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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / a6fd81dd7f6039fbc1a55f6f4d45659fffdd81fb / . / 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>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame^]1024 <dd><p>This indicates that the pointer parameter should really be passed by
1025 value to the function. The attribute implies that a hidden copy of the
1026 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027 is made between the caller and the callee, so the callee is unable to
1028 modify the value in the callee. This attribute is only valid on LLVM
1029 pointer arguments. It is generally used to pass structs and arrays by
1030 value, but is also valid on pointers to scalars. The copy is considered
1031 to belong to the caller not the callee (for example,
1032 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1033 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame^]1034 values.</p>
1035
1036 <p>The byval attribute also supports specifying an alignment with
1037 the align attribute. It indicates the alignment of the stack slot to
1038 form and the known alignment of the pointer specified to the call site. If
1039 the alignment is not specified, then the code generator makes a
1040 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1042 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1043 <dd>This indicates that the pointer parameter specifies the address of a
1044 structure that is the return value of the function in the source program.
1045 This pointer must be guaranteed by the caller to be valid: loads and
1046 stores to the structure may be assumed by the callee to not to trap. This
1047 may only be applied to the first parameter. This is not a valid attribute
1048 for return values. </dd>
1049
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1050 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1051 <dd>This indicates that pointer values
1052 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1053 value do not alias pointer values which are not <i>based</i> on it,
1054 ignoring certain "irrelevant" dependencies.
1055 For a call to the parent function, dependencies between memory
1056 references from before or after the call and from those during the call
1057 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1058 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1059 The caller shares the responsibility with the callee for ensuring that
1060 these requirements are met.
1061 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1062 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1063<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1064 Note that this definition of <tt>noalias</tt> is intentionally
1065 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1066 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1067<br>
1068 For function return values, C99's <tt>restrict</tt> is not meaningful,
1069 while LLVM's <tt>noalias</tt> is.
1070 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1072 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1073 <dd>This indicates that the callee does not make any copies of the pointer
1074 that outlive the callee itself. This is not a valid attribute for return
1075 values.</dd>
1076
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1077 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078 <dd>This indicates that the pointer parameter can be excised using the
1079 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1080 attribute for return values.</dd>
1081</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1082
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1083</div>
1084
1085<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1086<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087 <a name="gc">Garbage Collector Names</a>
1088</div>
1089
1090<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092<p>Each function may specify a garbage collector name, which is simply a
1093 string:</p>
1094
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1095<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1096define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1097</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1098
1099<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100 collector which will cause the compiler to alter its output in order to
1101 support the named garbage collection algorithm.</p>
1102
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1103</div>
1104
1105<!-- ======================================================================= -->
1106<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1108</div>
1109
1110<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1111
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112<p>Function attributes are set to communicate additional information about a
1113 function. Function attributes are considered to be part of the function, not
1114 of the function type, so functions with different parameter attributes can
1115 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1117<p>Function attributes are simple keywords that follow the type specified. If
1118 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1119
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1120<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1121define void @f() noinline { ... }
1122define void @f() alwaysinline { ... }
1123define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1124define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1125</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1126
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1127<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1128 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1129 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1130 the backend should forcibly align the stack pointer. Specify the
1131 desired alignment, which must be a power of two, in parentheses.
1132
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should attempt to inline this
1135 function into callers whenever possible, ignoring any active inlining size
1136 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1137
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1138 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1139 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1140 meaning the function can be patched and/or hooked even while it is
1141 loaded into memory. On x86, the function prologue will be preceded
1142 by six bytes of padding and will begin with a two-byte instruction.
1143 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1144 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1145
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1146 <dt><tt><b>inlinehint</b></tt></dt>
1147 <dd>This attribute indicates that the source code contained a hint that inlining
1148 this function is desirable (such as the "inline" keyword in C/C++). It
1149 is just a hint; it imposes no requirements on the inliner.</dd>
1150
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1151 <dt><tt><b>naked</b></tt></dt>
1152 <dd>This attribute disables prologue / epilogue emission for the function.
1153 This can have very system-specific consequences.</dd>
1154
1155 <dt><tt><b>noimplicitfloat</b></tt></dt>
1156 <dd>This attributes disables implicit floating point instructions.</dd>
1157
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the inliner should never inline this
1160 function in any situation. This attribute may not be used together with
1161 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1162
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1163 <dt><tt><b>noredzone</b></tt></dt>
1164 <dd>This attribute indicates that the code generator should not use a red
1165 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1166
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1167 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1168 <dd>This function attribute indicates that the function never returns
1169 normally. This produces undefined behavior at runtime if the function
1170 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1171
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1172 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1173 <dd>This function attribute indicates that the function never returns with an
1174 unwind or exceptional control flow. If the function does unwind, its
1175 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1176
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1177 <dt><tt><b>optsize</b></tt></dt>
1178 <dd>This attribute suggests that optimization passes and code generator passes
1179 make choices that keep the code size of this function low, and otherwise
1180 do optimizations specifically to reduce code size.</dd>
1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This attribute indicates that the function computes its result (or decides
1184 to unwind an exception) based strictly on its arguments, without
1185 dereferencing any pointer arguments or otherwise accessing any mutable
1186 state (e.g. memory, control registers, etc) visible to caller functions.
1187 It does not write through any pointer arguments
1188 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1189 changes any state visible to callers. This means that it cannot unwind
1190 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1191 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1192
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1193 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1194 <dd>This attribute indicates that the function does not write through any
1195 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1196 arguments) or otherwise modify any state (e.g. memory, control registers,
1197 etc) visible to caller functions. It may dereference pointer arguments
1198 and read state that may be set in the caller. A readonly function always
1199 returns the same value (or unwinds an exception identically) when called
1200 with the same set of arguments and global state. It cannot unwind an
1201 exception by calling the <tt>C++</tt> exception throwing methods, but may
1202 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1203
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1204 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1205 <dd>This attribute indicates that the function should emit a stack smashing
1206 protector. It is in the form of a "canary"&mdash;a random value placed on
1207 the stack before the local variables that's checked upon return from the
1208 function to see if it has been overwritten. A heuristic is used to
1209 determine if a function needs stack protectors or not.<br>
1210<br>
1211 If a function that has an <tt>ssp</tt> attribute is inlined into a
1212 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1213 function will have an <tt>ssp</tt> attribute.</dd>
1214
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1215 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 <dd>This attribute indicates that the function should <em>always</em> emit a
1217 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1218 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1219<br>
1220 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1221 function that doesn't have an <tt>sspreq</tt> attribute or which has
1222 an <tt>ssp</tt> attribute, then the resulting function will have
1223 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1224</dl>
1225
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1226</div>
1227
1228<!-- ======================================================================= -->
1229<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1230 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1231</div>
1232
1233<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1234
1235<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1236 the GCC "file scope inline asm" blocks. These blocks are internally
1237 concatenated by LLVM and treated as a single unit, but may be separated in
1238 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1239
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1240<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1241module asm "inline asm code goes here"
1242module asm "more can go here"
1243</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1244
1245<p>The strings can contain any character by escaping non-printable characters.
