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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 5cc88a205dc8c3009cd7f2b8165c2757082871a5 / . / 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>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]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
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1134 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1135 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1136 meaning the function can be patched and/or hooked even while it is
1137 loaded into memory. On x86, the function prologue will be preceded
1138 by six bytes of padding and will begin with a two-byte instruction.
1139 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1140 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1141
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1142 <dt><tt><b>inlinehint</b></tt></dt>
1143 <dd>This attribute indicates that the source code contained a hint that inlining
1144 this function is desirable (such as the "inline" keyword in C/C++). It
1145 is just a hint; it imposes no requirements on the inliner.</dd>
1146
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1147 <dt><tt><b>naked</b></tt></dt>
1148 <dd>This attribute disables prologue / epilogue emission for the function.
1149 This can have very system-specific consequences.</dd>
1150
1151 <dt><tt><b>noimplicitfloat</b></tt></dt>
1152 <dd>This attributes disables implicit floating point instructions.</dd>
1153
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the inliner should never inline this
1156 function in any situation. This attribute may not be used together with
1157 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1158
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1159 <dt><tt><b>noredzone</b></tt></dt>
1160 <dd>This attribute indicates that the code generator should not use a red
1161 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1162
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1163 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1164 <dd>This function attribute indicates that the function never returns
1165 normally. This produces undefined behavior at runtime if the function
1166 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1167
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This function attribute indicates that the function never returns with an
1170 unwind or exceptional control flow. If the function does unwind, its
1171 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1172
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>optsize</b></tt></dt>
1174 <dd>This attribute suggests that optimization passes and code generator passes
1175 make choices that keep the code size of this function low, and otherwise
1176 do optimizations specifically to reduce code size.</dd>
1177
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1178 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1179 <dd>This attribute indicates that the function computes its result (or decides
1180 to unwind an exception) based strictly on its arguments, without
1181 dereferencing any pointer arguments or otherwise accessing any mutable
1182 state (e.g. memory, control registers, etc) visible to caller functions.
1183 It does not write through any pointer arguments
1184 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1185 changes any state visible to callers. This means that it cannot unwind
1186 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1187 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1188
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This attribute indicates that the function does not write through any
1191 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1192 arguments) or otherwise modify any state (e.g. memory, control registers,
1193 etc) visible to caller functions. It may dereference pointer arguments
1194 and read state that may be set in the caller. A readonly function always
1195 returns the same value (or unwinds an exception identically) when called
1196 with the same set of arguments and global state. It cannot unwind an
1197 exception by calling the <tt>C++</tt> exception throwing methods, but may
1198 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attribute indicates that the function should emit a stack smashing
1202 protector. It is in the form of a "canary"&mdash;a random value placed on
1203 the stack before the local variables that's checked upon return from the
1204 function to see if it has been overwritten. A heuristic is used to
1205 determine if a function needs stack protectors or not.<br>
1206<br>
1207 If a function that has an <tt>ssp</tt> attribute is inlined into a
1208 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1209 function will have an <tt>ssp</tt> attribute.</dd>
1210
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1211 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212 <dd>This attribute indicates that the function should <em>always</em> emit a
1213 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1214 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1215<br>
1216 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1217 function that doesn't have an <tt>sspreq</tt> attribute or which has
1218 an <tt>ssp</tt> attribute, then the resulting function will have
1219 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1220</dl>
1221
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1222</div>
1223
1224<!-- ======================================================================= -->
1225<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1226 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1227</div>
1228
1229<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230
1231<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1232 the GCC "file scope inline asm" blocks. These blocks are internally
1233 concatenated by LLVM and treated as a single unit, but may be separated in
1234 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1235
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1236<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1237module asm "inline asm code goes here"
1238module asm "more can go here"
1239</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1240
1241<p>The strings can contain any character by escaping non-printable characters.
1242 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]1243 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1244
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1245<p>The inline asm code is simply printed to the machine code .s file when
1246 assembly code is generated.</p>
1247
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1248</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1249
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1250<!-- ======================================================================= -->
1251<div class="doc_subsection">
1252 <a name="datalayout">Data Layout</a>
1253</div>
1254
1255<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1256
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1257<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1258 data is to be laid out in memory. The syntax for the data layout is
1259 simply:</p>
1260
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1261<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262target datalayout = "<i>layout specification</i>"
1263</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1264
1265<p>The <i>layout specification</i> consists of a list of specifications
1266 separated by the minus sign character ('-'). Each specification starts with
1267 a letter and may include other information after the letter to define some
1268 aspect of the data layout. The specifications accepted are as follows:</p>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270<dl>
1271 <dt><tt>E</tt></dt>
1272 <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]1273 bits with the most significance have the lowest address location.</dd>
1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1276 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1277 the bits with the least significance have the lowest address
1278 location.</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>preferred</i> alignments. All sizes are in bits. Specifying
1283 the <i>pref</i> alignment is optional. If omitted, the
1284 preceding <tt>:</tt> should be omitted too.</dd>
1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1287 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1289
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1290 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1291 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292 <i>size</i>.</dd>
1293
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1294 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1295 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1296 <i>size</i>. Only values of <i>size</i> that are supported by the target
1297 will work. 32 (float) and 64 (double) are supported on all targets;
1298 80 or 128 (different flavors of long double) are also supported on some
1299 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1301 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1302 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303 <i>size</i>.</dd>
1304
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1305 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1306 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1308
1309 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1310 <dd>This specifies a set of native integer widths for the target CPU
1311 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1312 "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]1313 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1314 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1315</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1318 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 specifications in the <tt>datalayout</tt> keyword. The default specifications
1320 are given in this list:</p>
1321
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322<ul>
1323 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1324 <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]1325 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1326 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1327 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1328 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1329 <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]1330 alignment of 64-bits</li>
1331 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1332 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1333 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1334 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1335 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1336 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338
1339<p>When LLVM is determining the alignment for a given type, it uses the
1340 following rules:</p>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342<ol>
1343 <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]1344 specification is used.</li>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346 <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]1347 smallest integer type that is larger than the bitwidth of the sought type
1348 is used. If none of the specifications are larger than the bitwidth then
1349 the the largest integer type is used. For example, given the default
1350 specifications above, the i7 type will use the alignment of i8 (next
1351 largest) while both i65 and i256 will use the alignment of i64 (largest
1352 specified).</li>
1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354 <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]1355 largest vector type that is smaller than the sought vector type will be
1356 used as a fall back. This happens because &lt;128 x double&gt; can be
1357 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1359
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1361
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1365</div>
1366
1367<div class="doc_text">
1368
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1369<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1370with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1371is undefined. Pointer values are associated with address ranges
1372according to the following rules:</p>
1373
1374<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1375 <li>A pointer value is associated with the addresses associated with
1376 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1377 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1378 range of the variable's storage.</li>
1379 <li>The result value of an allocation instruction is associated with
1380 the address range of the allocated storage.</li>
1381 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1382 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1383 <li>An integer constant other than zero or a pointer value returned
1384 from a function not defined within LLVM may be associated with address
1385 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1386 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1387 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1388</ul>
1389
1390<p>A pointer value is <i>based</i> on another pointer value according
1391 to the following rules:</p>
1392
1393<ul>
1394 <li>A pointer value formed from a
1395 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1396 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1397 <li>The result value of a
1398 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1399 of the <tt>bitcast</tt>.</li>
1400 <li>A pointer value formed by an
1401 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1402 pointer values that contribute (directly or indirectly) to the
1403 computation of the pointer's value.</li>
1404 <li>The "<i>based</i> on" relationship is transitive.</li>
1405</ul>
1406
1407<p>Note that this definition of <i>"based"</i> is intentionally
1408 similar to the definition of <i>"based"</i> in C99, though it is
1409 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1410
1411<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1412<tt><a href="#i_load">load</a></tt> merely indicates the size and
1413alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1414interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1415<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1416and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>Consequently, type-based alias analysis, aka TBAA, aka
1419<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1420LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1421additional information which specialized optimization passes may use
1422to implement type-based alias analysis.</p>
1423
1424</div>
1425
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1426<!-- ======================================================================= -->
1427<div class="doc_subsection">
1428 <a name="volatile">Volatile Memory Accesses</a>
1429</div>
1430
1431<div class="doc_text">
1432
1433<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1434href="#i_store"><tt>store</tt></a>s, and <a
1435href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1436The optimizers must not change the number of volatile operations or change their
1437order of execution relative to other volatile operations. The optimizers
1438<i>may</i> change the order of volatile operations relative to non-volatile
1439operations. This is not Java's "volatile" and has no cross-thread
1440synchronization behavior.</p>
1441
1442</div>
1443
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1444<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1446<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1450<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1451 intermediate representation. Being typed enables a number of optimizations
1452 to be performed on the intermediate representation directly, without having
1453 to do extra analyses on the side before the transformation. A strong type
1454 system makes it easier to read the generated code and enables novel analyses
1455 and transformations that are not feasible to perform on normal three address
1456 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1457
1458</div>
1459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1465
1466<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1467
1468<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1470 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1472 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1473 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
1475 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476 <td><a href="#t_floating">floating point</a></td>
1477 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478 </tr>
1479 <tr>
1480 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481 <td><a href="#t_integer">integer</a>,
1482 <a href="#t_floating">floating point</a>,
1483 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1484 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1485 <a href="#t_struct">structure</a>,
1486 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1487 <a href="#t_label">label</a>,
1488 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1489 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1491 <tr>
1492 <td><a href="#t_primitive">primitive</a></td>
1493 <td><a href="#t_label">label</a>,
1494 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1496 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1497 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1498 </tr>
1499 <tr>
1500 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1501 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502 <a href="#t_function">function</a>,
1503 <a href="#t_pointer">pointer</a>,
1504 <a href="#t_struct">structure</a>,
1505 <a href="#t_pstruct">packed structure</a>,
1506 <a href="#t_vector">vector</a>,
1507 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1508 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1510 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1513<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1514 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1515 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1517</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1519<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1520<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1521
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1522<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1523
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1524<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1525 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1527</div>
1528
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1530<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1531
1532<div class="doc_text">
1533
1534<h5>Overview:</h5>
1535<p>The integer type is a very simple type that simply specifies an arbitrary
1536 bit width for the integer type desired. Any bit width from 1 bit to
1537 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1538
1539<h5>Syntax:</h5>
1540<pre>
1541 iN
1542</pre>
1543
1544<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1545 value.</p>
1546
1547<h5>Examples:</h5>
1548<table class="layout">
1549 <tr class="layout">
1550 <td class="left"><tt>i1</tt></td>
1551 <td class="left">a single-bit integer.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>i32</tt></td>
1555 <td class="left">a 32-bit integer.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>i1942652</tt></td>
1559 <td class="left">a really big integer of over 1 million bits.</td>
1560 </tr>
1561</table>
1562
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1563</div>
1564
1565<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1566<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1567
1568<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1569
1570<table>
1571 <tbody>
1572 <tr><th>Type</th><th>Description</th></tr>
1573 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1574 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1575 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1576 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1577 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1578 </tbody>
1579</table>
1580
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1581</div>
1582
1583<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1585
1586<div class="doc_text">
1587
1588<h5>Overview:</h5>
1589<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1590
1591<h5>Syntax:</h5>
1592<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1593 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1594</pre>
1595
1596</div>
1597
1598<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1599<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1600
1601<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1602
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1603<h5>Overview:</h5>
1604<p>The void type does not represent any value and has no size.</p>
1605
1606<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607<pre>
1608 void
1609</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1611</div>
1612
1613<!-- _______________________________________________________________________ -->
1614<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1615
1616<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1617
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1618<h5>Overview:</h5>
1619<p>The label type represents code labels.</p>
1620
1621<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<pre>
1623 label
1624</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1625
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626</div>
1627
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1628<!-- _______________________________________________________________________ -->
1629<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1630
1631<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1632
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1633<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1634<p>The metadata type represents embedded metadata. No derived types may be
1635 created from metadata except for <a href="#t_function">function</a>
1636 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1637
1638<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1639<pre>
1640 metadata
1641</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1642
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1643</div>
1644
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1645
1646<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1647<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The real power in LLVM comes from the derived types in the system. This is
1652 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1653 useful types. Each of these types contain one or more element types which
1654 may be a primitive type, or another derived type. For example, it is
1655 possible to have a two dimensional array, using an array as the element type
1656 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1657
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1658
1659</div>
1660
1661<!-- _______________________________________________________________________ -->
1662<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1663
1664<div class="doc_text">
1665
1666<p>Aggregate Types are a subset of derived types that can contain multiple
1667 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1668 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1669 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1670
1671</div>
1672
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1673<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1674<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680 sequentially in memory. The array type requires a size (number of elements)
1681 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1682
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1684<pre>
1685 [&lt;# elements&gt; x &lt;elementtype&gt;]
1686</pre>
1687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1688<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1689 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1690
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1691<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1692<table class="layout">
1693 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1694 <td class="left"><tt>[40 x i32]</tt></td>
1695 <td class="left">Array of 40 32-bit integer values.</td>
1696 </tr>
1697 <tr class="layout">
1698 <td class="left"><tt>[41 x i32]</tt></td>
1699 <td class="left">Array of 41 32-bit integer values.</td>
1700 </tr>
1701 <tr class="layout">
1702 <td class="left"><tt>[4 x i8]</tt></td>
1703 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1704 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1706<p>Here are some examples of multidimensional arrays:</p>
1707<table class="layout">
1708 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1709 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1710 <td class="left">3x4 array of 32-bit integer values.</td>
1711 </tr>
1712 <tr class="layout">
1713 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1714 <td class="left">12x10 array of single precision floating point values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1718 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1719 </tr>
1720</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1721
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1722<p>There is no restriction on indexing beyond the end of the array implied by
1723 a static type (though there are restrictions on indexing beyond the bounds
1724 of an allocated object in some cases). This means that single-dimension
1725 'variable sized array' addressing can be implemented in LLVM with a zero
1726 length array type. An implementation of 'pascal style arrays' in LLVM could
1727 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1728
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1735
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1737<p>The function type can be thought of as a function signature. It consists of
1738 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1739 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1740
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1742<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1743 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1744</pre>
1745
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1746<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]1747 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1748 which indicates that the function takes a variable number of arguments.
1749 Variable argument functions can access their arguments with
1750 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1751 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1752 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1755<table class="layout">
1756 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1757 <td class="left"><tt>i32 (i32)</tt></td>
1758 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1759 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1760 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1761 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1762 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1763 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1764 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1765 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1766 </td>
1767 </tr><tr class="layout">
1768 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1769 <td class="left">A vararg function that takes at least one
1770 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1771 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1772 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1774 </tr><tr class="layout">
1775 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1776 <td class="left">A function taking an <tt>i32</tt>, returning a
1777 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1778 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1781
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1782</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1790<p>The structure type is used to represent a collection of data members together
1791 in memory. The packing of the field types is defined to match the ABI of the
1792 underlying processor. The elements of a structure may be any type that has a
1793 size.</p>
1794
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1795<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1796 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1797 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Structures in registers are accessed using the
1799 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1800 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1802<pre>
1803 { &lt;type list&gt; }
1804</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1807<table class="layout">
1808 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1809 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1810 <td class="left">A triple of three <tt>i32</tt> values</td>
1811 </tr><tr class="layout">
1812 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1817 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1820</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1824</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1825
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1826<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1828<h5>Overview:</h5>
1829<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1830 together in memory. There is no padding between fields. Further, the
1831 alignment of a packed structure is 1 byte. The elements of a packed
1832 structure may be any type that has a size.</p>
1833
1834<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1835 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1836 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1837
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt; { &lt;type list&gt; } &gt;
1841</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1843<h5>Examples:</h5>
1844<table class="layout">
1845 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1846 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1847 <td class="left">A triple of three <tt>i32</tt> values</td>
1848 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1849 <td class="left">
1850<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1851 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1852 second element is a <a href="#t_pointer">pointer</a> to a
1853 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1854 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855 </tr>
1856</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1858</div>
1859
1860<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1863<div class="doc_text">
1864
1865<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1866<p>The pointer type is used to specify memory locations.
