>
7668
7669<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7670<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7671
7672<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7673<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7674
7675<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7676<p>This intrinsics is lowered to the target dependent trap instruction. If the
7677 target does not have a trap instruction, this intrinsic will be lowered to
7678 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7679
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7680</div>
7681
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7682<!-- _______________________________________________________________________ -->
7683<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7684 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7685</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7686
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7687<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7689<h5>Syntax:</h5>
7690<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7691 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7692</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7693
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7694<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7695<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7696 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7697 ensure that it is placed on the stack before local variables.</p>
7698
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7699<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7700<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7701 arguments. The first argument is the value loaded from the stack
7702 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7703 that has enough space to hold the value of the guard.</p>
7704
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7705<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7707 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7708 stack. This is to ensure that if a local variable on the stack is
7709 overwritten, it will destroy the value of the guard. When the function exits,
7710 the guard on the stack is checked against the original guard. If they're
7711 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7712 function.</p>
7713
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7714</div>
7715
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7716<!-- _______________________________________________________________________ -->
7717<div class="doc_subsubsection">
7718 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7719</div>
7720
7721<div class="doc_text">
7722
7723<h5>Syntax:</h5>
7724<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7725 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7726 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7727</pre>
7728
7729<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7730<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7731 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7732 operation like memcpy will either overflow a buffer that corresponds to
7733 an object, or b) to determine that a runtime check for overflow isn't
7734 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7735 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7736
7737<h5>Arguments:</h5>
7738<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7739 argument is a pointer to or into the <tt>object</tt>. The second argument
7740 is a boolean 0 or 1. This argument determines whether you want the
7741 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7742 1, variables are not allowed.</p>
7743
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7744<h5>Semantics:</h5>
7745<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7746 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7747 (depending on the <tt>type</tt> argument if the size cannot be determined
7748 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7749
7750</div>
7751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7752<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7753<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7754<address>
7755 <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]7759
7760 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7761 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7762 Last modified: $Date$
7763</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7764
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7765</body>
7766</html>