1246 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]1247 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1248
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1249<p>The inline asm code is simply printed to the machine code .s file when
1250 assembly code is generated.</p>
1251
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1252</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1253
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1254<!-- ======================================================================= -->
1255<div class="doc_subsection">
1256 <a name="datalayout">Data Layout</a>
1257</div>
1258
1259<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1260
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1261<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262 data is to be laid out in memory. The syntax for the data layout is
1263 simply:</p>
1264
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1265<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1266target datalayout = "<i>layout specification</i>"
1267</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1268
1269<p>The <i>layout specification</i> consists of a list of specifications
1270 separated by the minus sign character ('-'). Each specification starts with
1271 a letter and may include other information after the letter to define some
1272 aspect of the data layout. The specifications accepted are as follows:</p>
1273
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1274<dl>
1275 <dt><tt>E</tt></dt>
1276 <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]1277 bits with the most significance have the lowest address location.</dd>
1278
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1279 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1280 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1281 the bits with the least significance have the lowest address
1282 location.</dd>
1283
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1285 <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]1286 <i>preferred</i> alignments. All sizes are in bits. Specifying
1287 the <i>pref</i> alignment is optional. If omitted, the
1288 preceding <tt>:</tt> should be omitted too.</dd>
1289
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1290 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1291 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1293
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1294 <dt><tt>v<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 vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1296 <i>size</i>.</dd>
1297
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1298 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1299 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1300 <i>size</i>. Only values of <i>size</i> that are supported by the target
1301 will work. 32 (float) and 64 (double) are supported on all targets;
1302 80 or 128 (different flavors of long double) are also supported on some
1303 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1306 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 <i>size</i>.</dd>
1308
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1309 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1310 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1311 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1312
1313 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1314 <dd>This specifies a set of native integer widths for the target CPU
1315 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1316 "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]1317 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1318 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1320
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1321<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1322 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1323 specifications in the <tt>datalayout</tt> keyword. The default specifications
1324 are given in this list:</p>
1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326<ul>
1327 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1328 <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]1329 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1330 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1331 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1332 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1333 <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]1334 alignment of 64-bits</li>
1335 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1336 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1337 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1338 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1339 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1340 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1341</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1342
1343<p>When LLVM is determining the alignment for a given type, it uses the
1344 following rules:</p>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346<ol>
1347 <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]1348 specification is used.</li>
1349
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1350 <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]1351 smallest integer type that is larger than the bitwidth of the sought type
1352 is used. If none of the specifications are larger than the bitwidth then
1353 the the largest integer type is used. For example, given the default
1354 specifications above, the i7 type will use the alignment of i8 (next
1355 largest) while both i65 and i256 will use the alignment of i64 (largest
1356 specified).</li>
1357
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358 <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]1359 largest vector type that is smaller than the sought vector type will be
1360 used as a fall back. This happens because &lt;128 x double&gt; can be
1361 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1362</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1363
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1364</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1365
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1366<!-- ======================================================================= -->
1367<div class="doc_subsection">
1368 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1369</div>
1370
1371<div class="doc_text">
1372
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1373<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1374with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1375is undefined. Pointer values are associated with address ranges
1376according to the following rules:</p>
1377
1378<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1379 <li>A pointer value is associated with the addresses associated with
1380 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1381 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1382 range of the variable's storage.</li>
1383 <li>The result value of an allocation instruction is associated with
1384 the address range of the allocated storage.</li>
1385 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1386 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1387 <li>An integer constant other than zero or a pointer value returned
1388 from a function not defined within LLVM may be associated with address
1389 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1390 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1391 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1392</ul>
1393
1394<p>A pointer value is <i>based</i> on another pointer value according
1395 to the following rules:</p>
1396
1397<ul>
1398 <li>A pointer value formed from a
1399 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1400 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1401 <li>The result value of a
1402 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1403 of the <tt>bitcast</tt>.</li>
1404 <li>A pointer value formed by an
1405 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1406 pointer values that contribute (directly or indirectly) to the
1407 computation of the pointer's value.</li>
1408 <li>The "<i>based</i> on" relationship is transitive.</li>
1409</ul>
1410
1411<p>Note that this definition of <i>"based"</i> is intentionally
1412 similar to the definition of <i>"based"</i> in C99, though it is
1413 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1414
1415<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1416<tt><a href="#i_load">load</a></tt> merely indicates the size and
1417alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1418interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1419<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1420and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
1422<p>Consequently, type-based alias analysis, aka TBAA, aka
1423<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1424LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1425additional information which specialized optimization passes may use
1426to implement type-based alias analysis.</p>
1427
1428</div>
1429
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1430<!-- ======================================================================= -->
1431<div class="doc_subsection">
1432 <a name="volatile">Volatile Memory Accesses</a>
1433</div>
1434
1435<div class="doc_text">
1436
1437<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1438href="#i_store"><tt>store</tt></a>s, and <a
1439href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1440The optimizers must not change the number of volatile operations or change their
1441order of execution relative to other volatile operations. The optimizers
1442<i>may</i> change the order of volatile operations relative to non-volatile
1443operations. This is not Java's "volatile" and has no cross-thread
1444synchronization behavior.</p>
1445
1446</div>
1447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1448<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1449<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1450<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1451
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1452<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1454<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1455 intermediate representation. Being typed enables a number of optimizations
1456 to be performed on the intermediate representation directly, without having
1457 to do extra analyses on the side before the transformation. A strong type
1458 system makes it easier to read the generated code and enables novel analyses
1459 and transformations that are not feasible to perform on normal three address
1460 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1461
1462</div>
1463
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1464<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1465<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1466Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1468<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1469
1470<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1471
1472<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1473 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1474 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1475 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1477 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478 </tr>
1479 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1480 <td><a href="#t_floating">floating point</a></td>
1481 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1482 </tr>
1483 <tr>
1484 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1485 <td><a href="#t_integer">integer</a>,
1486 <a href="#t_floating">floating point</a>,
1487 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1488 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1489 <a href="#t_struct">structure</a>,
1490 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1491 <a href="#t_label">label</a>,
1492 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1493 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1494 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1495 <tr>
1496 <td><a href="#t_primitive">primitive</a></td>
1497 <td><a href="#t_label">label</a>,
1498 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1499 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1500 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1501 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502 </tr>
1503 <tr>
1504 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1505 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506 <a href="#t_function">function</a>,
1507 <a href="#t_pointer">pointer</a>,
1508 <a href="#t_struct">structure</a>,
1509 <a href="#t_pstruct">packed structure</a>,
1510 <a href="#t_vector">vector</a>,
1511 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1512 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1513 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1514 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1515</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1517<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1518 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1519 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1520
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1521</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1522
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1523<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1524<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1525
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1527
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1528<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1529 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1530
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1531</div>
1532
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1533<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1534<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1535
1536<div class="doc_text">
1537
1538<h5>Overview:</h5>
1539<p>The integer type is a very simple type that simply specifies an arbitrary
1540 bit width for the integer type desired. Any bit width from 1 bit to
1541 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1542
1543<h5>Syntax:</h5>
1544<pre>
1545 iN
1546</pre>
1547
1548<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1549 value.</p>
1550
1551<h5>Examples:</h5>
1552<table class="layout">
1553 <tr class="layout">
1554 <td class="left"><tt>i1</tt></td>
1555 <td class="left">a single-bit integer.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>i32</tt></td>
1559 <td class="left">a 32-bit integer.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>i1942652</tt></td>