1867 Pointers are commonly used to reference objects in memory.</p>
1868
1869<p>Pointer types may have an optional address space attribute defining the
1870 numbered address space where the pointed-to object resides. The default
1871 address space is number zero. The semantics of non-zero address
1872 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1873
1874<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1875 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1876
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1877<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1878<pre>
1879 &lt;type&gt; *
1880</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1882<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1883<table class="layout">
1884 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1885 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1886 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1887 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1888 </tr>
1889 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1890 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1891 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1892 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1893 <tt>i32</tt>.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1897 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1898 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1899 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1900</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1902</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1903
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1907<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1908
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910<p>A vector type is a simple derived type that represents a vector of elements.
1911 Vector types are used when multiple primitive data are operated in parallel
1912 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1913 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1915
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1917<pre>
1918 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1919</pre>
1920
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1921<p>The number of elements is a constant integer value larger than 0; elementtype
1922 may be any integer or floating point type. Vectors of size zero are not
1923 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1924
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1925<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1926<table class="layout">
1927 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1928 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1929 <td class="left">Vector of 4 32-bit integer values.</td>
1930 </tr>
1931 <tr class="layout">
1932 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1933 <td class="left">Vector of 8 32-bit floating-point values.</td>
1934 </tr>
1935 <tr class="layout">
1936 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1937 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938 </tr>
1939</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1940
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941</div>
1942
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943<!-- _______________________________________________________________________ -->
1944<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1945<div class="doc_text">
1946
1947<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1948<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1949 corresponds (for example) to the C notion of a forward declared structure
1950 type. In LLVM, opaque types can eventually be resolved to any type (not just
1951 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1952
1953<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1954<pre>
1955 opaque
1956</pre>
1957
1958<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1959<table class="layout">
1960 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>opaque</tt></td>
1962 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1963 </tr>
1964</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1965
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966</div>
1967
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1968<!-- ======================================================================= -->
1969<div class="doc_subsection">
1970 <a name="t_uprefs">Type Up-references</a>
1971</div>
1972
1973<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1974
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976<p>An "up reference" allows you to refer to a lexically enclosing type without
1977 requiring it to have a name. For instance, a structure declaration may
1978 contain a pointer to any of the types it is lexically a member of. Example
1979 of up references (with their equivalent as named type declarations)
1980 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1981
1982<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1983 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1984 { \2 }* %y = type { %y }*
1985 \1* %z = type %z*
1986</pre>
1987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An up reference is needed by the asmprinter for printing out cyclic types
1989 when there is no declared name for a type in the cycle. Because the
1990 asmprinter does not want to print out an infinite type string, it needs a
1991 syntax to handle recursive types that have no names (all names are optional
1992 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<h5>Syntax:</h5>
1995<pre>
1996 \&lt;level&gt;
1997</pre>
1998
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1999<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]2000
2001<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
2004 <td class="left"><tt>\1*</tt></td>
2005 <td class="left">Self-referential pointer.</td>
2006 </tr>
2007 <tr class="layout">
2008 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2009 <td class="left">Recursive structure where the upref refers to the out-most
2010 structure.</td>
2011 </tr>
2012</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2014</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2015
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<!-- *********************************************************************** -->
2017<div class="doc_section"> <a name="constants">Constants</a> </div>
2018<!-- *********************************************************************** -->
2019
2020<div class="doc_text">
2021
2022<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2023 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2024
2025</div>
2026
2027<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2028<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2029
2030<div class="doc_text">
2031
2032<dl>
2033 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2034 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2035 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038 <dd>Standard integers (such as '4') are constants of
2039 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2040 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2045 notation (see below). The assembler requires the exact decimal value of a
2046 floating-point constant. For example, the assembler accepts 1.25 but
2047 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2048 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2049
2050 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2051 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2052 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053</dl>
2054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2055<p>The one non-intuitive notation for constants is the hexadecimal form of
2056 floating point constants. For example, the form '<tt>double
2057 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2058 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2059 constants are required (and the only time that they are generated by the
2060 disassembler) is when a floating point constant must be emitted but it cannot
2061 be represented as a decimal floating point number in a reasonable number of
2062 digits. For example, NaN's, infinities, and other special values are
2063 represented in their IEEE hexadecimal format so that assembly and disassembly
2064 do not cause any bits to change in the constants.</p>
2065
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2066<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2067 represented using the 16-digit form shown above (which matches the IEEE754
2068 representation for double); float values must, however, be exactly
2069 representable as IEE754 single precision. Hexadecimal format is always used
2070 for long double, and there are three forms of long double. The 80-bit format
2071 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2072 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2073 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2074 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2075 currently supported target uses this format. Long doubles will only work if
2076 they match the long double format on your target. All hexadecimal formats
2077 are big-endian (sign bit at the left).</p>
2078
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2079<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2080</div>
2081
2082<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2083<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2084<a name="aggregateconstants"></a> <!-- old anchor -->
2085<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2086</div>
2087
2088<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2090<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2091 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2092
2093<dl>
2094 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2095 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2096 type definitions (a comma separated list of elements, surrounded by braces
2097 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2098 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2099 Structure constants must have <a href="#t_struct">structure type</a>, and
2100 the number and types of elements must match those specified by the
2101 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2102
2103 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2104 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2105 definitions (a comma separated list of elements, surrounded by square
2106 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2107 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2108 the number and types of elements must match those specified by the
2109 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2110
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2111 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2112 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113 definitions (a comma separated list of elements, surrounded by
2114 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2115 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2116 have <a href="#t_vector">vector type</a>, and the number and types of
2117 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2118
2119 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2121 value to zero of <em>any</em> type, including scalar and
2122 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2123 This is often used to avoid having to print large zero initializers
2124 (e.g. for large arrays) and is always exactly equivalent to using explicit
2125 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2126
2127 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2128 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2129 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2130 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2131 be interpreted as part of the instruction stream, metadata is a place to
2132 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2133</dl>
2134
2135</div>
2136
2137<!-- ======================================================================= -->
2138<div class="doc_subsection">
2139 <a name="globalconstants">Global Variable and Function Addresses</a>
2140</div>
2141
2142<div class="doc_text">
2143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2144<p>The addresses of <a href="#globalvars">global variables</a>
2145 and <a href="#functionstructure">functions</a> are always implicitly valid
2146 (link-time) constants. These constants are explicitly referenced when
2147 the <a href="#identifiers">identifier for the global</a> is used and always
2148 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2149 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2150
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2151<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2152@X = global i32 17
2153@Y = global i32 42
2154@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2155</pre>
2156
2157</div>
2158
2159<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2160<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2161<div class="doc_text">
2162
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2163<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]2164 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2165 Undefined values may be of any type (other than '<tt>label</tt>'
2166 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2168<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2169 program is well defined no matter what value is used. This gives the
2170 compiler more freedom to optimize. Here are some examples of (potentially
2171 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2172
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2173
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2174<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2175 %A = add %X, undef
2176 %B = sub %X, undef
2177 %C = xor %X, undef
2178Safe:
2179 %A = undef
2180 %B = undef
2181 %C = undef
2182</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2183
2184<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2185 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2187<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 %A = or %X, undef
2189 %B = and %X, undef
2190Safe:
2191 %A = -1
2192 %B = 0
2193Unsafe:
2194 %A = undef
2195 %B = undef
2196</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2197
2198<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2199 For example, if <tt>%X</tt> has a zero bit, then the output of the
2200 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2201 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2202 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2203 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2204 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2205 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2206 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2207
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2208<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2209 %A = select undef, %X, %Y
2210 %B = select undef, 42, %Y
2211 %C = select %X, %Y, undef
2212Safe:
2213 %A = %X (or %Y)
2214 %B = 42 (or %Y)
2215 %C = %Y
2216Unsafe:
2217 %A = undef
2218 %B = undef
2219 %C = undef
2220</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2221
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2222<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2223 branch) conditions can go <em>either way</em>, but they have to come from one
2224 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2225 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2226 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2227 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2228 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2229 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2230
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2231<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2232 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2233
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2234 %B = undef
2235 %C = xor %B, %B
2236
2237 %D = undef
2238 %E = icmp lt %D, 4
2239 %F = icmp gte %D, 4
2240
2241Safe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245 %D = undef
2246 %E = undef
2247 %F = undef
2248</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2250<p>This example points out that two '<tt>undef</tt>' operands are not
2251 necessarily the same. This can be surprising to people (and also matches C
2252 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2253 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2254 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2255 its value over its "live range". This is true because the variable doesn't
2256 actually <em>have a live range</em>. Instead, the value is logically read
2257 from arbitrary registers that happen to be around when needed, so the value
2258 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2259 need to have the same semantics or the core LLVM "replace all uses with"
2260 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2261
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2262<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2263 %A = fdiv undef, %X
2264 %B = fdiv %X, undef
2265Safe:
2266 %A = undef
2267b: unreachable
2268</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2269
2270<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2271 value</em> and <em>undefined behavior</em>. An undefined value (like
2272 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2273 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2274 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2275 defined on SNaN's. However, in the second example, we can make a more
2276 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2277 arbitrary value, we are allowed to assume that it could be zero. Since a
2278 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2279 the operation does not execute at all. This allows us to delete the divide and
2280 all code after it. Because the undefined operation "can't happen", the
2281 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2282
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2283<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2284a: store undef -> %X
2285b: store %X -> undef
2286Safe:
2287a: &lt;deleted&gt;
2288b: unreachable
2289</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2290
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2291<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2292 undefined value can be assumed to not have any effect; we can assume that the
2293 value is overwritten with bits that happen to match what was already there.
2294 However, a store <em>to</em> an undefined location could clobber arbitrary
2295 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2296
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2297</div>
2298
2299<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2300<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2301<div class="doc_text">
2302
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2303<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2304 instead of representing an unspecified bit pattern, they represent the
2305 fact that an instruction or constant expression which cannot evoke side
2306 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2307 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2308
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2309<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]2310 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2311 <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]2312
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2313<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2314
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2315<ul>
2316<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2317 their operands.</li>
2318
2319<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2320 to their dynamic predecessor basic block.</li>
2321
2322<li>Function arguments depend on the corresponding actual argument values in
2323 the dynamic callers of their functions.</li>
2324
2325<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2326 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2327 control back to them.</li>
2328
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2329<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2330 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2331 or exception-throwing call instructions that dynamically transfer control
2332 back to them.</li>
2333
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2334<li>Non-volatile loads and stores depend on the most recent stores to all of the
2335 referenced memory addresses, following the order in the IR
2336 (including loads and stores implied by intrinsics such as
2337 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2338
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2339<!-- TODO: In the case of multiple threads, this only applies if the store
2340 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2341
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2342<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2343
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2344<li>An instruction with externally visible side effects depends on the most
2345 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2346 the order in the IR. (This includes
2347 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2348
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2349<li>An instruction <i>control-depends</i> on a
2350 <a href="#terminators">terminator instruction</a>
2351 if the terminator instruction has multiple successors and the instruction
2352 is always executed when control transfers to one of the successors, and
2353 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2354
2355<li>Dependence is transitive.</li>
2356
2357</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2358
2359<p>Whenever a trap value is generated, all values which depend on it evaluate
2360 to trap. If they have side effects, the evoke their side effects as if each
2361 operand with a trap value were undef. If they have externally-visible side
2362 effects, the behavior is undefined.</p>
2363
2364<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2365
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2366<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2367entry:
2368 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2369 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2370 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2371 store i32 0, i32* %trap_yet_again ; undefined behavior
2372
2373 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2374 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2375
2376 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2377
2378 %narrowaddr = bitcast i32* @g to i16*
2379 %wideaddr = bitcast i32* @g to i64*
2380 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2381 %trap4 = load i64* %widaddr ; Returns a trap value.
2382
2383 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2384 %br i1 %cmp, %true, %end ; Branch to either destination.
2385
2386true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2387 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2388 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2389 br label %end
2390
2391end:
2392 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2393 ; Both edges into this PHI are
2394 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2395 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2396
2397 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2398 ; so this is defined (ignoring earlier
2399 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2400</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2401
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2402</div>
2403
2404<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2405<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2406 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2407<div class="doc_text">
2408
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2409<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2410
2411<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2412 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2413 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2414
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2415<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2416 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2417 comparisons against null. Pointer equality tests between labels addresses
2418 results in undefined behavior &mdash; though, again, comparison against null
2419 is ok, and no label is equal to the null pointer. This may be passed around
2420 as an opaque pointer sized value as long as the bits are not inspected. This
2421 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2422 long as the original value is reconstituted before the <tt>indirectbr</tt>
2423 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2424
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2425<p>Finally, some targets may provide defined semantics when using the value as
2426 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2427
2428</div>
2429
2430
2431<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2432<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2433</div>
2434
2435<div class="doc_text">
2436
2437<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2438 to be used as constants. Constant expressions may be of
2439 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2440 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2441 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2442
2443<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2444 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2445 <dd>Truncate a constant to another type. The bit size of CST must be larger
2446 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2447
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2448 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2449 <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]2450 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2451
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2452 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2453 <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]2454 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2455
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2456 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Truncate a floating point constant to another floating point type. The
2458 size of CST must be larger than the size of TYPE. Both types must be
2459 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2460
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2461 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Floating point extend a constant to another type. The size of CST must be
2463 smaller or equal to the size of TYPE. Both types must be floating
2464 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2465
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2466 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2467 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2468 constant. TYPE must be a scalar or vector integer type. CST must be of
2469 scalar or vector floating point type. Both CST and TYPE must be scalars,
2470 or vectors of the same number of elements. If the value won't fit in the
2471 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2472
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2473 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2474 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2475 constant. TYPE must be a scalar or vector integer type. CST must be of
2476 scalar or vector floating point type. Both CST and TYPE must be scalars,
2477 or vectors of the same number of elements. If the value won't fit in the
2478 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2479
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2480 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2481 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2482 constant. TYPE must be a scalar or vector floating point type. CST must be
2483 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2484 vectors of the same number of elements. If the value won't fit in the
2485 floating point type, the results are undefined.</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>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2489 constant. TYPE must be a scalar or vector floating point type. CST must be
2490 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2491 vectors of the same number of elements. If the value won't fit in the
2492 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2495 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2497 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2498 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2499
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2502 type. CST must be of integer type. The CST value is zero extended,
2503 truncated, or unchanged to make it fit in a pointer size. This one is
2504 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2505
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2507 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2508 are the same as those for the <a href="#i_bitcast">bitcast
2509 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2510
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2512 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2513 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2514 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2515 instruction, the index list may have zero or more indexes, which are
2516 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2517
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2519 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2520
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2521 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2522 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2523
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2525 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2526
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2527 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2529 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2530
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2531 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2533 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2534
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2535 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2537 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2538
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2539 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2540 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2541 constants. The index list is interpreted in a similar manner as indices in
2542 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2543 index value must be specified.</dd>
2544
2545 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2546 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2547 constants. The index list is interpreted in a similar manner as indices in
2548 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2549 index value must be specified.</dd>
2550
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2551 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2553 be any of the <a href="#binaryops">binary</a>
2554 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2555 on operands are the same as those for the corresponding instruction
2556 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2557</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2558
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2559</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2560
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2561<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2562<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2563<!-- *********************************************************************** -->
2564
2565<!-- ======================================================================= -->
2566<div class="doc_subsection">
2567<a name="inlineasm">Inline Assembler Expressions</a>
2568</div>
2569
2570<div class="doc_text">
2571
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2572<p>LLVM supports inline assembler expressions (as opposed
2573 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2574 a special value. This value represents the inline assembler as a string
2575 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2576 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2577 expression has side effects, and a flag indicating whether the function
2578 containing the asm needs to align its stack conservatively. An example
2579 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2580
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2581<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2582i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2583</pre>
2584
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2586 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2587 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2588
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2589<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2590%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]2591</pre>
2592
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2593<p>Inline asms with side effects not visible in the constraint list must be
2594 marked as having side effects. This is done through the use of the
2595 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2596
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2597<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2598call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2599</pre>
2600
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2601<p>In some cases inline asms will contain code that will not work unless the
2602 stack is aligned in some way, such as calls or SSE instructions on x86,
2603 yet will not contain code that does that alignment within the asm.