1563 <td class="left">a really big integer of over 1 million bits.</td>
1564 </tr>
1565</table>
1566
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1567</div>
1568
1569<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1570<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1571
1572<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1573
1574<table>
1575 <tbody>
1576 <tr><th>Type</th><th>Description</th></tr>
1577 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1578 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1579 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1580 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1581 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1582 </tbody>
1583</table>
1584
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1585</div>
1586
1587<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1588<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1589
1590<div class="doc_text">
1591
1592<h5>Overview:</h5>
1593<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>
1594
1595<h5>Syntax:</h5>
1596<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1597 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1598</pre>
1599
1600</div>
1601
1602<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1603<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1604
1605<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1606
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607<h5>Overview:</h5>
1608<p>The void type does not represent any value and has no size.</p>
1609
1610<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1611<pre>
1612 void
1613</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1614
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1615</div>
1616
1617<!-- _______________________________________________________________________ -->
1618<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1619
1620<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1621
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<h5>Overview:</h5>
1623<p>The label type represents code labels.</p>
1624
1625<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626<pre>
1627 label
1628</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1629
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1630</div>
1631
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1632<!-- _______________________________________________________________________ -->
1633<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1634
1635<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1636
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1637<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1638<p>The metadata type represents embedded metadata. No derived types may be
1639 created from metadata except for <a href="#t_function">function</a>
1640 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1641
1642<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1643<pre>
1644 metadata
1645</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1646
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1647</div>
1648
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1649
1650<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1651<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1652
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1653<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1654
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1655<p>The real power in LLVM comes from the derived types in the system. This is
1656 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1657 useful types. Each of these types contain one or more element types which
1658 may be a primitive type, or another derived type. For example, it is
1659 possible to have a two dimensional array, using an array as the element type
1660 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1661
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1662
1663</div>
1664
1665<!-- _______________________________________________________________________ -->
1666<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1667
1668<div class="doc_text">
1669
1670<p>Aggregate Types are a subset of derived types that can contain multiple
1671 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1672 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1673 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1674
1675</div>
1676
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1677<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1678<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1679
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1680<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1681
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1682<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1684 sequentially in memory. The array type requires a size (number of elements)
1685 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1686
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1687<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1688<pre>
1689 [&lt;# elements&gt; x &lt;elementtype&gt;]
1690</pre>
1691
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1692<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1693 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1695<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1696<table class="layout">
1697 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1698 <td class="left"><tt>[40 x i32]</tt></td>
1699 <td class="left">Array of 40 32-bit integer values.</td>
1700 </tr>
1701 <tr class="layout">
1702 <td class="left"><tt>[41 x i32]</tt></td>
1703 <td class="left">Array of 41 32-bit integer values.</td>
1704 </tr>
1705 <tr class="layout">
1706 <td class="left"><tt>[4 x i8]</tt></td>
1707 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1708 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1709</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1710<p>Here are some examples of multidimensional arrays:</p>
1711<table class="layout">
1712 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1713 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1714 <td class="left">3x4 array of 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1718 <td class="left">12x10 array of single precision floating point values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1722 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1723 </tr>
1724</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1725
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1726<p>There is no restriction on indexing beyond the end of the array implied by
1727 a static type (though there are restrictions on indexing beyond the bounds
1728 of an allocated object in some cases). This means that single-dimension
1729 'variable sized array' addressing can be implemented in LLVM with a zero
1730 length array type. An implementation of 'pascal style arrays' in LLVM could
1731 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1732
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1733</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1734
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1738<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1739
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1741<p>The function type can be thought of as a function signature. It consists of
1742 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]1743 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1744
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1745<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1746<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1747 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1748</pre>
1749
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1750<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]1751 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1752 which indicates that the function takes a variable number of arguments.
1753 Variable argument functions can access their arguments with
1754 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1755 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1756 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1757
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1759<table class="layout">
1760 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1761 <td class="left"><tt>i32 (i32)</tt></td>
1762 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1763 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1764 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1765 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1766 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1767 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1768 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1769 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1770 </td>
1771 </tr><tr class="layout">
1772 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1773 <td class="left">A vararg function that takes at least one
1774 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1775 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1776 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1777 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1778 </tr><tr class="layout">
1779 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1780 <td class="left">A function taking an <tt>i32</tt>, returning a
1781 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1782 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1790
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1791<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1794<p>The structure type is used to represent a collection of data members together
1795 in memory. The packing of the field types is defined to match the ABI of the
1796 underlying processor. The elements of a structure may be any type that has a
1797 size.</p>
1798
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1799<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1800 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1801 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1802 Structures in registers are accessed using the
1803 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1804 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1806<pre>
1807 { &lt;type list&gt; }
1808</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1810<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1811<table class="layout">
1812 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1813 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1814 <td class="left">A triple of three <tt>i32</tt> values</td>
1815 </tr><tr class="layout">
1816 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1821 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1823
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1828</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1829
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1830<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1831
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1832<h5>Overview:</h5>
1833<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1834 together in memory. There is no padding between fields. Further, the
1835 alignment of a packed structure is 1 byte. The elements of a packed
1836 structure may be any type that has a size.</p>
1837
1838<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1839 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1840 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1841
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1842<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1843<pre>
1844 &lt; { &lt;type list&gt; } &gt;
1845</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1846
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1847<h5>Examples:</h5>
1848<table class="layout">
1849 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1850 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1851 <td class="left">A triple of three <tt>i32</tt> values</td>
1852 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1853 <td class="left">
1854<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1855 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1856 second element is a <a href="#t_pointer">pointer</a> to a
1857 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1858 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1859 </tr>
1860</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1861
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1862</div>
1863
1864<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1865<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1867<div class="doc_text">
1868
1869<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1870<p>The pointer type is used to specify memory locations.
1871 Pointers are commonly used to reference objects in memory.</p>
1872
1873<p>Pointer types may have an optional address space attribute defining the
1874 numbered address space where the pointed-to object resides. The default
1875 address space is number zero. The semantics of non-zero address
1876 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1877
1878<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1879 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1880
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1881<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1882<pre>
1883 &lt;type&gt; *
1884</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1885
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1886<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1887<table class="layout">
1888 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1889 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1890 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1891 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1892 </tr>
1893 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1894 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1895 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1896 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1897 <tt>i32</tt>.</td>
1898 </tr>
1899 <tr class="layout">
1900 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1901 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1902 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1903 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1904</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1905
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1906</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1907
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1908<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1909<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1911<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1912
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914<p>A vector type is a simple derived type that represents a vector of elements.
1915 Vector types are used when multiple primitive data are operated in parallel
1916 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1917 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1919
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1920<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1921<pre>
1922 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1923</pre>
1924
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1925<p>The number of elements is a constant integer value larger than 0; elementtype
1926 may be any integer or floating point type. Vectors of size zero are not
1927 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1930<table class="layout">
1931 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1932 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1933 <td class="left">Vector of 4 32-bit integer values.</td>
1934 </tr>
1935 <tr class="layout">
1936 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1937 <td class="left">Vector of 8 32-bit floating-point values.</td>
1938 </tr>
1939 <tr class="layout">
1940 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1941 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1942 </tr>
1943</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1944
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945</div>
1946
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1947<!-- _______________________________________________________________________ -->
1948<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1949<div class="doc_text">
1950
1951<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1952<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1953 corresponds (for example) to the C notion of a forward declared structure
1954 type. In LLVM, opaque types can eventually be resolved to any type (not just
1955 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1956
1957<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1958<pre>
1959 opaque
1960</pre>
1961
1962<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1963<table class="layout">
1964 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1965 <td class="left"><tt>opaque</tt></td>
1966 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967 </tr>
1968</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1969
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1970</div>
1971
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1972<!-- ======================================================================= -->
1973<div class="doc_subsection">
1974 <a name="t_uprefs">Type Up-references</a>
1975</div>
1976
1977<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1979<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1980<p>An "up reference" allows you to refer to a lexically enclosing type without
1981 requiring it to have a name. For instance, a structure declaration may
1982 contain a pointer to any of the types it is lexically a member of. Example
1983 of up references (with their equivalent as named type declarations)
1984 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1985
1986<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1987 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1988 { \2 }* %y = type { %y }*
1989 \1* %z = type %z*
1990</pre>
1991
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1992<p>An up reference is needed by the asmprinter for printing out cyclic types
1993 when there is no declared name for a type in the cycle. Because the
1994 asmprinter does not want to print out an infinite type string, it needs a
1995 syntax to handle recursive types that have no names (all names are optional
1996 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1997
1998<h5>Syntax:</h5>
1999<pre>
2000 \&lt;level&gt;
2001</pre>
2002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2003<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]2004
2005<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2006<table class="layout">
2007 <tr class="layout">
2008 <td class="left"><tt>\1*</tt></td>
2009 <td class="left">Self-referential pointer.</td>
2010 </tr>
2011 <tr class="layout">
2012 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2013 <td class="left">Recursive structure where the upref refers to the out-most
2014 structure.</td>
2015 </tr>
2016</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2018</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2019
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2020<!-- *********************************************************************** -->
2021<div class="doc_section"> <a name="constants">Constants</a> </div>
2022<!-- *********************************************************************** -->
2023
2024<div class="doc_text">
2025
2026<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2027 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2028
2029</div>
2030
2031<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2032<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2033
2034<div class="doc_text">
2035
2036<dl>
2037 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2038 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2039 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2040
2041 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042 <dd>Standard integers (such as '4') are constants of
2043 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2044 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2045
2046 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2047 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2048 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2049 notation (see below). The assembler requires the exact decimal value of a
2050 floating-point constant. For example, the assembler accepts 1.25 but
2051 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2052 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2055 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2056 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2057</dl>
2058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2059<p>The one non-intuitive notation for constants is the hexadecimal form of
2060 floating point constants. For example, the form '<tt>double
2061 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2062 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2063 constants are required (and the only time that they are generated by the
2064 disassembler) is when a floating point constant must be emitted but it cannot
2065 be represented as a decimal floating point number in a reasonable number of
2066 digits. For example, NaN's, infinities, and other special values are
2067 represented in their IEEE hexadecimal format so that assembly and disassembly
2068 do not cause any bits to change in the constants.</p>
2069
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2070<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071 represented using the 16-digit form shown above (which matches the IEEE754
2072 representation for double); float values must, however, be exactly
2073 representable as IEE754 single precision. Hexadecimal format is always used
2074 for long double, and there are three forms of long double. The 80-bit format
2075 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2076 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2077 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2078 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2079 currently supported target uses this format. Long doubles will only work if
2080 they match the long double format on your target. All hexadecimal formats
2081 are big-endian (sign bit at the left).</p>
2082
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2083<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2084</div>
2085
2086<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2087<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2088<a name="aggregateconstants"></a> <!-- old anchor -->
2089<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2090</div>
2091
2092<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2093
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2094<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2095 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2096
2097<dl>
2098 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100 type definitions (a comma separated list of elements, surrounded by braces
2101 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2102 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2103 Structure constants must have <a href="#t_struct">structure type</a>, and
2104 the number and types of elements must match those specified by the
2105 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2106
2107 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2108 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2109 definitions (a comma separated list of elements, surrounded by square
2110 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2111 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2112 the number and types of elements must match those specified by the
2113 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2114
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2115 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2116 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2117 definitions (a comma separated list of elements, surrounded by
2118 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2119 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2120 have <a href="#t_vector">vector type</a>, and the number and types of
2121 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2122
2123 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2124 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2125 value to zero of <em>any</em> type, including scalar and
2126 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2127 This is often used to avoid having to print large zero initializers
2128 (e.g. for large arrays) and is always exactly equivalent to using explicit
2129 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2130
2131 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2132 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2133 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2134 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2135 be interpreted as part of the instruction stream, metadata is a place to
2136 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137</dl>
2138
2139</div>
2140
2141<!-- ======================================================================= -->
2142<div class="doc_subsection">
2143 <a name="globalconstants">Global Variable and Function Addresses</a>
2144</div>
2145
2146<div class="doc_text">
2147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148<p>The addresses of <a href="#globalvars">global variables</a>
2149 and <a href="#functionstructure">functions</a> are always implicitly valid
2150 (link-time) constants. These constants are explicitly referenced when