2604 The compiler should make conservative assumptions about what the asm might
2605 contain and should generate its usual stack alignment code in the prologue
2606 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2607
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2608<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2609call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2610</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2611
2612<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2613 first.</p>
2614
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2615<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2616 documented here. Constraints on what can be done (e.g. duplication, moving,
2617 etc need to be documented). This is probably best done by reference to
2618 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2619</div>
2620
2621<div class="doc_subsubsection">
2622<a name="inlineasm_md">Inline Asm Metadata</a>
2623</div>
2624
2625<div class="doc_text">
2626
2627<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2628 attached to it that contains a list of constant integers. If present, the
2629 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2630 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2631 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2632 source code that produced it. For example:</p>
2633
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2634<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2635call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2636...
2637!42 = !{ i32 1234567 }
2638</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2639
2640<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2641 IR. If the MDNode contains multiple constants, the code generator will use
2642 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2643
2644</div>
2645
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2646<!-- ======================================================================= -->
2647<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2648 Strings</a>
2649</div>
2650
2651<div class="doc_text">
2652
2653<p>LLVM IR allows metadata to be attached to instructions in the program that
2654 can convey extra information about the code to the optimizers and code
2655 generator. One example application of metadata is source-level debug
2656 information. There are two metadata primitives: strings and nodes. All
2657 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2658 preceding exclamation point ('<tt>!</tt>').</p>
2659
2660<p>A metadata string is a string surrounded by double quotes. It can contain
2661 any character by escaping non-printable characters with "\xx" where "xx" is
2662 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2663
2664<p>Metadata nodes are represented with notation similar to structure constants
2665 (a comma separated list of elements, surrounded by braces and preceded by an
2666 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2667 10}</tt>". Metadata nodes can have any values as their operand.</p>
2668
2669<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2670 metadata nodes, which can be looked up in the module symbol table. For
2671 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2672
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2673<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2674 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2675
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2676 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2677 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2678 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2679
2680<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2681 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2682
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2683 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2684 %indvar.next = add i64 %indvar, 1, !dbg !21
2685 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2686</div>
2687
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2688
2689<!-- *********************************************************************** -->
2690<div class="doc_section">
2691 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2692</div>
2693<!-- *********************************************************************** -->
2694
2695<p>LLVM has a number of "magic" global variables that contain data that affect
2696code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2697of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2698section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2699by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2700
2701<!-- ======================================================================= -->
2702<div class="doc_subsection">
2703<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2704</div>
2705
2706<div class="doc_text">
2707
2708<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2709href="#linkage_appending">appending linkage</a>. This array contains a list of
2710pointers to global variables and functions which may optionally have a pointer
2711cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2712
2713<pre>
2714 @X = global i8 4
2715 @Y = global i32 123
2716
2717 @llvm.used = appending global [2 x i8*] [
2718 i8* @X,
2719 i8* bitcast (i32* @Y to i8*)
2720 ], section "llvm.metadata"
2721</pre>
2722
2723<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2724compiler, assembler, and linker are required to treat the symbol as if there is
2725a reference to the global that it cannot see. For example, if a variable has
2726internal linkage and no references other than that from the <tt>@llvm.used</tt>
2727list, it cannot be deleted. This is commonly used to represent references from
2728inline asms and other things the compiler cannot "see", and corresponds to
2729"attribute((used))" in GNU C.</p>
2730
2731<p>On some targets, the code generator must emit a directive to the assembler or
2732object file to prevent the assembler and linker from molesting the symbol.</p>
2733
2734</div>
2735
2736<!-- ======================================================================= -->
2737<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2738<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2739</div>
2740
2741<div class="doc_text">
2742
2743<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2744<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2745touching the symbol. On targets that support it, this allows an intelligent
2746linker to optimize references to the symbol without being impeded as it would be
2747by <tt>@llvm.used</tt>.</p>
2748
2749<p>This is a rare construct that should only be used in rare circumstances, and
2750should not be exposed to source languages.</p>
2751
2752</div>
2753
2754<!-- ======================================================================= -->
2755<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2756<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2757</div>
2758
2759<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2760<pre>
2761%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2762@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2763</pre>
2764<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.
2765</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2766
2767</div>
2768
2769<!-- ======================================================================= -->
2770<div class="doc_subsection">
2771<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2772</div>
2773
2774<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2775<pre>
2776%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2777@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2778</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2779
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2780<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.
2781</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2782
2783</div>
2784
2785
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2786<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2787<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2788<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2789
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2790<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2792<p>The LLVM instruction set consists of several different classifications of
2793 instructions: <a href="#terminators">terminator
2794 instructions</a>, <a href="#binaryops">binary instructions</a>,
2795 <a href="#bitwiseops">bitwise binary instructions</a>,
2796 <a href="#memoryops">memory instructions</a>, and
2797 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2799</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2801<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2802<div class="doc_subsection"> <a name="terminators">Terminator
2803Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2804
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2805<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2807<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2808 in a program ends with a "Terminator" instruction, which indicates which
2809 block should be executed after the current block is finished. These
2810 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2811 control flow, not values (the one exception being the
2812 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2813
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2814<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2816 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2817 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2818 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2820 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2821 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2827Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2832<pre>
2833 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]2834 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2835</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2836
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2837<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2839 a value) from a function back to the caller.</p>
2840
2841<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2842 value and then causes control flow, and one that just causes control flow to
2843 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2845<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2846<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2847 return value. The type of the return value must be a
2848 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2850<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2851 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2852 value or a return value with a type that does not match its type, or if it
2853 has a void return type and contains a '<tt>ret</tt>' instruction with a
2854 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2856<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2857<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2858 the calling function's context. If the caller is a
2859 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2860 instruction after the call. If the caller was an
2861 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2862 the beginning of the "normal" destination block. If the instruction returns
2863 a value, that value shall set the call or invoke instruction's return
2864 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2866<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2867<pre>
2868 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2869 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2870 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]2871</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2872
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2873</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2874<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2875<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2877<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2878
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2879<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880<pre>
2881 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]2882</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2885<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2886 different basic block in the current function. There are two forms of this
2887 instruction, corresponding to a conditional branch and an unconditional
2888 branch.</p>
2889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2891<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2892 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2893 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2894 target.</p>
2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2897<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2899 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2900 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2902<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2903<pre>
2904Test:
2905 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2906 br i1 %cond, label %IfEqual, label %IfUnequal
2907IfEqual:
2908 <a href="#i_ret">ret</a> i32 1
2909IfUnequal:
2910 <a href="#i_ret">ret</a> i32 0
2911</pre>
2912
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2913</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2914
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2915<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2916<div class="doc_subsubsection">
2917 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2918</div>
2919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2920<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2921
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2923<pre>
2924 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2925</pre>
2926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2928<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]2929 several different places. It is a generalization of the '<tt>br</tt>'
2930 instruction, allowing a branch to occur to one of many possible
2931 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2933<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2934<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2935 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2936 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2937 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2938
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2939<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2940<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2941 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2942 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2943 transferred to the corresponding destination; otherwise, control flow is
2944 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2945
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2946<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2947<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2948 <tt>switch</tt> instruction, this instruction may be code generated in
2949 different ways. For example, it could be generated as a series of chained
2950 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951
2952<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2953<pre>
2954 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2955 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2956 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2957
2958 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2959 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2960
2961 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2962 switch i32 %val, label %otherwise [ i32 0, label %onzero
2963 i32 1, label %onone
2964 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2965</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2967</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2968
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2969
2970<!-- _______________________________________________________________________ -->
2971<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2972 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2973</div>
2974
2975<div class="doc_text">
2976
2977<h5>Syntax:</h5>
2978<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2979 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]2980</pre>
2981
2982<h5>Overview:</h5>
2983
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2984<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2985 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2986 "<tt>address</tt>". Address must be derived from a <a
2987 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2988
2989<h5>Arguments:</h5>
2990
2991<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2992 rest of the arguments indicate the full set of possible destinations that the
2993 address may point to. Blocks are allowed to occur multiple times in the
2994 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2995
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2996<p>This destination list is required so that dataflow analysis has an accurate
2997 understanding of the CFG.</p>
2998
2999<h5>Semantics:</h5>
3000
3001<p>Control transfers to the block specified in the address argument. All
3002 possible destination blocks must be listed in the label list, otherwise this
3003 instruction has undefined behavior. This implies that jumps to labels
3004 defined in other functions have undefined behavior as well.</p>
3005
3006<h5>Implementation:</h5>
3007
3008<p>This is typically implemented with a jump through a register.</p>
3009
3010<h5>Example:</h5>
3011<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3012 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3013</pre>
3014
3015</div>
3016
3017
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3018<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3019<div class="doc_subsubsection">
3020 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3021</div>
3022
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3023<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3025<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3026<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3027 &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]3028 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3029</pre>
3030
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3031<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3032<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3033 function, with the possibility of control flow transfer to either the
3034 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3035 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3036 control flow will return to the "normal" label. If the callee (or any
3037 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3038 instruction, control is interrupted and continued at the dynamically nearest
3039 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3040
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3041<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3042<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3044<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3045 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3046 convention</a> the call should use. If none is specified, the call
3047 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3048
3049 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3050 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3051 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3052
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3053 <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]3054 function value being invoked. In most cases, this is a direct function
3055 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3056 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3057
3058 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3059 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3060
3061 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3062 signature argument types and parameter attributes. All arguments must be
3063 of <a href="#t_firstclass">first class</a> type. If the function
3064 signature indicates the function accepts a variable number of arguments,
3065 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3066
3067 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3069
3070 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3071 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3072
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3073 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3074 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3075 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3076</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3077
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3078<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3079<p>This instruction is designed to operate as a standard
3080 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3081 primary difference is that it establishes an association with a label, which
3082 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3083
3084<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3086 exception. Additionally, this is important for implementation of
3087 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089<p>For the purposes of the SSA form, the definition of the value returned by the
3090 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3091 block to the "normal" label. If the callee unwinds then no return value is
3092 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3093
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3094<p>Note that the code generator does not yet completely support unwind, and
3095that the invoke/unwind semantics are likely to change in future versions.</p>
3096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3097<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3098<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3099 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3100 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3101 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3102 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3103</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3105</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3106
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3107<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3108
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3109<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3110Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3111
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3112<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3113
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3114<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3115<pre>
3116 unwind
3117</pre>
3118
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3119<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3120<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3121 at the first callee in the dynamic call stack which used
3122 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3123 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3124
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3125<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3126<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127 immediately halt. The dynamic call stack is then searched for the
3128 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3129 Once found, execution continues at the "exceptional" destination block
3130 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3131 instruction in the dynamic call chain, undefined behavior results.</p>
3132
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3133<p>Note that the code generator does not yet completely support unwind, and
3134that the invoke/unwind semantics are likely to change in future versions.</p>
3135
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3136</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3137
3138<!-- _______________________________________________________________________ -->
3139
3140<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3141Instruction</a> </div>
3142
3143<div class="doc_text">
3144
3145<h5>Syntax:</h5>
3146<pre>
3147 unreachable
3148</pre>
3149
3150<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3151<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152 instruction is used to inform the optimizer that a particular portion of the
3153 code is not reachable. This can be used to indicate that the code after a
3154 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3155
3156<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3157<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3158
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3159</div>
3160
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3161<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3162<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3163
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3164<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165
3166<p>Binary operators are used to do most of the computation in a program. They
3167 require two operands of the same type, execute an operation on them, and
3168 produce a single value. The operands might represent multiple data, as is
3169 the case with the <a href="#t_vector">vector</a> data type. The result value
3170 has the same type as its operands.</p>
3171
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3172<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3174</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3175
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3176<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3177<div class="doc_subsubsection">
3178 <a name="i_add">'<tt>add</tt>' Instruction</a>
3179</div>
3180
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3181<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3183<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3184<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3185 &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]3186 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3187 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3188 &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]3189</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3190
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3191<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3192<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3193
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3194<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195<p>The two arguments to the '<tt>add</tt>' instruction must
3196 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3197 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3199<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3200<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202<p>If the sum has unsigned overflow, the result returned is the mathematical
3203 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]3204
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205<p>Because LLVM integers use a two's complement representation, this instruction
3206 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3207
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3208<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3209 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3210 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3211 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3212 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3213
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3214<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3215<pre>
3216 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3217</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3219</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3222<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3223 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3224</div>
3225
3226<div class="doc_text">
3227
3228<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3229<pre>
3230 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3231</pre>
3232
3233<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3234<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3235
3236<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3237<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3238 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3239 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3240
3241<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3242<p>The value produced is the floating point sum of the two operands.</p>
3243
3244<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3247</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3248
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3249</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3253 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3254</div>
3255
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3256<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3259<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3260 &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]3261 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3262 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3263 &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]3264</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3265
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3266<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3267<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3269
3270<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3271 '<tt>neg</tt>' instruction present in most other intermediate
3272 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3273
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3274<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3275<p>The two arguments to the '<tt>sub</tt>' instruction must
3276 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3277 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3278
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3279<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3280<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3281
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3282<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3283 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3284 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286<p>Because LLVM integers use a two's complement representation, this instruction
3287 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3288
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3289<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3290 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3291 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3292 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3293 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3296<pre>
3297 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3298 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3299</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3300
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3301</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3302
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3303<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3304<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3305 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3306</div>
3307
3308<div class="doc_text">
3309
3310<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3311<pre>
3312 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3313</pre>
3314
3315<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3316<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318
3319<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320 '<tt>fneg</tt>' instruction present in most other intermediate
3321 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3322
3323<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3324<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3325 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3326 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3327
3328<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3329<p>The value produced is the floating point difference of the two operands.</p>
3330
3331<h5>Example:</h5>
3332<pre>
3333 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3334 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3335</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3336
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3337</div>
3338
3339<!-- _______________________________________________________________________ -->
3340<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3341 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3342</div>
3343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3344<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3346<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3348 &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]3349 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3350 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3351 &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]3352</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3354<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3356
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3357<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358<p>The two arguments to the '<tt>mul</tt>' instruction must
3359 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3360 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3362<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3363<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3364
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3365<p>If the result of the multiplication has unsigned overflow, the result
3366 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3367 width of the result.</p>
3368
3369<p>Because LLVM integers use a two's complement representation, and the result
3370 is the same width as the operands, this instruction returns the correct
3371 result for both signed and unsigned integers. If a full product
3372 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3373 be sign-extended or zero-extended as appropriate to the width of the full
3374 product.</p>
3375
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3376<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3377 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3378 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3379 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3380 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3381
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3382<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383<pre>
3384 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3385</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3386
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3387</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3389<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3390<div class="doc_subsubsection">
3391 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3392</div>
3393
3394<div class="doc_text">
3395
3396<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397<pre>
3398 &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]3399</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3400
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3401<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3403
3404<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3405<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3406 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3407 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3408
3409<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3410<p>The value produced is the floating point product of the two operands.</p>
3411
3412<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &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]3415</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3416
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3417</div>
3418
3419<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3420<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3421</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3423<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3424
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3425<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426<pre>
3427 &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]3428</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3430<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3431<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3432
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3433<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3434<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3435 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3436 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3437
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3438<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3439<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3441<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3443
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3444<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3445
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3446<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447<pre>
3448 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3449</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3451</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<!-- _______________________________________________________________________ -->
3454<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3455</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3457<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3459<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3460<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3461 &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]3462 &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]3463</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3464
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3465<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3466<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3467
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3469<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3471 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3472
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3473<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474<p>The value produced is the signed integer quotient of the two operands rounded
3475 towards zero.</p>
3476
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3477<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3479
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3480<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3481 undefined behavior; this is a rare case, but can occur, for example, by doing
3482 a 32-bit division of -2147483648 by -1.</p>
3483
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3484<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3485 <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]3486 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3487
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3488<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489<pre>
3490 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3491</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3492
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3493</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495<!-- _______________________________________________________________________ -->
3496<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3497Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3499<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3503 &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]3504</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3505
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506<h5>Overview:</h5>
3507<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3508
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3509<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3510<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3512 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3513
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3514<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3515<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3516
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3517<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3518<pre>
3519 &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]3520</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3522</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3523
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3524<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3525<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3526</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3528<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3529
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3530<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531<pre>
3532 &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]3533</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3535<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3537 division of its two arguments.</p>
3538
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3539<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3540<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3542 values. Both arguments must have identical types.</p>
3543
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3544<h5>Semantics:</h5>
3545<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3546 This instruction always performs an unsigned division to get the
3547 remainder.</p>
3548
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3549<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3551
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3552<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3553
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3554<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555<pre>
3556 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3557</pre>
3558
3559</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3560
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3561<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3562<div class="doc_subsubsection">
3563 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3564</div>
3565
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3566<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3567
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3568<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3570 &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]3571</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3572
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3573<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3574<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3575 division of its two operands. This instruction can also take
3576 <a href="#t_vector">vector</a> versions of the values in which case the
3577 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3578
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3579<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3580<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3581 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3582 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3583
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3584<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3585<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3587 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3588 a value. For more information about the difference,
3589 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3590 Math Forum</a>. For a table of how this is implemented in various languages,
3591 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3592 Wikipedia: modulo operation</a>.</p>
3593
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3594<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3595 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3596
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3597<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598 Overflow also leads to undefined behavior; this is a rare case, but can
3599 occur, for example, by taking the remainder of a 32-bit division of
3600 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3601 lets srem be implemented using instructions that return both the result of
3602 the division and the remainder.)</p>
3603
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3604<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3605<pre>
3606 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3607</pre>
3608
3609</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612<div class="doc_subsubsection">
3613 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3614
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3615<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3616
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3617<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618<pre>
3619 &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]3620</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3621
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3622<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3623<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3624 its two operands.</p>
3625
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3626<h5>Arguments:</h5>
3627<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3628 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3629 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3630
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3631<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3632<p>This instruction returns the <i>remainder</i> of a division. The remainder
3633 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3634
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3635<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3636<pre>
3637 &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]3638</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3640</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3641
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3642<!-- ======================================================================= -->
3643<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3644Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3645
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3646<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3647
3648<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3649 program. They are generally very efficient instructions and can commonly be
3650 strength reduced from other instructions. They require two operands of the
3651 same type, execute an operation on them, and produce a single value. The
3652 resulting value is the same type as its operands.</p>
3653
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3654</div>
3655
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3656<!-- _______________________________________________________________________ -->
3657<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3658Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3660<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3662<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663<pre>
3664 &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]3665</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3666
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3667<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3669 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3670
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3671<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3672<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3673 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3674 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3675
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3676<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3678 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3679 is (statically or dynamically) negative or equal to or larger than the number
3680 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3681 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3682 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3683
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684<h5>Example:</h5>
3685<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3686 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3687 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3688 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3689 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3690 &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]3691</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3693</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695<!-- _______________________________________________________________________ -->
3696<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3697Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3699<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702<pre>
3703 &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]3704</pre>
3705
3706<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3708 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3709
3710<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3711<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3713 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3714
3715<h5>Semantics:</h5>
3716<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3717 significant bits of the result will be filled with zero bits after the shift.