2151 the <a href="#identifiers">identifier for the global</a> is used and always
2152 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2153 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2154
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2155<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2156@X = global i32 17
2157@Y = global i32 42
2158@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2159</pre>
2160
2161</div>
2162
2163<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2164<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2165<div class="doc_text">
2166
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2167<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]2168 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2169 Undefined values may be of any type (other than '<tt>label</tt>'
2170 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2171
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2172<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2173 program is well defined no matter what value is used. This gives the
2174 compiler more freedom to optimize. Here are some examples of (potentially
2175 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2176
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2177
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2178<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2179 %A = add %X, undef
2180 %B = sub %X, undef
2181 %C = xor %X, undef
2182Safe:
2183 %A = undef
2184 %B = undef
2185 %C = undef
2186</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2187
2188<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]2189 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]2190
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2191<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2192 %A = or %X, undef
2193 %B = and %X, undef
2194Safe:
2195 %A = -1
2196 %B = 0
2197Unsafe:
2198 %A = undef
2199 %B = undef
2200</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2201
2202<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2203 For example, if <tt>%X</tt> has a zero bit, then the output of the
2204 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2205 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2206 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2207 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2208 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2209 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2210 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2211
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2212<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2213 %A = select undef, %X, %Y
2214 %B = select undef, 42, %Y
2215 %C = select %X, %Y, undef
2216Safe:
2217 %A = %X (or %Y)
2218 %B = 42 (or %Y)
2219 %C = %Y
2220Unsafe:
2221 %A = undef
2222 %B = undef
2223 %C = undef
2224</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2225
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2226<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2227 branch) conditions can go <em>either way</em>, but they have to come from one
2228 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2229 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2230 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2231 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2232 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2233 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2234
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2235<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2236 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2237
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2238 %B = undef
2239 %C = xor %B, %B
2240
2241 %D = undef
2242 %E = icmp lt %D, 4
2243 %F = icmp gte %D, 4
2244
2245Safe:
2246 %A = undef
2247 %B = undef
2248 %C = undef
2249 %D = undef
2250 %E = undef
2251 %F = undef
2252</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2253
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2254<p>This example points out that two '<tt>undef</tt>' operands are not
2255 necessarily the same. This can be surprising to people (and also matches C
2256 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2257 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2258 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2259 its value over its "live range". This is true because the variable doesn't
2260 actually <em>have a live range</em>. Instead, the value is logically read
2261 from arbitrary registers that happen to be around when needed, so the value
2262 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2263 need to have the same semantics or the core LLVM "replace all uses with"
2264 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2265
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2266<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2267 %A = fdiv undef, %X
2268 %B = fdiv %X, undef
2269Safe:
2270 %A = undef
2271b: unreachable
2272</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2273
2274<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2275 value</em> and <em>undefined behavior</em>. An undefined value (like
2276 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2277 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2278 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2279 defined on SNaN's. However, in the second example, we can make a more
2280 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2281 arbitrary value, we are allowed to assume that it could be zero. Since a
2282 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2283 the operation does not execute at all. This allows us to delete the divide and
2284 all code after it. Because the undefined operation "can't happen", the
2285 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2286
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2287<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2288a: store undef -> %X
2289b: store %X -> undef
2290Safe:
2291a: &lt;deleted&gt;
2292b: unreachable
2293</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2294
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2295<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2296 undefined value can be assumed to not have any effect; we can assume that the
2297 value is overwritten with bits that happen to match what was already there.
2298 However, a store <em>to</em> an undefined location could clobber arbitrary
2299 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2300
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2301</div>
2302
2303<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2304<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2305<div class="doc_text">
2306
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2307<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2308 instead of representing an unspecified bit pattern, they represent the
2309 fact that an instruction or constant expression which cannot evoke side
2310 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2311 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2312
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2313<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]2314 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2315 <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]2316
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2317<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2318
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2319<ul>
2320<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2321 their operands.</li>
2322
2323<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2324 to their dynamic predecessor basic block.</li>
2325
2326<li>Function arguments depend on the corresponding actual argument values in
2327 the dynamic callers of their functions.</li>
2328
2329<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2330 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2331 control back to them.</li>
2332
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2333<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2334 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2335 or exception-throwing call instructions that dynamically transfer control
2336 back to them.</li>
2337
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2338<li>Non-volatile loads and stores depend on the most recent stores to all of the
2339 referenced memory addresses, following the order in the IR
2340 (including loads and stores implied by intrinsics such as
2341 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2342
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2343<!-- TODO: In the case of multiple threads, this only applies if the store
2344 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2345
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2346<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2347
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2348<li>An instruction with externally visible side effects depends on the most
2349 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2350 the order in the IR. (This includes
2351 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2352
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2353<li>An instruction <i>control-depends</i> on a
2354 <a href="#terminators">terminator instruction</a>
2355 if the terminator instruction has multiple successors and the instruction
2356 is always executed when control transfers to one of the successors, and
2357 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2358
2359<li>Dependence is transitive.</li>
2360
2361</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2362
2363<p>Whenever a trap value is generated, all values which depend on it evaluate
2364 to trap. If they have side effects, the evoke their side effects as if each
2365 operand with a trap value were undef. If they have externally-visible side
2366 effects, the behavior is undefined.</p>
2367
2368<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2369
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2370<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2371entry:
2372 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2373 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2374 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2375 store i32 0, i32* %trap_yet_again ; undefined behavior
2376
2377 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2378 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2379
2380 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2381
2382 %narrowaddr = bitcast i32* @g to i16*
2383 %wideaddr = bitcast i32* @g to i64*
2384 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2385 %trap4 = load i64* %widaddr ; Returns a trap value.
2386
2387 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2388 %br i1 %cmp, %true, %end ; Branch to either destination.