3718 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3719 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3720 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3721 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3722
3723<h5>Example:</h5>
3724<pre>
3725 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3726 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3727 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3728 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3729 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3730 &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]3731</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3733</div>
3734
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3735<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3736<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3737Instruction</a> </div>
3738<div class="doc_text">
3739
3740<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741<pre>
3742 &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]3743</pre>
3744
3745<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3747 operand shifted to the right a specified number of bits with sign
3748 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3749
3750<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3751<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3752 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3753 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3754
3755<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756<p>This instruction always performs an arithmetic shift right operation, The
3757 most significant bits of the result will be filled with the sign bit
3758 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3759 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3760 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3761 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3762
3763<h5>Example:</h5>
3764<pre>
3765 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3766 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3767 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3768 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3769 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3770 &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]3771</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3773</div>
3774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3775<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3776<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3777Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3779<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3781<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3782<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3783 &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]3784</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3786<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3788 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3790<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3791<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3792 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3793 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3795<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3796<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3799 <tbody>
3800 <tr>
3801 <td>In0</td>
3802 <td>In1</td>
3803 <td>Out</td>
3804 </tr>
3805 <tr>
3806 <td>0</td>
3807 <td>0</td>
3808 <td>0</td>
3809 </tr>
3810 <tr>
3811 <td>0</td>
3812 <td>1</td>
3813 <td>0</td>
3814 </tr>
3815 <tr>
3816 <td>1</td>
3817 <td>0</td>
3818 <td>0</td>
3819 </tr>
3820 <tr>
3821 <td>1</td>
3822 <td>1</td>
3823 <td>1</td>
3824 </tr>
3825 </tbody>
3826</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3828<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3829<pre>
3830 &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]3831 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3832 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3833</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3834</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3835<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3836<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838<div class="doc_text">
3839
3840<h5>Syntax:</h5>
3841<pre>
3842 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3843</pre>
3844
3845<h5>Overview:</h5>
3846<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3847 two operands.</p>
3848
3849<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3850<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3851 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3852 values. Both arguments must have identical types.</p>
3853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3854<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3855<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3856
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3857<table border="1" cellspacing="0" cellpadding="4">
3858 <tbody>
3859 <tr>
3860 <td>In0</td>
3861 <td>In1</td>
3862 <td>Out</td>
3863 </tr>
3864 <tr>
3865 <td>0</td>
3866 <td>0</td>
3867 <td>0</td>
3868 </tr>
3869 <tr>
3870 <td>0</td>
3871 <td>1</td>
3872 <td>1</td>
3873 </tr>
3874 <tr>
3875 <td>1</td>
3876 <td>0</td>
3877 <td>1</td>
3878 </tr>
3879 <tr>
3880 <td>1</td>
3881 <td>1</td>
3882 <td>1</td>
3883 </tr>
3884 </tbody>
3885</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3887<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3888<pre>
3889 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3890 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3891 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3892</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3894</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3896<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3897<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3898Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3899
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3900<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903<pre>
3904 &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]3905</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3909 its two operands. The <tt>xor</tt> is used to implement the "one's
3910 complement" operation, which is the "~" operator in C.</p>
3911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3912<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3913<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3915 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3918<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3920<table border="1" cellspacing="0" cellpadding="4">
3921 <tbody>
3922 <tr>
3923 <td>In0</td>
3924 <td>In1</td>
3925 <td>Out</td>
3926 </tr>
3927 <tr>
3928 <td>0</td>
3929 <td>0</td>
3930 <td>0</td>
3931 </tr>
3932 <tr>
3933 <td>0</td>
3934 <td>1</td>
3935 <td>1</td>
3936 </tr>
3937 <tr>
3938 <td>1</td>
3939 <td>0</td>
3940 <td>1</td>
3941 </tr>
3942 <tr>
3943 <td>1</td>
3944 <td>1</td>
3945 <td>0</td>
3946 </tr>
3947 </tbody>
3948</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3950<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951<pre>
3952 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3953 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3954 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3955 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3956</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3958</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3960<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3961<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3962 <a name="vectorops">Vector Operations</a>
3963</div>
3964
3965<div class="doc_text">
3966
3967<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968 target-independent manner. These instructions cover the element-access and
3969 vector-specific operations needed to process vectors effectively. While LLVM
3970 does directly support these vector operations, many sophisticated algorithms
3971 will want to use target-specific intrinsics to take full advantage of a
3972 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3973
3974</div>
3975
3976<!-- _______________________________________________________________________ -->
3977<div class="doc_subsubsection">
3978 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3979</div>
3980
3981<div class="doc_text">
3982
3983<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3984<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3985 &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]3986</pre>
3987
3988<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3990 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3991
3992
3993<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3994<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3995 of <a href="#t_vector">vector</a> type. The second operand is an index
3996 indicating the position from which to extract the element. The index may be
3997 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3998
3999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000<p>The result is a scalar of the same type as the element type of
4001 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4002 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4003 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4004
4005<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4006<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4007 &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]4008</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4011
4012<!-- _______________________________________________________________________ -->
4013<div class="doc_subsubsection">
4014 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4015</div>
4016
4017<div class="doc_text">
4018
4019<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4020<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4021 &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]4022</pre>
4023
4024<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4025<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4026 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4027
4028<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4029<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4030 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4031 whose type must equal the element type of the first operand. The third
4032 operand is an index indicating the position at which to insert the value.
4033 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4036<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4037 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4038 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4039 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4040
4041<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4042<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4043 &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]4044</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4046</div>
4047
4048<!-- _______________________________________________________________________ -->
4049<div class="doc_subsubsection">
4050 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4051</div>
4052
4053<div class="doc_text">
4054
4055<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4056<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4057 &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]4058</pre>
4059
4060<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4061<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4062 from two input vectors, returning a vector with the same element type as the
4063 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4067 with types that match each other. The third argument is a shuffle mask whose
4068 element type is always 'i32'. The result of the instruction is a vector
4069 whose length is the same as the shuffle mask and whose element type is the
4070 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4071
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4072<p>The shuffle mask operand is required to be a constant vector with either
4073 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4074
4075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076<p>The elements of the two input vectors are numbered from left to right across
4077 both of the vectors. The shuffle mask operand specifies, for each element of
4078 the result vector, which element of the two input vectors the result element
4079 gets. The element selector may be undef (meaning "don't care") and the
4080 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4081
4082<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4083<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4084 &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]4085 &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]4086 &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]4087 &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]4088 &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]4089 &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]4090 &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]4091 &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]4092</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4093
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4094</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4095
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4096<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4097<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4098 <a name="aggregateops">Aggregate Operations</a>
4099</div>
4100
4101<div class="doc_text">
4102
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4103<p>LLVM supports several instructions for working with
4104 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4105
4106</div>
4107
4108<!-- _______________________________________________________________________ -->
4109<div class="doc_subsubsection">
4110 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4111</div>
4112
4113<div class="doc_text">
4114
4115<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4116<pre>
4117 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4118</pre>
4119
4120<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4121<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4122 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4123
4124<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4125<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4126 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4127 <a href="#t_array">array</a> type. The operands are constant indices to
4128 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4130
4131<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4132<p>The result is the value at the position in the aggregate specified by the
4133 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4134
4135<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4136<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4137 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4138</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4139
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4140</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4141
4142<!-- _______________________________________________________________________ -->
4143<div class="doc_subsubsection">
4144 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4145</div>
4146
4147<div class="doc_text">
4148
4149<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4150<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4151 &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]4152</pre>
4153
4154<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4155<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4156 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4157
4158<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4160 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4161 <a href="#t_array">array</a> type. The second operand is a first-class
4162 value to insert. The following operands are constant indices indicating
4163 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]4164 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4165 value to insert must have the same type as the value identified by the
4166 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4167
4168<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4169<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4170 that of <tt>val</tt> except that the value at the position specified by the
4171 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4172
4173<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4174<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4175 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4176 %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]4177</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4179</div>
4180
4181
4182<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4183<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4184 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4185</div>
4186
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4187<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4188
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189<p>A key design point of an SSA-based representation is how it represents
4190 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4191 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4193
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4194</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4196<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4197<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4198 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4199</div>
4200
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4201<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4203<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4204<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4205 &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]4206</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4208<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4209<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210 currently executing function, to be automatically released when this function
4211 returns to its caller. The object is always allocated in the generic address
4212 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4213
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4214<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4215<p>The '<tt>alloca</tt>' instruction
4216 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4217 runtime stack, returning a pointer of the appropriate type to the program.
4218 If "NumElements" is specified, it is the number of elements allocated,
4219 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4220 specified, the value result of the allocation is guaranteed to be aligned to
4221 at least that boundary. If not specified, or if zero, the target can choose
4222 to align the allocation on any convenient boundary compatible with the
4223 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4225<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4227<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4228<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4229 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4230 memory is automatically released when the function returns. The
4231 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4232 variables that must have an address available. When the function returns
4233 (either with the <tt><a href="#i_ret">ret</a></tt>
4234 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4235 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4238<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4239 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4240 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4241 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4242 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4245</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4247<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4248<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4249Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4251<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4253<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4255 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4256 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4257 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4258</pre>
4259
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4260<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4261<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4262
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4263<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4264<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4265 from which to load. The pointer must point to
4266 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4267 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4268 number or order of execution of this <tt>load</tt> with other <a
4269 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4271<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4272 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]4273 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274 alignment for the target. It is the responsibility of the code emitter to
4275 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4276 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4277 produce less efficient code. An alignment of 1 is always safe.</p>
4278
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4279<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4280 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4281 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4282 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4283 and code generator that this load is not expected to be reused in the cache.
4284 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4285 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4286
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4287<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288<p>The location of memory pointed to is loaded. If the value being loaded is of
4289 scalar type then the number of bytes read does not exceed the minimum number
4290 of bytes needed to hold all bits of the type. For example, loading an
4291 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4292 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4293 is undefined if the value was not originally written using a store of the
4294 same type.</p>
4295
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4296<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297<pre>
4298 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4299 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4300 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4301</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4303</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4305<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4306<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4307Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4309<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4311<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4313 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>
4314 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]4315</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4318<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4320<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4321<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4322 and an address at which to store it. The type of the
4323 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4324 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4325 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4326 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4327 order of execution of this <tt>store</tt> with other <a
4328 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329
4330<p>The optional constant "align" argument specifies the alignment of the
4331 operation (that is, the alignment of the memory address). A value of 0 or an
4332 omitted "align" argument means that the operation has the preferential
4333 alignment for the target. It is the responsibility of the code emitter to
4334 ensure that the alignment information is correct. Overestimating the
4335 alignment results in an undefined behavior. Underestimating the alignment may
4336 produce less efficient code. An alignment of 1 is always safe.</p>
4337
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4338<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4339 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4340 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4341 instruction tells the optimizer and code generator that this load is
4342 not expected to be reused in the cache. The code generator may
4343 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4344 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4345
4346
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4347<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4349 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4350 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4351 does not exceed the minimum number of bytes needed to hold all bits of the
4352 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4353 writing a value of a type like <tt>i20</tt> with a size that is not an
4354 integral number of bytes, it is unspecified what happens to the extra bits
4355 that do not belong to the type, but they will typically be overwritten.</p>
4356
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4357<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358<pre>
4359 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4360 store i32 3, i32* %ptr <i>; yields {void}</i>
4361 %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]4362</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4363
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4364</div>
4365
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4366<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4367<div class="doc_subsubsection">
4368 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4369</div>
4370
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4371<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4372
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4373<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4374<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4375 &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]4376 &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]4377</pre>
4378
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4379<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4380<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4381 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4382 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4383
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4384<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4385<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4386 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4387 elements of the aggregate object are indexed. The interpretation of each
4388 index is dependent on the type being indexed into. The first index always
4389 indexes the pointer value given as the first argument, the second index
4390 indexes a value of the type pointed to (not necessarily the value directly
4391 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4392 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4393 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4394 can never be pointers, since that would require loading the pointer before
4395 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4396
4397<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4398 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4399 integer <b>constants</b> are allowed. When indexing into an array, pointer
4400 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]4401 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4402
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403<p>For example, let's consider a C code fragment and how it gets compiled to
4404 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4405
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4406<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4407struct RT {
4408 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4409 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4410 char C;
4411};
4412struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4413 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4414 double Y;
4415 struct RT Z;
4416};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4417
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4418int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4419 return &amp;s[1].Z.B[5][13];
4420}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4421</pre>
4422
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4423<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4424
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4425<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4426%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4427%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4428
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4429define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4430entry:
4431 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4432 ret i32* %reg
4433}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4434</pre>
4435
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4436<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4437<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]4438 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4439 }</tt>' type, a structure. The second index indexes into the third element
4440 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4441 i8 }</tt>' type, another structure. The third index indexes into the second
4442 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4443 array. The two dimensions of the array are subscripted into, yielding an
4444 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4445 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4447<p>Note that it is perfectly legal to index partially through a structure,
4448 returning a pointer to an inner element. Because of this, the LLVM code for
4449 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4450
4451<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4452 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4453 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4454 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4455 %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]4456 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4457 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4458 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4459 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4460</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4461
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4462<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4463 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4464 base pointer is not an <i>in bounds</i> address of an allocated object,
4465 or if any of the addresses that would be formed by successive addition of
4466 the offsets implied by the indices to the base address with infinitely
4467 precise arithmetic are not an <i>in bounds</i> address of that allocated
4468 object. The <i>in bounds</i> addresses for an allocated object are all
4469 the addresses that point into the object, plus the address one byte past
4470 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4471
4472<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4473 the base address with silently-wrapping two's complement arithmetic, and
4474 the result value of the <tt>getelementptr</tt> may be outside the object
4475 pointed to by the base pointer. The result value may not necessarily be
4476 used to access memory though, even if it happens to point into allocated
4477 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4478 section for more information.</p>
4479
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4480<p>The getelementptr instruction is often confusing. For some more insight into
4481 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4482
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4483<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4484<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4485 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4486 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4487 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4488 %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]4489 <i>; yields i8*:eptr</i>
4490 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4491 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4492 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4493</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4495</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4497<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4498<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4499</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4501<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4502
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4503<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4504 which all take a single operand and a type. They perform various bit
4505 conversions on the operand.</p>
4506
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4507</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4508
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4509<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4510<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4511 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4512</div>
4513<div class="doc_text">
4514
4515<h5>Syntax:</h5>
4516<pre>
4517 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4518</pre>
4519
4520<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4521<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4522 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4523
4524<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4526 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4527 size and type of the result, which must be
4528 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4529 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4530 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4531
4532<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4533<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4534 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4535 source size must be larger than the destination size, <tt>trunc</tt> cannot
4536 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4537
4538<h5>Example:</h5>
4539<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4540 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4541 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4542 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4543</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4545</div>
4546
4547<!-- _______________________________________________________________________ -->
4548<div class="doc_subsubsection">
4549 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4550</div>
4551<div class="doc_text">
4552
4553<h5>Syntax:</h5>
4554<pre>
4555 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4556</pre>
4557
4558<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4559<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4560 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4561
4562
4563<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4564<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]4565 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4566 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]4567 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4569
4570<h5>Semantics:</h5>
4571<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]4572 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4573
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4574<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]4575
4576<h5>Example:</h5>
4577<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4578 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4579 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4580</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4582</div>
4583
4584<!-- _______________________________________________________________________ -->
4585<div class="doc_subsubsection">
4586 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4587</div>
4588<div class="doc_text">
4589
4590<h5>Syntax:</h5>
4591<pre>
4592 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4593</pre>
4594
4595<h5>Overview:</h5>
4596<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4597
4598<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4599<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]4600 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4601 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]4602 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4603 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4604
4605<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4607 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4608 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4609
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4610<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]4611
4612<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4613<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4614 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4615 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4617
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4618</div>
4619
4620<!-- _______________________________________________________________________ -->
4621<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4622 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4623</div>
4624
4625<div class="doc_text">
4626
4627<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4628<pre>
4629 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4630</pre>
4631
4632<h5>Overview:</h5>
4633<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4634 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4635
4636<h5>Arguments:</h5>
4637<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4638 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4639 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]4640 <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]4641 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4642
4643<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4645 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4646 <a href="#t_floating">floating point</a> type. If the value cannot fit
4647 within the destination type, <tt>ty2</tt>, then the results are
4648 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4649
4650<h5>Example:</h5>
4651<pre>
4652 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4653 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4654</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4655
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4656</div>
4657
4658<!-- _______________________________________________________________________ -->
4659<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4660 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4661</div>
4662<div class="doc_text">
4663
4664<h5>Syntax:</h5>
4665<pre>
4666 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4667</pre>
4668
4669<h5>Overview:</h5>
4670<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]4671 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4672
4673<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4674<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4676 a <a href="#t_floating">floating point</a> type to cast it to. The source
4677 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4678
4679<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4680<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4681 <a href="#t_floating">floating point</a> type to a larger
4682 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4683 used to make a <i>no-op cast</i> because it always changes bits. Use
4684 <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]4685
4686<h5>Example:</h5>
4687<pre>
4688 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4689 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4692</div>
4693
4694<!-- _______________________________________________________________________ -->
4695<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4696 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4697</div>
4698<div class="doc_text">
4699
4700<h5>Syntax:</h5>
4701<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4702 &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]4703</pre>
4704
4705<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4706<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4708
4709<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4711 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4712 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4713 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4714 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4715
4716<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4717<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4718 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4719 towards zero) unsigned integer value. If the value cannot fit
4720 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4721
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4722<h5>Example:</h5>
4723<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4724 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4725 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4726 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4727</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4728
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4729</div>
4730
4731<!-- _______________________________________________________________________ -->
4732<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4733 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4734</div>
4735<div class="doc_text">
4736
4737<h5>Syntax:</h5>
4738<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4739 &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]4740</pre>
4741
4742<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4743<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744 <a href="#t_floating">floating point</a> <tt>value</tt> to
4745 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4746
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4747<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4749 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4750 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4751 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4752 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4753
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4754<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4755<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4756 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4757 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4758 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4759
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4760<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4761<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4762 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4763 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4764 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4765</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4766
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4767</div>
4768
4769<!-- _______________________________________________________________________ -->
4770<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4771 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4772</div>
4773<div class="doc_text">
4774
4775<h5>Syntax:</h5>
4776<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4777 &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]4778</pre>
4779
4780<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4781<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4782 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4783
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4784<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4785<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]4786 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4787 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4788 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4789 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4790
4791<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4792<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793 integer quantity and converts it to the corresponding floating point
4794 value. If the value cannot fit in the floating point value, the results are
4795 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4796
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4797<h5>Example:</h5>
4798<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4799 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4800 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4801</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4803</div>
4804
4805<!-- _______________________________________________________________________ -->
4806<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4807 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4808</div>
4809<div class="doc_text">
4810
4811<h5>Syntax:</h5>
4812<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4813 &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]4814</pre>
4815
4816<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4817<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4818 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4819
4820<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4821<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]4822 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4823 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4824 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4825 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4826
4827<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4828<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4829 quantity and converts it to the corresponding floating point value. If the
4830 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4831
4832<h5>Example:</h5>
4833<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4834 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4835 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4836</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4837
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4838</div>
4839
4840<!-- _______________________________________________________________________ -->
4841<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4842 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4843</div>
4844<div class="doc_text">
4845
4846<h5>Syntax:</h5>
4847<pre>
4848 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4849</pre>
4850
4851<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4852<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4853 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4854
4855<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4856<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4857 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4858 <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]4859
4860<h5>Semantics:</h5>
4861<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4863 truncating or zero extending that value to the size of the integer type. If
4864 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4865 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4866 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4867 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4868
4869<h5>Example:</h5>
4870<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4871 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4872 %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]4873</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4874
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4875</div>
4876
4877<!-- _______________________________________________________________________ -->
4878<div class="doc_subsubsection">
4879 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4880</div>
4881<div class="doc_text">
4882
4883<h5>Syntax:</h5>
4884<pre>
4885 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4886</pre>
4887
4888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4889<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4890 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4891
4892<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4893<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894 value to cast, and a type to cast it to, which must be a
4895 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4896
4897<h5>Semantics:</h5>
4898<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4900 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4901 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4902 than the size of a pointer then a zero extension is done. If they are the
4903 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4904
4905<h5>Example:</h5>
4906<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4907 %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]4908 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4909 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4911
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4912</div>
4913
4914<!-- _______________________________________________________________________ -->
4915<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4916 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4917</div>
4918<div class="doc_text">
4919
4920<h5>Syntax:</h5>
4921<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4922 &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]4923</pre>
4924
4925<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4926<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4928
4929<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4930<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4931 non-aggregate first class value, and a type to cast it to, which must also be
4932 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4933 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4934 identical. If the source type is a pointer, the destination type must also be
4935 a pointer. This instruction supports bitwise conversion of vectors to
4936 integers and to vectors of other types (as long as they have the same
4937 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4938
4939<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4940<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4941 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4942 this conversion. The conversion is done as if the <tt>value</tt> had been
4943 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4944 be converted to other pointer types with this instruction. To convert
4945 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4946 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4947
4948<h5>Example:</h5>
4949<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4950 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4951 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4952 %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]4953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4955</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4956
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4957<!-- ======================================================================= -->
4958<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4959
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4960<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4961
4962<p>The instructions in this category are the "miscellaneous" instructions, which
4963 defy better classification.</p>
4964
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4965</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4966
4967<!-- _______________________________________________________________________ -->
4968<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4969</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4970
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4971<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4972
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4973<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974<pre>
4975 &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]4976</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4977
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4978<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4980 boolean values based on comparison of its two integer, integer vector, or
4981 pointer operands.</p>
4982
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4983<h5>Arguments:</h5>
4984<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4985 the condition code indicating the kind of comparison to perform. It is not a
4986 value, just a keyword. The possible condition code are:</p>
4987
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4988<ol>
4989 <li><tt>eq</tt>: equal</li>
4990 <li><tt>ne</tt>: not equal </li>
4991 <li><tt>ugt</tt>: unsigned greater than</li>
4992 <li><tt>uge</tt>: unsigned greater or equal</li>
4993 <li><tt>ult</tt>: unsigned less than</li>
4994 <li><tt>ule</tt>: unsigned less or equal</li>
4995 <li><tt>sgt</tt>: signed greater than</li>
4996 <li><tt>sge</tt>: signed greater or equal</li>
4997 <li><tt>slt</tt>: signed less than</li>
4998 <li><tt>sle</tt>: signed less or equal</li>
4999</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5000
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5001<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5002 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5003 typed. They must also be identical types.</p>
5004
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5005<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5007 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5008 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]5009 result, as follows:</p>
5010
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5011<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5012 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013 <tt>false</tt> otherwise. No sign interpretation is necessary or
5014 performed.</li>
5015
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5016 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5017 <tt>false</tt> otherwise. No sign interpretation is necessary or
5018 performed.</li>
5019
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5020 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5022
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5023 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5024 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5025 to <tt>op2</tt>.</li>
5026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5027 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5030 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5031 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5032
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5033 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5036 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5038 to <tt>op2</tt>.</li>
5039
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5042
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5043 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044 <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]5045</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5046
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5047<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048 values are compared as if they were integers.</p>
5049
5050<p>If the operands are integer vectors, then they are compared element by
5051 element. The result is an <tt>i1</tt> vector with the same number of elements
5052 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5053
5054<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5055<pre>
5056 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5057 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5058 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5059 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5060 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5061 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5062</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5063
5064<p>Note that the code generator does not yet support vector types with
5065 the <tt>icmp</tt> instruction.</p>
5066
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5067</div>
5068
5069<!-- _______________________________________________________________________ -->
5070<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5071</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5072
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5073<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5074
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5075<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076<pre>
5077 &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]5078</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5079
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5080<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5081<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5082 values based on comparison of its operands.</p>
5083
5084<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]5085(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5086
5087<p>If the operands are floating point vectors, then the result type is a vector
5088 of boolean with the same number of elements as the operands being
5089 compared.</p>
5090
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5091<h5>Arguments:</h5>
5092<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5093 the condition code indicating the kind of comparison to perform. It is not a
5094 value, just a keyword. The possible condition code are:</p>
5095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5097 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5098 <li><tt>oeq</tt>: ordered and equal</li>
5099 <li><tt>ogt</tt>: ordered and greater than </li>
5100 <li><tt>oge</tt>: ordered and greater than or equal</li>
5101 <li><tt>olt</tt>: ordered and less than </li>
5102 <li><tt>ole</tt>: ordered and less than or equal</li>
5103 <li><tt>one</tt>: ordered and not equal</li>
5104 <li><tt>ord</tt>: ordered (no nans)</li>
5105 <li><tt>ueq</tt>: unordered or equal</li>
5106 <li><tt>ugt</tt>: unordered or greater than </li>
5107 <li><tt>uge</tt>: unordered or greater than or equal</li>
5108 <li><tt>ult</tt>: unordered or less than </li>
5109 <li><tt>ule</tt>: unordered or less than or equal</li>
5110 <li><tt>une</tt>: unordered or not equal</li>
5111 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5112 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5113</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5114
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5115<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116 <i>unordered</i> means that either operand may be a QNAN.</p>
5117
5118<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5119 a <a href="#t_floating">floating point</a> type or
5120 a <a href="#t_vector">vector</a> of floating point type. They must have
5121 identical types.</p>
5122
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5123<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5124<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5125 according to the condition code given as <tt>cond</tt>. If the operands are
5126 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5127 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5128 follows:</p>
5129
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5130<ol>
5131 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5132
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5133 <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]5134 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5135
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5136 <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]5137 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5138
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5139 <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]5140 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5141
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5142 <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]5143 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5144
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5145 <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]5146 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5147
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5148 <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]5149 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5150
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5151 <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]5152
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5153 <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]5154 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5155
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5156 <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]5157 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5162 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5164
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5165 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5166 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5167
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5168 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5169 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5170
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5171 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5172
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5173 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5174</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5175
5176<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5177<pre>
5178 &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]5179 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5180 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5181 &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]5182</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5183
5184<p>Note that the code generator does not yet support vector types with
5185 the <tt>fcmp</tt> instruction.</p>
5186
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5187</div>
5188
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5189<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5190<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5191 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5192</div>
5193
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5194<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5195
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5196<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5197<pre>
5198 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5199</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5200
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5201<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5203 SSA graph representing the function.</p>
5204
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5205<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5206<p>The type of the incoming values is specified with the first type field. After
5207 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5208 one pair for each predecessor basic block of the current block. Only values
5209 of <a href="#t_firstclass">first class</a> type may be used as the value
5210 arguments to the PHI node. Only labels may be used as the label
5211 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5212
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5213<p>There must be no non-phi instructions between the start of a basic block and
5214 the PHI instructions: i.e. PHI instructions must be first in a basic
5215 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5216
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5218 occur on the edge from the corresponding predecessor block to the current
5219 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5220 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5221
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5222<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5223<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5224 specified by the pair corresponding to the predecessor basic block that
5225 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5226
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5227<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5228<pre>
5229Loop: ; Infinite loop that counts from 0 on up...