2389
2390true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2391 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2392 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2393 br label %end
2394
2395end:
2396 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2397 ; Both edges into this PHI are
2398 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2399 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2400
2401 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2402 ; so this is defined (ignoring earlier
2403 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2404</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2405
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2406</div>
2407
2408<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2409<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2410 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2411<div class="doc_text">
2412
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2413<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2414
2415<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2416 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2417 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2418
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2419<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2420 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2421 comparisons against null. Pointer equality tests between labels addresses
2422 results in undefined behavior &mdash; though, again, comparison against null
2423 is ok, and no label is equal to the null pointer. This may be passed around
2424 as an opaque pointer sized value as long as the bits are not inspected. This
2425 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2426 long as the original value is reconstituted before the <tt>indirectbr</tt>
2427 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2428
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2429<p>Finally, some targets may provide defined semantics when using the value as
2430 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2431
2432</div>
2433
2434
2435<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2436<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2437</div>
2438
2439<div class="doc_text">
2440
2441<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2442 to be used as constants. Constant expressions may be of
2443 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2444 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2445 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2446
2447<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2448 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2449 <dd>Truncate a constant to another type. The bit size of CST must be larger
2450 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2451
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2452 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2453 <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]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>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 <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]2458 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2459
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2460 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2461 <dd>Truncate a floating point constant to another floating point type. The
2462 size of CST must be larger than the size of TYPE. Both types must be
2463 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2464
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2465 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2466 <dd>Floating point extend a constant to another type. The size of CST must be
2467 smaller or equal to the size of TYPE. Both types must be floating
2468 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2469
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2470 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2471 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2472 constant. TYPE must be a scalar or vector integer type. CST must be of
2473 scalar or vector floating point type. Both CST and TYPE must be scalars,
2474 or vectors of the same number of elements. If the value won't fit in the
2475 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2476
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2477 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2478 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479 constant. TYPE must be a scalar or vector integer type. CST must be of
2480 scalar or vector floating point type. Both CST and TYPE must be scalars,
2481 or vectors of the same number of elements. If the value won't fit in the
2482 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2483
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2484 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2485 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2486 constant. TYPE must be a scalar or vector floating point type. CST must be
2487 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2488 vectors of the same number of elements. If the value won't fit in the
2489 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2490
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2491 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2492 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2493 constant. TYPE must be a scalar or vector floating point type. CST must be
2494 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2495 vectors of the same number of elements. If the value won't fit in the
2496 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2497
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2498 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2499 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2500 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2501 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2502 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2503
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2505 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2506 type. CST must be of integer type. The CST value is zero extended,
2507 truncated, or unchanged to make it fit in a pointer size. This one is
2508 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2509
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2510 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2511 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2512 are the same as those for the <a href="#i_bitcast">bitcast
2513 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2514
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2515 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2516 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2517 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2518 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2519 instruction, the index list may have zero or more indexes, which are
2520 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2521
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2523 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2524
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2526 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2527
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2528 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2529 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on 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>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2533 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2534
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2535 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2537 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2538
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2539 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2540 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2541 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2542
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2543 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2544 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2545 constants. The index list is interpreted in a similar manner as indices in
2546 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2547 index value must be specified.</dd>
2548
2549 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2550 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2551 constants. The index list is interpreted in a similar manner as indices in
2552 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2553 index value must be specified.</dd>
2554
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2555 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2557 be any of the <a href="#binaryops">binary</a>
2558 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2559 on operands are the same as those for the corresponding instruction
2560 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2561</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2562
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2563</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2565<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2566<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2567<!-- *********************************************************************** -->
2568
2569<!-- ======================================================================= -->
2570<div class="doc_subsection">
2571<a name="inlineasm">Inline Assembler Expressions</a>
2572</div>
2573
2574<div class="doc_text">
2575
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2576<p>LLVM supports inline assembler expressions (as opposed
2577 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2578 a special value. This value represents the inline assembler as a string
2579 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2580 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2581 expression has side effects, and a flag indicating whether the function
2582 containing the asm needs to align its stack conservatively. An example
2583 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2584
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2585<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2586i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2587</pre>
2588
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2589<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2590 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2591 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2592
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2593<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2594%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]2595</pre>
2596
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2597<p>Inline asms with side effects not visible in the constraint list must be
2598 marked as having side effects. This is done through the use of the
2599 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2600
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2601<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2602call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2603</pre>
2604
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2605<p>In some cases inline asms will contain code that will not work unless the
2606 stack is aligned in some way, such as calls or SSE instructions on x86,
2607 yet will not contain code that does that alignment within the asm.
2608 The compiler should make conservative assumptions about what the asm might
2609 contain and should generate its usual stack alignment code in the prologue
2610 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2611
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2612<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2613call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2614</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2615
2616<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2617 first.</p>
2618
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2619<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2620 documented here. Constraints on what can be done (e.g. duplication, moving,
2621 etc need to be documented). This is probably best done by reference to
2622 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2623</div>
2624
2625<div class="doc_subsubsection">
2626<a name="inlineasm_md">Inline Asm Metadata</a>
2627</div>
2628
2629<div class="doc_text">
2630
2631<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2632 attached to it that contains a list of constant integers. If present, the
2633 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2634 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2635 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2636 source code that produced it. For example:</p>
2637
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2638<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2639call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2640...
2641!42 = !{ i32 1234567 }
2642</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2643
2644<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]2645 IR. If the MDNode contains multiple constants, the code generator will use
2646 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]2647
2648</div>
2649
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2650<!-- ======================================================================= -->
2651<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2652 Strings</a>
2653</div>
2654
2655<div class="doc_text">
2656
2657<p>LLVM IR allows metadata to be attached to instructions in the program that
2658 can convey extra information about the code to the optimizers and code
2659 generator. One example application of metadata is source-level debug
2660 information. There are two metadata primitives: strings and nodes. All
2661 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2662 preceding exclamation point ('<tt>!</tt>').</p>
2663
2664<p>A metadata string is a string surrounded by double quotes. It can contain
2665 any character by escaping non-printable characters with "\xx" where "xx" is
2666 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2667
2668<p>Metadata nodes are represented with notation similar to structure constants
2669 (a comma separated list of elements, surrounded by braces and preceded by an
2670 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2671 10}</tt>". Metadata nodes can have any values as their operand.</p>
2672
2673<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2674 metadata nodes, which can be looked up in the module symbol table. For
2675 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2676
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2677<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2678 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2679
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2680 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2681 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2682 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2683
2684<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2685 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2686
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2687 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2688 %indvar.next = add i64 %indvar, 1, !dbg !21
2689 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2690</div>
2691
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2692
2693<!-- *********************************************************************** -->
2694<div class="doc_section">
2695 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2696</div>
2697<!-- *********************************************************************** -->
2698
2699<p>LLVM has a number of "magic" global variables that contain data that affect
2700code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2701of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2702section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2703by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2704
2705<!-- ======================================================================= -->
2706<div class="doc_subsection">
2707<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2708</div>
2709
2710<div class="doc_text">
2711
2712<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2713href="#linkage_appending">appending linkage</a>. This array contains a list of
2714pointers to global variables and functions which may optionally have a pointer
2715cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2716
2717<pre>
2718 @X = global i8 4
2719 @Y = global i32 123
2720
2721 @llvm.used = appending global [2 x i8*] [
2722 i8* @X,
2723 i8* bitcast (i32* @Y to i8*)
2724 ], section "llvm.metadata"
2725</pre>
2726
2727<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2728compiler, assembler, and linker are required to treat the symbol as if there is
2729a reference to the global that it cannot see. For example, if a variable has
2730internal linkage and no references other than that from the <tt>@llvm.used</tt>
2731list, it cannot be deleted. This is commonly used to represent references from
2732inline asms and other things the compiler cannot "see", and corresponds to
2733"attribute((used))" in GNU C.</p>
2734
2735<p>On some targets, the code generator must emit a directive to the assembler or
2736object file to prevent the assembler and linker from molesting the symbol.</p>
2737
2738</div>
2739
2740<!-- ======================================================================= -->
2741<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2742<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2743</div>
2744
2745<div class="doc_text">
2746
2747<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2748<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2749touching the symbol. On targets that support it, this allows an intelligent
2750linker to optimize references to the symbol without being impeded as it would be
2751by <tt>@llvm.used</tt>.</p>
2752
2753<p>This is a rare construct that should only be used in rare circumstances, and
2754should not be exposed to source languages.</p>
2755
2756</div>
2757
2758<!-- ======================================================================= -->
2759<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2760<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2761</div>
2762
2763<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2764<pre>
2765%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2766@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2767</pre>
2768<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.
2769</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2770
2771</div>
2772
2773<!-- ======================================================================= -->
2774<div class="doc_subsection">
2775<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2776</div>
2777
2778<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2779<pre>
2780%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2781@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2782</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2783
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2784<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.