5230 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5231 %nextindvar = add i32 %indvar, 1
5232 br label %Loop
5233</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5234
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5235</div>
5236
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5237<!-- _______________________________________________________________________ -->
5238<div class="doc_subsubsection">
5239 <a name="i_select">'<tt>select</tt>' Instruction</a>
5240</div>
5241
5242<div class="doc_text">
5243
5244<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5245<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5246 &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>
5247
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5248 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5249</pre>
5250
5251<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5252<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5253 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5254
5255
5256<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5257<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5258 values indicating the condition, and two values of the
5259 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5260 vectors and the condition is a scalar, then entire vectors are selected, not
5261 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5262
5263<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5264<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5265 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5266
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5267<p>If the condition is a vector of i1, then the value arguments must be vectors
5268 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5269
5270<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5271<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5272 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5273</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5274
5275<p>Note that the code generator does not yet support conditions
5276 with vector type.</p>
5277
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5278</div>
5279
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5280<!-- _______________________________________________________________________ -->
5281<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5282 <a name="i_call">'<tt>call</tt>' Instruction</a>
5283</div>
5284
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5285<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5286
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5287<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5288<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5289 &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]5290</pre>
5291
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5292<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5293<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5295<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5296<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5297
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5298<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5299 <li>The optional "tail" marker indicates that the callee function does not
5300 access any allocas or varargs in the caller. Note that calls may be
5301 marked "tail" even if they do not occur before
5302 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5303 present, the function call is eligible for tail call optimization,
5304 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5305 optimized into a jump</a>. The code generator may optimize calls marked
5306 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5307 sibling call optimization</a> when the caller and callee have
5308 matching signatures, or 2) forced tail call optimization when the
5309 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5310 <ul>
5311 <li>Caller and callee both have the calling
5312 convention <tt>fastcc</tt>.</li>
5313 <li>The call is in tail position (ret immediately follows call and ret
5314 uses value of call or is void).</li>
5315 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5316 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5317 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5318 constraints are met.</a></li>
5319 </ul>
5320 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5321
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5322 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5323 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5324 defaults to using C calling conventions. The calling convention of the
5325 call must match the calling convention of the target function, or else the
5326 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5327
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5329 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5330 '<tt>inreg</tt>' attributes are valid here.</li>
5331
5332 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5333 type of the return value. Functions that return no value are marked
5334 <tt><a href="#t_void">void</a></tt>.</li>
5335
5336 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5337 being invoked. The argument types must match the types implied by this
5338 signature. This type can be omitted if the function is not varargs and if
5339 the function type does not return a pointer to a function.</li>
5340
5341 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5342 be invoked. In most cases, this is a direct function invocation, but
5343 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5344 to function value.</li>
5345
5346 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5347 signature argument types and parameter attributes. All arguments must be
5348 of <a href="#t_firstclass">first class</a> type. If the function
5349 signature indicates the function accepts a variable number of arguments,
5350 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5351
5352 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5353 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5354 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5355</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5356
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5357<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5358<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5359 a specified function, with its incoming arguments bound to the specified
5360 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5361 function, control flow continues with the instruction after the function
5362 call, and the return value of the function is bound to the result
5363 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5364
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5365<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5366<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5367 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5368 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5369 %X = tail call i32 @foo() <i>; yields i32</i>
5370 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5371 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5372
5373 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5374 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5375 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5376 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5377 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5378 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5379</pre>
5380
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5381<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5382standard C99 library as being the C99 library functions, and may perform
5383optimizations or generate code for them under that assumption. This is
5384something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5385freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5386
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5387</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5388
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5389<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5390<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5391 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5392</div>
5393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5394<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5395
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5396<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5397<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5398 &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]5399</pre>
5400
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5401<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5402<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5403 the "variable argument" area of a function call. It is used to implement the
5404 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5405
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5406<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5407<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5408 argument. It returns a value of the specified argument type and increments
5409 the <tt>va_list</tt> to point to the next argument. The actual type
5410 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5411
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5412<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5414 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5415 to the next argument. For more information, see the variable argument
5416 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5417
5418<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]5419 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5420 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5421
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5422<p><tt>va_arg</tt> is an LLVM instruction instead of
5423 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5424 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5425
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5427<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5428
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5429<p>Note that the code generator does not yet fully support va_arg on many
5430 targets. Also, it does not currently support va_arg with aggregate types on
5431 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5432
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5433</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5434
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5435<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5436<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5437<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5438
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5439<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5440
5441<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442 well known names and semantics and are required to follow certain
5443 restrictions. Overall, these intrinsics represent an extension mechanism for
5444 the LLVM language that does not require changing all of the transformations
5445 in LLVM when adding to the language (or the bitcode reader/writer, the
5446 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5447
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5448<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5449 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5450 begin with this prefix. Intrinsic functions must always be external
5451 functions: you cannot define the body of intrinsic functions. Intrinsic
5452 functions may only be used in call or invoke instructions: it is illegal to
5453 take the address of an intrinsic function. Additionally, because intrinsic
5454 functions are part of the LLVM language, it is required if any are added that
5455 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5457<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5458 family of functions that perform the same operation but on different data
5459 types. Because LLVM can represent over 8 million different integer types,
5460 overloading is used commonly to allow an intrinsic function to operate on any
5461 integer type. One or more of the argument types or the result type can be
5462 overloaded to accept any integer type. Argument types may also be defined as
5463 exactly matching a previous argument's type or the result type. This allows
5464 an intrinsic function which accepts multiple arguments, but needs all of them
5465 to be of the same type, to only be overloaded with respect to a single
5466 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5467
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468<p>Overloaded intrinsics will have the names of its overloaded argument types
5469 encoded into its function name, each preceded by a period. Only those types
5470 which are overloaded result in a name suffix. Arguments whose type is matched
5471 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5472 can take an integer of any width and returns an integer of exactly the same
5473 integer width. This leads to a family of functions such as
5474 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5475 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5476 suffix is required. Because the argument's type is matched against the return
5477 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5478
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5479<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5482</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5483
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5484<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5485<div class="doc_subsection">
5486 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5487</div>
5488
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5489<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5490
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5491<p>Variable argument support is defined in LLVM with
5492 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5493 intrinsic functions. These functions are related to the similarly named
5494 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5495
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5496<p>All of these functions operate on arguments that use a target-specific value
5497 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5498 not define what this type is, so all transformations should be prepared to
5499 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5500
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5501<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]5502 instruction and the variable argument handling intrinsic functions are
5503 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5504
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5505<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5506define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5507 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5508 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5509 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5510 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5511
5512 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5513 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5514
5515 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5516 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5517 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5518 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5519 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5520
5521 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5522 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5523 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5524}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5525
5526declare void @llvm.va_start(i8*)
5527declare void @llvm.va_copy(i8*, i8*)
5528declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5529</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5530
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5531</div>
5532
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5533<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5534<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5535 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5536</div>
5537
5538
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5539<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5540
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5541<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5542<pre>
5543 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5544</pre>
5545
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5546<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5547<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5548 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]5549
5550<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5551<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]5552
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5553<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5554<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]5555 macro available in C. In a target-dependent way, it initializes
5556 the <tt>va_list</tt> element to which the argument points, so that the next
5557 call to <tt>va_arg</tt> will produce the first variable argument passed to
5558 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5559 need to know the last argument of the function as the compiler can figure
5560 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5561
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5562</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5563
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5564<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5565<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5566 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5567</div>
5568
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5569<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5570
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5571<h5>Syntax:</h5>
5572<pre>
5573 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5574</pre>
5575
5576<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5577<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5578 which has been initialized previously
5579 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5580 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5581
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5582<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5583<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]5584
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5585<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5586<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]5587 macro available in C. In a target-dependent way, it destroys
5588 the <tt>va_list</tt> element to which the argument points. Calls
5589 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5590 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5591 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5593</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5594
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5595<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5596<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5597 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5598</div>
5599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5600<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5601
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5602<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5603<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5604 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5605</pre>
5606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5608<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5609 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5610
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5611<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5612<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]5613 The second argument is a pointer to a <tt>va_list</tt> element to copy
5614 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5615
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5616<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5617<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]5618 macro available in C. In a target-dependent way, it copies the
5619 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5620 element. This intrinsic is necessary because
5621 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5622 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5624</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5625
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5626<!-- ======================================================================= -->
5627<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5628 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5629</div>
5630
5631<div class="doc_text">
5632
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5633<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5634Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5635intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5636roots on the stack</a>, as well as garbage collector implementations that
5637require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5638barriers. Front-ends for type-safe garbage collected languages should generate
5639these intrinsics to make use of the LLVM garbage collectors. For more details,
5640see <a href="GarbageCollection.html">Accurate Garbage Collection with
5641LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5643<p>The garbage collection intrinsics only operate on objects in the generic
5644 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5645
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5646</div>
5647
5648<!-- _______________________________________________________________________ -->
5649<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5650 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5651</div>
5652
5653<div class="doc_text">
5654
5655<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5656<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5657 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5658</pre>
5659
5660<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5661<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]5662 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5663
5664<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5665<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5666 root pointer. The second pointer (which must be either a constant or a
5667 global value address) contains the meta-data to be associated with the
5668 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5669
5670<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5671<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]5672 location. At compile-time, the code generator generates information to allow
5673 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5674 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5675 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676
5677</div>
5678
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5679<!-- _______________________________________________________________________ -->
5680<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5681 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5682</div>
5683
5684<div class="doc_text">
5685
5686<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5687<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5688 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689</pre>
5690
5691<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5692<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693 locations, allowing garbage collector implementations that require read
5694 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5695
5696<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5697<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]5698 allocated from the garbage collector. The first object is a pointer to the
5699 start of the referenced object, if needed by the language runtime (otherwise
5700 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701
5702<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5703<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5704 instruction, but may be replaced with substantially more complex code by the
5705 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5706 may only be used in a function which <a href="#gc">specifies a GC
5707 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5708
5709</div>
5710
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5711<!-- _______________________________________________________________________ -->
5712<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5713 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5714</div>
5715
5716<div class="doc_text">
5717
5718<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5719<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5720 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5721</pre>
5722
5723<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5724<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5725 locations, allowing garbage collector implementations that require write
5726 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5727
5728<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5729<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]5730 object to store it to, and the third is the address of the field of Obj to
5731 store to. If the runtime does not require a pointer to the object, Obj may
5732 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5733
5734<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5735<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5736 instruction, but may be replaced with substantially more complex code by the
5737 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5738 may only be used in a function which <a href="#gc">specifies a GC
5739 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5740
5741</div>
5742
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5743<!-- ======================================================================= -->
5744<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5745 <a name="int_codegen">Code Generator Intrinsics</a>
5746</div>
5747
5748<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5749
5750<p>These intrinsics are provided by LLVM to expose special features that may
5751 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5752
5753</div>
5754
5755<!-- _______________________________________________________________________ -->
5756<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5757 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5758</div>
5759
5760<div class="doc_text">
5761
5762<h5>Syntax:</h5>
5763<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5764 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5765</pre>
5766
5767<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5768<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5769 target-specific value indicating the return address of the current function
5770 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5771
5772<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5773<p>The argument to this intrinsic indicates which function to return the address
5774 for. Zero indicates the calling function, one indicates its caller, etc.
5775 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5776
5777<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5778<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5779 indicating the return address of the specified call frame, or zero if it
5780 cannot be identified. The value returned by this intrinsic is likely to be
5781 incorrect or 0 for arguments other than zero, so it should only be used for
5782 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5783
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5784<p>Note that calling this intrinsic does not prevent function inlining or other
5785 aggressive transformations, so the value returned may not be that of the
5786 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788</div>
5789
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5790<!-- _______________________________________________________________________ -->
5791<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5792 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5793</div>
5794
5795<div class="doc_text">
5796
5797<h5>Syntax:</h5>
5798<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5799 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5800</pre>
5801
5802<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5804 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5805
5806<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The argument to this intrinsic indicates which function to return the frame
5808 pointer for. Zero indicates the calling function, one indicates its caller,
5809 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5810
5811<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5813 indicating the frame address of the specified call frame, or zero if it
5814 cannot be identified. The value returned by this intrinsic is likely to be
5815 incorrect or 0 for arguments other than zero, so it should only be used for
5816 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5817
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5818<p>Note that calling this intrinsic does not prevent function inlining or other
5819 aggressive transformations, so the value returned may not be that of the
5820 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5821
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5822</div>
5823
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5824<!-- _______________________________________________________________________ -->
5825<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5826 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5827</div>
5828
5829<div class="doc_text">
5830
5831<h5>Syntax:</h5>
5832<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5833 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5834</pre>
5835
5836<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5837<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5838 of the function stack, for use
5839 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5840 useful for implementing language features like scoped automatic variable
5841 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5842
5843<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844<p>This intrinsic returns a opaque pointer value that can be passed
5845 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5846 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5847 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5848 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5849 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5850 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5851
5852</div>
5853
5854<!-- _______________________________________________________________________ -->
5855<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5856 <a name="int_stackrestore">'<tt>llvm.stackrestore</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 void @llvm.stackrestore(i8* %ptr)
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.stackrestore</tt>' intrinsic is used to restore the state of
5868 the function stack to the state it was in when the
5869 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5870 executed. This is useful for implementing language features like scoped
5871 automatic variable 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>See the description
5875 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5876
5877</div>
5878
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5879<!-- _______________________________________________________________________ -->
5880<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5881 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5882</div>
5883
5884<div class="doc_text">
5885
5886<h5>Syntax:</h5>
5887<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5888 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]5889</pre>
5890
5891<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5892<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5893 insert a prefetch instruction if supported; otherwise, it is a noop.
5894 Prefetches have no effect on the behavior of the program but can change its
5895 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5896
5897<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5898<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5899 specifier determining if the fetch should be for a read (0) or write (1),
5900 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5901 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5902 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5903
5904<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5905<p>This intrinsic does not modify the behavior of the program. In particular,
5906 prefetches cannot trap and do not produce a value. On targets that support
5907 this intrinsic, the prefetch can provide hints to the processor cache for
5908 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5909
5910</div>
5911
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5912<!-- _______________________________________________________________________ -->
5913<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5914 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5915</div>
5916
5917<div class="doc_text">
5918
5919<h5>Syntax:</h5>
5920<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5921 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5922</pre>
5923
5924<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5925<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5926 Counter (PC) in a region of code to simulators and other tools. The method
5927 is target specific, but it is expected that the marker will use exported
5928 symbols to transmit the PC of the marker. The marker makes no guarantees
5929 that it will remain with any specific instruction after optimizations. It is
5930 possible that the presence of a marker will inhibit optimizations. The
5931 intended use is to be inserted after optimizations to allow correlations of
5932 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5933
5934<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5936
5937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5938<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5939 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5940
5941</div>
5942
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5943<!-- _______________________________________________________________________ -->
5944<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5945 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5946</div>
5947
5948<div class="doc_text">
5949
5950<h5>Syntax:</h5>
5951<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5952 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5953</pre>
5954
5955<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5957 counter register (or similar low latency, high accuracy clocks) on those
5958 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5959 should map to RPCC. As the backing counters overflow quickly (on the order
5960 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5961
5962<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5963<p>When directly supported, reading the cycle counter should not modify any
5964 memory. Implementations are allowed to either return a application specific
5965 value or a system wide value. On backends without support, this is lowered
5966 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5967
5968</div>
5969
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5970<!-- ======================================================================= -->
5971<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5972 <a name="int_libc">Standard C Library Intrinsics</a>
5973</div>
5974
5975<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976
5977<p>LLVM provides intrinsics for a few important standard C library functions.
5978 These intrinsics allow source-language front-ends to pass information about
5979 the alignment of the pointer arguments to the code generator, providing
5980 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5981
5982</div>
5983
5984<!-- _______________________________________________________________________ -->
5985<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5986 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5987</div>
5988
5989<div class="doc_text">
5990
5991<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992<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]5993 integer bit width and for different address spaces. Not all targets support
5994 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5995
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5996<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5997 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]5998 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5999 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]6000 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6001</pre>
6002
6003<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6005 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6008 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6009 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6010
6011<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6012
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6013<p>The first argument is a pointer to the destination, the second is a pointer
6014 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6015 number of bytes to copy, the fourth argument is the alignment of the
6016 source and destination locations, and the fifth is a boolean indicating a
6017 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6018
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6019<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]6020 then the caller guarantees that both the source and destination pointers are
6021 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6022
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6023<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6024 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6025 The detailed access behavior is not very cleanly specified and it is unwise
6026 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6027
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6028<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6030<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6031 source location to the destination location, which are not allowed to
6032 overlap. It copies "len" bytes of memory over. If the argument is known to
6033 be aligned to some boundary, this can be specified as the fourth argument,
6034 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6035
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6036</div>
6037
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6038<!-- _______________________________________________________________________ -->
6039<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6040 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6041</div>
6042
6043<div class="doc_text">
6044
6045<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6046<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]6047 width and for different address space. Not all targets support all bit
6048 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6050<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6051 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]6052 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6053 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]6054 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6055</pre>
6056
6057<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6059 source location to the destination location. It is similar to the
6060 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6061 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6063<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6064 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6065 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6066
6067<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6068
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6069<p>The first argument is a pointer to the destination, the second is a pointer
6070 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6071 number of bytes to copy, the fourth argument is the alignment of the
6072 source and destination locations, and the fifth is a boolean indicating a
6073 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6074
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6075<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]6076 then the caller guarantees that the source and destination pointers are
6077 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6078
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6079<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6080 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6081 The detailed access behavior is not very cleanly specified and it is unwise
6082 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6083
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6084<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6085
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6087 source location to the destination location, which may overlap. It copies
6088 "len" bytes of memory over. If the argument is known to be aligned to some
6089 boundary, this can be specified as the fourth argument, otherwise it should
6090 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6091
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6092</div>
6093
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6094<!-- _______________________________________________________________________ -->
6095<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6096 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6097</div>
6098
6099<div class="doc_text">
6100
6101<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6102<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]6103 width and for different address spaces. However, not all targets support all
6104 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6105
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6106<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6107 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6108 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6109 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6110 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6111</pre>
6112
6113<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6114<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6115 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6117<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6118 intrinsic does not return a value and takes extra alignment/volatile
6119 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6120
6121<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122<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]6123 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6124 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6125 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6126
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6127<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]6128 then the caller guarantees that the destination pointer is aligned to that
6129 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6130
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6131<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6132 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6133 The detailed access behavior is not very cleanly specified and it is unwise
6134 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6135
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6136<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6138 at the destination location. If the argument is known to be aligned to some
6139 boundary, this can be specified as the fourth argument, otherwise it should
6140 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6141
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6142</div>
6143
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6144<!-- _______________________________________________________________________ -->
6145<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6146 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6147</div>
6148
6149<div class="doc_text">
6150
6151<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6153 floating point or vector of floating point type. Not all targets support all
6154 types however.</p>
6155
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6156<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6157 declare float @llvm.sqrt.f32(float %Val)
6158 declare double @llvm.sqrt.f64(double %Val)
6159 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6160 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6161 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6162</pre>
6163
6164<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6165<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6166 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6167 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6168 behavior for negative numbers other than -0.0 (which allows for better
6169 optimization, because there is no need to worry about errno being
6170 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]6171
6172<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The argument and return value are floating point numbers of the same
6174 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6175
6176<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6177<p>This function returns the sqrt of the specified operand if it is a
6178 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6179
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6180</div>
6181
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6182<!-- _______________________________________________________________________ -->
6183<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6184 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6185</div>
6186
6187<div class="doc_text">
6188
6189<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6190<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6191 floating point or vector of floating point type. Not all targets support all
6192 types however.</p>
6193
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6194<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6195 declare float @llvm.powi.f32(float %Val, i32 %power)
6196 declare double @llvm.powi.f64(double %Val, i32 %power)
6197 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6198 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6199 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6200</pre>
6201
6202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6204 specified (positive or negative) power. The order of evaluation of
6205 multiplications is not defined. When a vector of floating point type is
6206 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6207
6208<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209<p>The second argument is an integer power, and the first is a value to raise to
6210 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6211
6212<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6213<p>This function returns the first value raised to the second power with an
6214 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6215
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6216</div>
6217
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
6220 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6226<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6227 floating point or vector of floating point type. Not all targets support all
6228 types however.</p>
6229
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6230<pre>
6231 declare float @llvm.sin.f32(float %Val)
6232 declare double @llvm.sin.f64(double %Val)
6233 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6234 declare fp128 @llvm.sin.f128(fp128 %Val)
6235 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6236</pre>
6237
6238<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6240
6241<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6242<p>The argument and return value are floating point numbers of the same
6243 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6244
6245<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6246<p>This function returns the sine of the specified operand, returning the same
6247 values as the libm <tt>sin</tt> functions would, and handles error conditions
6248 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6249
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6250</div>
6251
6252<!-- _______________________________________________________________________ -->
6253<div class="doc_subsubsection">
6254 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6255</div>
6256
6257<div class="doc_text">
6258
6259<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6260<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6261 floating point or vector of floating point type. Not all targets support all
6262 types however.</p>
6263
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6264<pre>
6265 declare float @llvm.cos.f32(float %Val)
6266 declare double @llvm.cos.f64(double %Val)
6267 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6268 declare fp128 @llvm.cos.f128(fp128 %Val)
6269 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6270</pre>
6271
6272<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6273<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6274
6275<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276<p>The argument and return value are floating point numbers of the same
6277 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6278
6279<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6280<p>This function returns the cosine of the specified operand, returning the same
6281 values as the libm <tt>cos</tt> functions would, and handles error conditions
6282 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6283
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6284</div>
6285
6286<!-- _______________________________________________________________________ -->
6287<div class="doc_subsubsection">
6288 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6289</div>
6290
6291<div class="doc_text">
6292
6293<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6294<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6295 floating point or vector of floating point type. Not all targets support all
6296 types however.</p>
6297
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6298<pre>
6299 declare float @llvm.pow.f32(float %Val, float %Power)
6300 declare double @llvm.pow.f64(double %Val, double %Power)
6301 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6302 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6303 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6304</pre>
6305
6306<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6307<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6308 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6309
6310<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6311<p>The second argument is a floating point power, and the first is a value to
6312 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6313
6314<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315<p>This function returns the first value raised to the second power, returning
6316 the same values as the libm <tt>pow</tt> functions would, and handles error
6317 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6318
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6319</div>
6320
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6321<!-- ======================================================================= -->
6322<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6323 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6324</div>
6325
6326<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6327
6328<p>LLVM provides intrinsics for a few important bit manipulation operations.
6329 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6330
6331</div>
6332
6333<!-- _______________________________________________________________________ -->
6334<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6335 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6336</div>
6337
6338<div class="doc_text">
6339
6340<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6341<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6342 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6343
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6344<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6345 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6346 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6347 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6348</pre>
6349
6350<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6351<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6352 values with an even number of bytes (positive multiple of 16 bits). These
6353 are useful for performing operations on data that is not in the target's
6354 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6355
6356<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6357<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6358 and low byte of the input i16 swapped. Similarly,
6359 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6360 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6361 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6362 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6363 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6364 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6365
6366</div>
6367
6368<!-- _______________________________________________________________________ -->
6369<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6370 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6371</div>
6372
6373<div class="doc_text">
6374
6375<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6376<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]6377 width. Not all targets support all bit widths however.</p>
6378
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6379<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6380 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6381 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6382 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6383 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6384 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6385</pre>
6386
6387<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6388<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6389 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6390
6391<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6392<p>The only argument is the value to be counted. The argument may be of any
6393 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6394
6395<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396<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]6397
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6398</div>
6399
6400<!-- _______________________________________________________________________ -->
6401<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6402 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6403</div>
6404
6405<div class="doc_text">
6406
6407<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6409 integer bit width. Not all targets support all bit widths however.</p>
6410
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6411<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6412 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6413 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6414 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6415 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6416 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6417</pre>
6418
6419<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6420<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6421 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6422
6423<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p>The only argument is the value to be counted. The argument may be of any
6425 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6426
6427<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6429 zeros in a variable. If the src == 0 then the result is the size in bits of
6430 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6431
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6432</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6433
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6434<!-- _______________________________________________________________________ -->
6435<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6436 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6437</div>
6438
6439<div class="doc_text">
6440
6441<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6442<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6443 integer bit width. Not all targets support all bit widths however.</p>
6444
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6445<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6446 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6447 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6448 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6449 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6450 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6455 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6456
6457<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458<p>The only argument is the value to be counted. The argument may be of any
6459 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6460
6461<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6463 zeros in a variable. If the src == 0 then the result is the size in bits of
6464 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6465
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6466</div>
6467
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6468<!-- ======================================================================= -->
6469<div class="doc_subsection">
6470 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6471</div>
6472
6473<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6474
6475<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6476
6477</div>
6478
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6479<!-- _______________________________________________________________________ -->
6480<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6481 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6482</div>
6483
6484<div class="doc_text">
6485
6486<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6487<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]6488 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6489
6490<pre>
6491 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6492 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6493 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6494</pre>
6495
6496<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6497<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498 a signed addition of the two arguments, and indicate whether an overflow
6499 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6500
6501<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6502<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]6503 be of integer types of any bit width, but they must have the same bit
6504 width. The second element of the result structure must be of
6505 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6506 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6507
6508<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6509<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510 a signed addition of the two variables. They return a structure &mdash; the
6511 first element of which is the signed summation, and the second element of
6512 which is a bit specifying if the signed summation resulted in an
6513 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6514
6515<h5>Examples:</h5>
6516<pre>
6517 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6518 %sum = extractvalue {i32, i1} %res, 0
6519 %obit = extractvalue {i32, i1} %res, 1
6520 br i1 %obit, label %overflow, label %normal
6521</pre>
6522
6523</div>
6524
6525<!-- _______________________________________________________________________ -->
6526<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6527 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6528</div>
6529
6530<div class="doc_text">
6531
6532<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6533<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]6534 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6535
6536<pre>
6537 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6538 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6539 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6540</pre>
6541
6542<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6543<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544 an unsigned addition of the two arguments, and indicate whether a carry
6545 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6546
6547<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6548<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]6549 be of integer types of any bit width, but they must have the same bit
6550 width. The second element of the result structure must be of
6551 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6552 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553
6554<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6555<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6556 an unsigned addition of the two arguments. They return a structure &mdash;
6557 the first element of which is the sum, and the second element of which is a
6558 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6559
6560<h5>Examples:</h5>
6561<pre>
6562 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6563 %sum = extractvalue {i32, i1} %res, 0
6564 %obit = extractvalue {i32, i1} %res, 1
6565 br i1 %obit, label %carry, label %normal
6566</pre>
6567
6568</div>
6569
6570<!-- _______________________________________________________________________ -->
6571<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6572 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573</div>
6574
6575<div class="doc_text">
6576
6577<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6578<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]6579 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6580
6581<pre>
6582 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6583 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6584 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6585</pre>
6586
6587<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6588<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6589 a signed subtraction of the two arguments, and indicate whether an overflow
6590 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6591
6592<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6593<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]6594 be of integer types of any bit width, but they must have the same bit
6595 width. The second element of the result structure must be of
6596 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6597 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6598
6599<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6600<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6601 a signed subtraction of the two arguments. They return a structure &mdash;
6602 the first element of which is the subtraction, and the second element of
6603 which is a bit specifying if the signed subtraction resulted in an
6604 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6605
6606<h5>Examples:</h5>
6607<pre>
6608 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6609 %sum = extractvalue {i32, i1} %res, 0
6610 %obit = extractvalue {i32, i1} %res, 1
6611 br i1 %obit, label %overflow, label %normal
6612</pre>
6613
6614</div>
6615
6616<!-- _______________________________________________________________________ -->
6617<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6618 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6619</div>
6620
6621<div class="doc_text">
6622
6623<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6624<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]6625 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6626
6627<pre>
6628 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6629 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6630 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6631</pre>
6632
6633<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6634<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6635 an unsigned subtraction of the two arguments, and indicate whether an
6636 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6637
6638<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6639<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]6640 be of integer types of any bit width, but they must have the same bit
6641 width. The second element of the result structure must be of
6642 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6643 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6644
6645<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6646<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6647 an unsigned subtraction of the two arguments. They return a structure &mdash;
6648 the first element of which is the subtraction, and the second element of
6649 which is a bit specifying if the unsigned subtraction resulted in an
6650 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6651
6652<h5>Examples:</h5>
6653<pre>
6654 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6655 %sum = extractvalue {i32, i1} %res, 0
6656 %obit = extractvalue {i32, i1} %res, 1
6657 br i1 %obit, label %overflow, label %normal
6658</pre>
6659
6660</div>
6661
6662<!-- _______________________________________________________________________ -->
6663<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6664 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6665</div>
6666
6667<div class="doc_text">
6668
6669<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6670<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]6671 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6672
6673<pre>
6674 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6675 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6676 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6677</pre>
6678
6679<h5>Overview:</h5>
6680
6681<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6682 a signed multiplication of the two arguments, and indicate whether an
6683 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6684
6685<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6686<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]6687 be of integer types of any bit width, but they must have the same bit
6688 width. The second element of the result structure must be of
6689 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6690 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6691
6692<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6693<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6694 a signed multiplication of the two arguments. They return a structure &mdash;
6695 the first element of which is the multiplication, and the second element of
6696 which is a bit specifying if the signed multiplication resulted in an
6697 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6698
6699<h5>Examples:</h5>
6700<pre>
6701 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6702 %sum = extractvalue {i32, i1} %res, 0
6703 %obit = extractvalue {i32, i1} %res, 1
6704 br i1 %obit, label %overflow, label %normal
6705</pre>
6706
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6707</div>
6708
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6709<!-- _______________________________________________________________________ -->
6710<div class="doc_subsubsection">
6711 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6712</div>
6713
6714<div class="doc_text">
6715
6716<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6717<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]6718 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6719
6720<pre>
6721 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6722 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6723 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6724</pre>
6725
6726<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6727<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6728 a unsigned multiplication of the two arguments, and indicate whether an
6729 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6730
6731<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6732<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]6733 be of integer types of any bit width, but they must have the same bit
6734 width. The second element of the result structure must be of
6735 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6736 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6737
6738<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6739<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6740 an unsigned multiplication of the two arguments. They return a structure
6741 &mdash; the first element of which is the multiplication, and the second
6742 element of which is a bit specifying if the unsigned multiplication resulted
6743 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6744
6745<h5>Examples:</h5>
6746<pre>
6747 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6748 %sum = extractvalue {i32, i1} %res, 0
6749 %obit = extractvalue {i32, i1} %res, 1
6750 br i1 %obit, label %overflow, label %normal
6751</pre>
6752
6753</div>
6754
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6755<!-- ======================================================================= -->
6756<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6757 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6758</div>
6759
6760<div class="doc_text">
6761
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6762<p>Half precision floating point is a storage-only format. This means that it is
6763 a dense encoding (in memory) but does not support computation in the
6764 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6765
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6766<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6767 value as an i16, then convert it to float with <a
6768 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6769 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6770 double etc). To store the value back to memory, it is first converted to
6771 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6772 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6773 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6774</div>
6775
6776<!-- _______________________________________________________________________ -->
6777<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6778 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6779</div>
6780
6781<div class="doc_text">
6782
6783<h5>Syntax:</h5>
6784<pre>
6785 declare i16 @llvm.convert.to.fp16(f32 %a)
6786</pre>
6787
6788<h5>Overview:</h5>
6789<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6790 a conversion from single precision floating point format to half precision
6791 floating point format.</p>
6792
6793<h5>Arguments:</h5>
6794<p>The intrinsic function contains single argument - the value to be
6795 converted.</p>
6796
6797<h5>Semantics:</h5>
6798<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6799 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6800 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6801 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6802
6803<h5>Examples:</h5>
6804<pre>
6805 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6806 store i16 %res, i16* @x, align 2
6807</pre>
6808
6809</div>
6810
6811<!-- _______________________________________________________________________ -->
6812<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6813 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6814</div>
6815
6816<div class="doc_text">
6817
6818<h5>Syntax:</h5>
6819<pre>
6820 declare f32 @llvm.convert.from.fp16(i16 %a)
6821</pre>
6822
6823<h5>Overview:</h5>
6824<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6825 a conversion from half precision floating point format to single precision
6826 floating point format.</p>
6827
6828<h5>Arguments:</h5>
6829<p>The intrinsic function contains single argument - the value to be
6830 converted.</p>
6831
6832<h5>Semantics:</h5>
6833<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6834 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6835 precision floating point format. The input half-float value is represented by
6836 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6837
6838<h5>Examples:</h5>
6839<pre>
6840 %a = load i16* @x, align 2
6841 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6842</pre>
6843
6844</div>
6845
6846<!-- ======================================================================= -->
6847<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6848 <a name="int_debugger">Debugger Intrinsics</a>
6849</div>
6850
6851<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6852
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6854 prefix), are described in
6855 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6856 Level Debugging</a> document.</p>
6857
6858</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6859
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6860<!-- ======================================================================= -->
6861<div class="doc_subsection">
6862 <a name="int_eh">Exception Handling Intrinsics</a>
6863</div>
6864
6865<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6866
6867<p>The LLVM exception handling intrinsics (which all start with
6868 <tt>llvm.eh.</tt> prefix), are described in
6869 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6870 Handling</a> document.</p>
6871
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6872</div>
6873
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6874<!-- ======================================================================= -->
6875<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6876 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6877</div>
6878
6879<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6880
6881<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6882 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6883 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6884 function pointer lacking the nest parameter - the caller does not need to
6885 provide a value for it. Instead, the value to use is stored in advance in a
6886 "trampoline", a block of memory usually allocated on the stack, which also
6887 contains code to splice the nest value into the argument list. This is used
6888 to implement the GCC nested function address extension.</p>
6889
6890<p>For example, if the function is
6891 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6892 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6893 follows:</p>
6894
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6895<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6896 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6897 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6898 %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]6899 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6900</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6901
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6902<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6903 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6904
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6905</div>
6906
6907<!-- _______________________________________________________________________ -->
6908<div class="doc_subsubsection">
6909 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6910</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6911
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6912<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6913
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6914<h5>Syntax:</h5>
6915<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916 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]6917</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6918
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6919<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6921 function pointer suitable for executing it.</p>
6922
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6923<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6925 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6926 sufficiently aligned block of memory; this memory is written to by the
6927 intrinsic. Note that the size and the alignment are target-specific - LLVM
6928 currently provides no portable way of determining them, so a front-end that
6929 generates this intrinsic needs to have some target-specific knowledge.