2785</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2786
2787</div>
2788
2789
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2790<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2791<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2792<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2794<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2795
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2796<p>The LLVM instruction set consists of several different classifications of
2797 instructions: <a href="#terminators">terminator
2798 instructions</a>, <a href="#binaryops">binary instructions</a>,
2799 <a href="#bitwiseops">bitwise binary instructions</a>,
2800 <a href="#memoryops">memory instructions</a>, and
2801 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2802
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2803</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2805<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2806<div class="doc_subsection"> <a name="terminators">Terminator
2807Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2808
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2809<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2810
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2812 in a program ends with a "Terminator" instruction, which indicates which
2813 block should be executed after the current block is finished. These
2814 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2815 control flow, not values (the one exception being the
2816 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2817
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2818<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2820 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2821 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2822 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2823 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2824 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2825 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2827</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2829<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2830<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2831Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2833<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2835<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2836<pre>
2837 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]2838 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2842<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2843 a value) from a function back to the caller.</p>
2844
2845<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2846 value and then causes control flow, and one that just causes control flow to
2847 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2849<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2850<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2851 return value. The type of the return value must be a
2852 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2855 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2856 value or a return value with a type that does not match its type, or if it
2857 has a void return type and contains a '<tt>ret</tt>' instruction with a
2858 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2860<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2861<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2862 the calling function's context. If the caller is a
2863 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2864 instruction after the call. If the caller was an
2865 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2866 the beginning of the "normal" destination block. If the instruction returns
2867 a value, that value shall set the call or invoke instruction's return
2868 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2869
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2870<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2871<pre>
2872 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2873 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2874 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]2875</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2876
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2877</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2879<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2881<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2884<pre>
2885 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]2886</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2889<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2890 different basic block in the current function. There are two forms of this
2891 instruction, corresponding to a conditional branch and an unconditional
2892 branch.</p>
2893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2894<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2896 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2897 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2898 target.</p>
2899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2900<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2901<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2903 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2904 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2906<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2907<pre>
2908Test:
2909 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2910 br i1 %cond, label %IfEqual, label %IfUnequal
2911IfEqual:
2912 <a href="#i_ret">ret</a> i32 1
2913IfUnequal:
2914 <a href="#i_ret">ret</a> i32 0
2915</pre>
2916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2917</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2919<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2920<div class="doc_subsubsection">
2921 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2922</div>
2923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2924<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2926<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2927<pre>
2928 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2929</pre>
2930
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2931<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2932<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]2933 several different places. It is a generalization of the '<tt>br</tt>'
2934 instruction, allowing a branch to occur to one of many possible
2935 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2937<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2938<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2939 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2940 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2941 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2942
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2943<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2944<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2945 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2946 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2947 transferred to the corresponding destination; otherwise, control flow is
2948 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2949
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2950<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952 <tt>switch</tt> instruction, this instruction may be code generated in
2953 different ways. For example, it could be generated as a series of chained
2954 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2955
2956<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2957<pre>
2958 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2959 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2960 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2961
2962 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2963 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2964
2965 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2966 switch i32 %val, label %otherwise [ i32 0, label %onzero
2967 i32 1, label %onone
2968 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2969</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2971</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2972
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2973
2974<!-- _______________________________________________________________________ -->
2975<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2976 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2977</div>
2978
2979<div class="doc_text">
2980
2981<h5>Syntax:</h5>
2982<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2983 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]2984</pre>
2985
2986<h5>Overview:</h5>
2987
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2988<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2989 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2990 "<tt>address</tt>". Address must be derived from a <a
2991 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2992
2993<h5>Arguments:</h5>
2994
2995<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2996 rest of the arguments indicate the full set of possible destinations that the
2997 address may point to. Blocks are allowed to occur multiple times in the
2998 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2999
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3000<p>This destination list is required so that dataflow analysis has an accurate
3001 understanding of the CFG.</p>
3002
3003<h5>Semantics:</h5>
3004
3005<p>Control transfers to the block specified in the address argument. All
3006 possible destination blocks must be listed in the label list, otherwise this
3007 instruction has undefined behavior. This implies that jumps to labels
3008 defined in other functions have undefined behavior as well.</p>
3009
3010<h5>Implementation:</h5>
3011
3012<p>This is typically implemented with a jump through a register.</p>
3013
3014<h5>Example:</h5>
3015<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3016 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3017</pre>
3018
3019</div>
3020
3021
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3022<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3023<div class="doc_subsubsection">
3024 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3025</div>
3026
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3027<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3028
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3029<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3030<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3031 &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]3032 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3033</pre>
3034
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3035<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3036<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3037 function, with the possibility of control flow transfer to either the
3038 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3039 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3040 control flow will return to the "normal" label. If the callee (or any
3041 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3042 instruction, control is interrupted and continued at the dynamically nearest
3043 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3045<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3046<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3047
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3048<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3049 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3050 convention</a> the call should use. If none is specified, the call
3051 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3052
3053 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3054 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3055 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3056
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3057 <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]3058 function value being invoked. In most cases, this is a direct function
3059 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3060 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3061
3062 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3064
3065 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3066 signature argument types and parameter attributes. All arguments must be
3067 of <a href="#t_firstclass">first class</a> type. If the function
3068 signature indicates the function accepts a variable number of arguments,
3069 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070
3071 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3072 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073
3074 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3076
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3077 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3078 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3079 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3080</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3081
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3082<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083<p>This instruction is designed to operate as a standard
3084 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3085 primary difference is that it establishes an association with a label, which
3086 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3087
3088<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3090 exception. Additionally, this is important for implementation of
3091 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3092
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3093<p>For the purposes of the SSA form, the definition of the value returned by the
3094 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3095 block to the "normal" label. If the callee unwinds then no return value is
3096 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3097
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3098<p>Note that the code generator does not yet completely support unwind, and
3099that the invoke/unwind semantics are likely to change in future versions.</p>
3100
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3101<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3102<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3103 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3104 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3105 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3106 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3107</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3108
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3110
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3111<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3112
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3113<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3114Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3115
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3116<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3117
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3118<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3119<pre>
3120 unwind
3121</pre>
3122
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3123<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3124<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3125 at the first callee in the dynamic call stack which used
3126 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3127 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3128
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3129<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3130<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131 immediately halt. The dynamic call stack is then searched for the
3132 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3133 Once found, execution continues at the "exceptional" destination block
3134 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3135 instruction in the dynamic call chain, undefined behavior results.</p>
3136
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3137<p>Note that the code generator does not yet completely support unwind, and
3138that the invoke/unwind semantics are likely to change in future versions.</p>
3139
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3140</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3141
3142<!-- _______________________________________________________________________ -->
3143
3144<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3145Instruction</a> </div>
3146
3147<div class="doc_text">
3148
3149<h5>Syntax:</h5>
3150<pre>
3151 unreachable
3152</pre>
3153
3154<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3155<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156 instruction is used to inform the optimizer that a particular portion of the
3157 code is not reachable. This can be used to indicate that the code after a
3158 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3159
3160<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3161<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3162
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3163</div>
3164
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3165<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3166<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169
3170<p>Binary operators are used to do most of the computation in a program. They
3171 require two operands of the same type, execute an operation on them, and
3172 produce a single value. The operands might represent multiple data, as is
3173 the case with the <a href="#t_vector">vector</a> data type. The result value
3174 has the same type as its operands.</p>
3175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3176<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3178</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3179
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3180<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3181<div class="doc_subsubsection">
3182 <a name="i_add">'<tt>add</tt>' Instruction</a>
3183</div>
3184
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3185<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3187<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3188<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3189 &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]3190 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3191 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3192 &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]3193</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3194
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3195<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3196<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3198<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199<p>The two arguments to the '<tt>add</tt>' instruction must
3200 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3201 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3203<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3204<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3205