6930 The <tt>func</tt> argument must hold a function bitcast to
6931 an <tt>i8*</tt>.</p>
6932
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6933<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6935 dependent code, turning it into a function. A pointer to this function is
6936 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6937 function pointer type</a> before being called. The new function's signature
6938 is the same as that of <tt>func</tt> with any arguments marked with
6939 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6940 is allowed, and it must be of pointer type. Calling the new function is
6941 equivalent to calling <tt>func</tt> with the same argument list, but
6942 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6943 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6944 by <tt>tramp</tt> is modified, then the effect of any later call to the
6945 returned function pointer is undefined.</p>
6946
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6947</div>
6948
6949<!-- ======================================================================= -->
6950<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6951 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6952</div>
6953
6954<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6955
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6956<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6957 hardware constructs for atomic operations and memory synchronization. This
6958 provides an interface to the hardware, not an interface to the programmer. It
6959 is aimed at a low enough level to allow any programming models or APIs
6960 (Application Programming Interfaces) which need atomic behaviors to map
6961 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6962 hardware provides a "universal IR" for source languages, it also provides a
6963 starting point for developing a "universal" atomic operation and
6964 synchronization IR.</p>
6965
6966<p>These do <em>not</em> form an API such as high-level threading libraries,
6967 software transaction memory systems, atomic primitives, and intrinsic
6968 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6969 application libraries. The hardware interface provided by LLVM should allow
6970 a clean implementation of all of these APIs and parallel programming models.
6971 No one model or paradigm should be selected above others unless the hardware
6972 itself ubiquitously does so.</p>
6973
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6974</div>
6975
6976<!-- _______________________________________________________________________ -->
6977<div class="doc_subsubsection">
6978 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6979</div>
6980<div class="doc_text">
6981<h5>Syntax:</h5>
6982<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6983 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]6984</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6985
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6986<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6988 specific pairs of memory access types.</p>
6989
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6990<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6992 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6993 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6995
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6996<ul>
6997 <li><tt>ll</tt>: load-load barrier</li>
6998 <li><tt>ls</tt>: load-store barrier</li>
6999 <li><tt>sl</tt>: store-load barrier</li>
7000 <li><tt>ss</tt>: store-store barrier</li>
7001 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7002</ul>
7003
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7004<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7005<p>This intrinsic causes the system to enforce some ordering constraints upon
7006 the loads and stores of the program. This barrier does not
7007 indicate <em>when</em> any events will occur, it only enforces
7008 an <em>order</em> in which they occur. For any of the specified pairs of load
7009 and store operations (f.ex. load-load, or store-load), all of the first
7010 operations preceding the barrier will complete before any of the second
7011 operations succeeding the barrier begin. Specifically the semantics for each
7012 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014<ul>
7015 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7016 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7017 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7018 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7019 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7020 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7021 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7022 load after the barrier begins.</li>
7023</ul>
7024
7025<p>These semantics are applied with a logical "and" behavior when more than one
7026 is enabled in a single memory barrier intrinsic.</p>
7027
7028<p>Backends may implement stronger barriers than those requested when they do
7029 not support as fine grained a barrier as requested. Some architectures do
7030 not need all types of barriers and on such architectures, these become
7031 noops.</p>
7032
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7033<h5>Example:</h5>
7034<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7035%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7036%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7037 store i32 4, %ptr
7038
7039%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7040 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041 <i>; guarantee the above finishes</i>
7042 store i32 8, %ptr <i>; before this begins</i>
7043</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7044
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7045</div>
7046
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7047<!-- _______________________________________________________________________ -->
7048<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7049 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7050</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7052<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7053
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7054<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7055<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7056 any integer bit width and for different address spaces. Not all targets
7057 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7058
7059<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7060 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7061 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7062 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7063 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]7064</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7065
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7066<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7067<p>This loads a value in memory and compares it to a given value. If they are
7068 equal, it stores a new value into the memory.</p>
7069
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7070<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7072 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7073 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7074 this integer type. While any bit width integer may be used, targets may only
7075 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7076
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7078<p>This entire intrinsic must be executed atomically. It first loads the value
7079 in memory pointed to by <tt>ptr</tt> and compares it with the
7080 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7081 memory. The loaded value is yielded in all cases. This provides the
7082 equivalent of an atomic compare-and-swap operation within the SSA
7083 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7085<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7086<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7087%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7088%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7089 store i32 4, %ptr
7090
7091%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7092%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7093 <i>; yields {i32}:result1 = 4</i>
7094%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7095%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7096
7097%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7098%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7099 <i>; yields {i32}:result2 = 8</i>
7100%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7101
7102%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7103</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7104
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7105</div>
7106
7107<!-- _______________________________________________________________________ -->
7108<div class="doc_subsubsection">
7109 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7110</div>
7111<div class="doc_text">
7112<h5>Syntax:</h5>
7113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7114<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7115 integer bit width. Not all targets support all bit widths however.</p>
7116
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7117<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7118 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7119 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7120 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7121 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]7122</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7123
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7124<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7125<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7126 the value from memory. It then stores the value in <tt>val</tt> in the memory
7127 at <tt>ptr</tt>.</p>
7128
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7131 the <tt>val</tt> argument and the result must be integers of the same bit
7132 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7133 integer type. The targets may only lower integer representations they
7134 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7135
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7137<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7138 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7139 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7140
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7141<h5>Examples:</h5>
7142<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7143%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7144%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145 store i32 4, %ptr
7146
7147%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7148%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149 <i>; yields {i32}:result1 = 4</i>
7150%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7151%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7152
7153%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7154%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7155 <i>; yields {i32}:result2 = 8</i>
7156
7157%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7158%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7159</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7161</div>
7162
7163<!-- _______________________________________________________________________ -->
7164<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7165 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166
7167</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7168
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7169<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7171<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7172<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7173 any integer bit width. Not all targets support all bit widths however.</p>
7174
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7176 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7177 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7178 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7179 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]7180</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7181
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7182<h5>Overview:</h5>
7183<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7184 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7185
7186<h5>Arguments:</h5>
7187<p>The intrinsic takes two arguments, the first a pointer to an integer value
7188 and the second an integer value. The result is also an integer value. These
7189 integer types can have any bit width, but they must all have the same bit
7190 width. The targets may only lower integer representations they support.</p>
7191
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7192<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193<p>This intrinsic does a series of operations atomically. It first loads the
7194 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7195 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]7196
7197<h5>Examples:</h5>
7198<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7199%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7200%ptr = bitcast i8* %mallocP to i32*
7201 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7202%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7204%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7205 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7206%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7207 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7208%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7209</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211</div>
7212
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7213<!-- _______________________________________________________________________ -->
7214<div class="doc_subsubsection">
7215 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7216
7217</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7219<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7220
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7221<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7222<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7223 any integer bit width and for different address spaces. Not all targets
7224 support all bit widths however.</p>
7225
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7226<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7227 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7228 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7229 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7230 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]7231</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7232
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7233<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7234<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7235 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7236
7237<h5>Arguments:</h5>
7238<p>The intrinsic takes two arguments, the first a pointer to an integer value
7239 and the second an integer value. The result is also an integer value. These
7240 integer types can have any bit width, but they must all have the same bit
7241 width. The targets may only lower integer representations they support.</p>
7242
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7243<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7244<p>This intrinsic does a series of operations atomically. It first loads the
7245 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7246 result to <tt>ptr</tt>. It yields the original value stored
7247 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7248
7249<h5>Examples:</h5>
7250<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7251%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7252%ptr = bitcast i8* %mallocP to i32*
7253 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7254%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7255 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7256%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7257 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7258%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7259 <i>; yields {i32}:result3 = 2</i>
7260%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7261</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7262
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7263</div>
7264
7265<!-- _______________________________________________________________________ -->
7266<div class="doc_subsubsection">
7267 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7268 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7269 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7270 <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]7271</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7272
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7273<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7274
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7275<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276<p>These are overloaded intrinsics. You can
7277 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7278 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7279 bit width and for different address spaces. Not all targets support all bit
7280 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7281
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7282<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7283 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7284 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7285 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7286 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]7287</pre>
7288
7289<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7290 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7291 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7292 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7293 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]7294</pre>
7295
7296<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7297 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7298 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7299 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7300 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]7301</pre>
7302
7303<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7304 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7305 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7306 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7307 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]7308</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7309
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7310<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7312 the value stored in memory at <tt>ptr</tt>. It yields the original value
7313 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7314
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7315<h5>Arguments:</h5>
7316<p>These intrinsics take two arguments, the first a pointer to an integer value
7317 and the second an integer value. The result is also an integer value. These
7318 integer types can have any bit width, but they must all have the same bit
7319 width. The targets may only lower integer representations they support.</p>
7320
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7321<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7322<p>These intrinsics does a series of operations atomically. They first load the
7323 value stored at <tt>ptr</tt>. They then do the bitwise
7324 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7325 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7326
7327<h5>Examples:</h5>
7328<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7329%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7330%ptr = bitcast i8* %mallocP to i32*
7331 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7332%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7333 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7334%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7335 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7336%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7337 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7338%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7339 <i>; yields {i32}:result3 = FF</i>
7340%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7341</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7343</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7344
7345<!-- _______________________________________________________________________ -->
7346<div class="doc_subsubsection">
7347 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7348 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7349 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7350 <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]7351</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7353<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7354
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7355<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7356<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7357 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7358 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7359 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7360
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7361<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7362 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7363 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7364 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7365 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]7366</pre>
7367
7368<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7369 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7370 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7371 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7372 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]7373</pre>
7374
7375<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7376 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7377 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7378 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7379 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]7380</pre>
7381
7382<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7383 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7384 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7385 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7386 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]7387</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7389<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7390<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7392 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7394<h5>Arguments:</h5>
7395<p>These intrinsics take two arguments, the first a pointer to an integer value
7396 and the second an integer value. The result is also an integer value. These
7397 integer types can have any bit width, but they must all have the same bit
7398 width. The targets may only lower integer representations they support.</p>
7399
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7400<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7401<p>These intrinsics does a series of operations atomically. They first load the
7402 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7403 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7404 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7405
7406<h5>Examples:</h5>
7407<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7408%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7409%ptr = bitcast i8* %mallocP to i32*
7410 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7411%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7413%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7414 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7415%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7416 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7417%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7418 <i>; yields {i32}:result3 = 8</i>
7419%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7420</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7422</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7423
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7424
7425<!-- ======================================================================= -->
7426<div class="doc_subsection">
7427 <a name="int_memorymarkers">Memory Use Markers</a>
7428</div>
7429
7430<div class="doc_text">
7431
7432<p>This class of intrinsics exists to information about the lifetime of memory
7433 objects and ranges where variables are immutable.</p>
7434
7435</div>
7436
7437<!-- _______________________________________________________________________ -->
7438<div class="doc_subsubsection">
7439 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7440</div>
7441
7442<div class="doc_text">
7443
7444<h5>Syntax:</h5>
7445<pre>
7446 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7447</pre>
7448
7449<h5>Overview:</h5>
7450<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7451 object's lifetime.</p>
7452
7453<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7454<p>The first argument is a constant integer representing the size of the
7455 object, or -1 if it is variable sized. The second argument is a pointer to
7456 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7457
7458<h5>Semantics:</h5>
7459<p>This intrinsic indicates that before this point in the code, the value of the
7460 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]7461 never be used and has an undefined value. A load from the pointer that
7462 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7463 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7464
7465</div>
7466
7467<!-- _______________________________________________________________________ -->
7468<div class="doc_subsubsection">
7469 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7470</div>
7471
7472<div class="doc_text">
7473
7474<h5>Syntax:</h5>
7475<pre>
7476 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7477</pre>
7478
7479<h5>Overview:</h5>
7480<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end 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 after 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
7491 never be used and has an undefined value. Any stores into the memory object
7492 following this intrinsic may be removed as dead.
7493
7494</div>
7495
7496<!-- _______________________________________________________________________ -->
7497<div class="doc_subsubsection">
7498 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7499</div>
7500
7501<div class="doc_text">
7502
7503<h5>Syntax:</h5>
7504<pre>
7505 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7506</pre>
7507
7508<h5>Overview:</h5>
7509<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7510 a memory object will not change.</p>
7511
7512<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7513<p>The first argument is a constant integer representing the size of the
7514 object, or -1 if it is variable sized. The second argument is a pointer to
7515 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7516
7517<h5>Semantics:</h5>
7518<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7519 the return value, the referenced memory location is constant and
7520 unchanging.</p>
7521
7522</div>
7523
7524<!-- _______________________________________________________________________ -->
7525<div class="doc_subsubsection">
7526 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7527</div>
7528
7529<div class="doc_text">
7530
7531<h5>Syntax:</h5>
7532<pre>
7533 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7534</pre>
7535
7536<h5>Overview:</h5>
7537<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7538 a memory object are mutable.</p>
7539
7540<h5>Arguments:</h5>
7541<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7542 The second argument is a constant integer representing the size of the
7543 object, or -1 if it is variable sized and the third argument is a pointer
7544 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7545
7546<h5>Semantics:</h5>
7547<p>This intrinsic indicates that the memory is mutable again.</p>
7548
7549</div>
7550
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7551<!-- ======================================================================= -->
7552<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7553 <a name="int_general">General Intrinsics</a>
7554</div>
7555
7556<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7557
7558<p>This class of intrinsics is designed to be generic and has no specific
7559 purpose.</p>
7560
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7561</div>
7562
7563<!-- _______________________________________________________________________ -->
7564<div class="doc_subsubsection">
7565 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7566</div>
7567
7568<div class="doc_text">
7569
7570<h5>Syntax:</h5>
7571<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7572 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]7573</pre>
7574
7575<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7576<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7577
7578<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7579<p>The first argument is a pointer to a value, the second is a pointer to a
7580 global string, the third is a pointer to a global string which is the source
7581 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7582
7583<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7584<p>This intrinsic allows annotation of local variables with arbitrary strings.
7585 This can be useful for special purpose optimizations that want to look for
7586 these annotations. These have no other defined use, they are ignored by code
7587 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7588
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7589</div>
7590
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7591<!-- _______________________________________________________________________ -->
7592<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7593 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7594</div>
7595
7596<div class="doc_text">
7597
7598<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7599<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7600 any integer bit width.</p>
7601
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7602<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7603 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7604 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7605 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7606 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7607 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]7608</pre>
7609
7610<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7611<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7612
7613<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7614<p>The first argument is an integer value (result of some expression), the
7615 second is a pointer to a global string, the third is a pointer to a global
7616 string which is the source file name, and the last argument is the line
7617 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7618
7619<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7620<p>This intrinsic allows annotations to be put on arbitrary expressions with
7621 arbitrary strings. This can be useful for special purpose optimizations that
7622 want to look for these annotations. These have no other defined use, they
7623 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7624
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7625</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7626
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7627<!-- _______________________________________________________________________ -->
7628<div class="doc_subsubsection">
7629 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7630</div>
7631
7632<div class="doc_text">
7633
7634<h5>Syntax:</h5>
7635<pre>
7636 declare void @llvm.trap()
7637</pre>
7638
7639<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7640<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7641
7642<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7643<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7644
7645<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7646<p>This intrinsics is lowered to the target dependent trap instruction. If the
7647 target does not have a trap instruction, this intrinsic will be lowered to
7648 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7649
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7650</div>
7651
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7652<!-- _______________________________________________________________________ -->
7653<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7654 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7655</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7656
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7657<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7658
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7659<h5>Syntax:</h5>
7660<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7661 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7663
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7666 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7667 ensure that it is placed on the stack before local variables.</p>
7668
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7669<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7670<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7671 arguments. The first argument is the value loaded from the stack
7672 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7673 that has enough space to hold the value of the guard.</p>
7674
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7675<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7676<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7677 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7678 stack. This is to ensure that if a local variable on the stack is
7679 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7680 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7681 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7682 function.</p>
7683
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7684</div>
7685
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7686<!-- _______________________________________________________________________ -->
7687<div class="doc_subsubsection">
7688 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7689</div>
7690
7691<div class="doc_text">
7692
7693<h5>Syntax:</h5>
7694<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7695 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7696 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7697</pre>
7698
7699<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7700<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7701 the optimizers to determine at compile time whether a) an operation (like
7702 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7703 runtime check for overflow isn't necessary. An object in this context means
7704 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7705
7706<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7707<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7708 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7709 is a boolean 0 or 1. This argument determines whether you want the
7710 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7711 1, variables are not allowed.</p>
7712
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7713<h5>Semantics:</h5>
7714<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7715 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7716 depending on the <tt>type</tt> argument, if the size cannot be determined at
7717 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7718
7719</div>
7720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7721<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7722<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7723<address>
7724 <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]7728
7729 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7730 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7731 Last modified: $Date$
7732</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7734</body>
7735</html>