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3206<p>If the sum has unsigned overflow, the result returned is the mathematical
3207 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]3208
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209<p>Because LLVM integers use a two's complement representation, this instruction
3210 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3211
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3212<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3213 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3214 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3215 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3216 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3217
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3218<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3219<pre>
3220 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3223</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3225<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3226<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3227 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3228</div>
3229
3230<div class="doc_text">
3231
3232<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3233<pre>
3234 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3235</pre>
3236
3237<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3238<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3239
3240<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3241<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3243 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3244
3245<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3246<p>The value produced is the floating point sum of the two operands.</p>
3247
3248<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3249<pre>
3250 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3251</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3253</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3255<!-- _______________________________________________________________________ -->
3256<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3257 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3258</div>
3259
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3260<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3262<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3263<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3264 &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]3265 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3266 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3267 &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]3268</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3269
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3270<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3271<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3273
3274<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3275 '<tt>neg</tt>' instruction present in most other intermediate
3276 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3278<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279<p>The two arguments to the '<tt>sub</tt>' instruction must
3280 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3281 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3283<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3284<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3285
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3286<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3287 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3288 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3290<p>Because LLVM integers use a two's complement representation, this instruction
3291 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3292
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3293<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3294 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3295 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3296 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3297 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3298
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3299<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3300<pre>
3301 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3302 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3303</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3304
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3305</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3307<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3308<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3309 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3310</div>
3311
3312<div class="doc_text">
3313
3314<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3315<pre>
3316 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3317</pre>
3318
3319<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3320<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3322
3323<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324 '<tt>fneg</tt>' instruction present in most other intermediate
3325 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3326
3327<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3328<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3329 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3330 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3331
3332<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3333<p>The value produced is the floating point difference of the two operands.</p>
3334
3335<h5>Example:</h5>
3336<pre>
3337 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3338 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3339</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3340
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3341</div>
3342
3343<!-- _______________________________________________________________________ -->
3344<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3345 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3346</div>
3347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3348<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3349
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3350<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3351<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3352 &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]3353 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3354 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3355 &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]3356</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3358<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3361<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3362<p>The two arguments to the '<tt>mul</tt>' instruction must
3363 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3364 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3366<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3367<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3369<p>If the result of the multiplication has unsigned overflow, the result
3370 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3371 width of the result.</p>
3372
3373<p>Because LLVM integers use a two's complement representation, and the result
3374 is the same width as the operands, this instruction returns the correct
3375 result for both signed and unsigned integers. If a full product
3376 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3377 be sign-extended or zero-extended as appropriate to the width of the full
3378 product.</p>
3379
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3380<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3381 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3382 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3383 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3384 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3385
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3386<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3387<pre>
3388 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3389</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3391</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3392
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3393<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3394<div class="doc_subsubsection">
3395 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3396</div>
3397
3398<div class="doc_text">
3399
3400<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3401<pre>
3402 &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]3403</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3404
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3405<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3406<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407
3408<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3409<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3411 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3412
3413<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3414<p>The value produced is the floating point product of the two operands.</p>
3415
3416<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417<pre>
3418 &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]3419</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3421</div>
3422
3423<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3424<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3425</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3427<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3429<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &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]3432</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3434<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3435<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3436
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3437<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3438<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3440 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3441
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3442<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3443<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3445<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3447
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3448<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451<pre>
3452 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3457<!-- _______________________________________________________________________ -->
3458<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3459</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3461<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3464<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3465 &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]3466 &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]3467</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3468
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3471
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3472<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3473<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3475 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3476
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3477<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478<p>The value produced is the signed integer quotient of the two operands rounded
3479 towards zero.</p>
3480
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3481<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3483
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3484<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3485 undefined behavior; this is a rare case, but can occur, for example, by doing
3486 a 32-bit division of -2147483648 by -1.</p>
3487
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3488<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3489 <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]3490 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3491
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3492<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3493<pre>
3494 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3497</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3499<!-- _______________________________________________________________________ -->
3500<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3501Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3503<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3505<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3506<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3507 &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]3508</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3509
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3510<h5>Overview:</h5>
3511<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3512
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3513<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3514<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3515 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3516 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3517
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3518<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3519<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3521<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522<pre>
3523 &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]3524</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3526</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3527
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3528<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3529<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3530</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3532<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3534<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535<pre>
3536 &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]3537</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3539<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3540<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3541 division of its two arguments.</p>
3542
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3543<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3544<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3546 values. Both arguments must have identical types.</p>
3547
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3548<h5>Semantics:</h5>
3549<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550 This instruction always performs an unsigned division to get the
3551 remainder.</p>
3552
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3553<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3555
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3556<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3558<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559<pre>
3560 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3561</pre>
3562
3563</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3565<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566<div class="doc_subsubsection">
3567 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3568</div>
3569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3570<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3571
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3572<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3573<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3574 &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]3575</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3576
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3577<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3578<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3579 division of its two operands. This instruction can also take
3580 <a href="#t_vector">vector</a> versions of the values in which case the
3581 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3582
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3584<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3586 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3587
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3588<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3589<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3590 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3591 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3592 a value. For more information about the difference,
3593 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3594 Math Forum</a>. For a table of how this is implemented in various languages,
3595 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3596 Wikipedia: modulo operation</a>.</p>
3597
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3598<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3600
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3601<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602 Overflow also leads to undefined behavior; this is a rare case, but can
3603 occur, for example, by taking the remainder of a 32-bit division of
3604 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3605 lets srem be implemented using instructions that return both the result of
3606 the division and the remainder.)</p>
3607
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3608<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609<pre>
3610 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611</pre>
3612
3613</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3615<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3616<div class="doc_subsubsection">
3617 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3618
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3619<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3620
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3621<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622<pre>
3623 &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]3624</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3626<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3628 its two operands.</p>
3629
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3630<h5>Arguments:</h5>
3631<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3632 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3633 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3634
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3635<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636<p>This instruction returns the <i>remainder</i> of a division. The remainder
3637 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3638
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3639<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3640<pre>
3641 &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]3642</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3644</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3645
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3646<!-- ======================================================================= -->
3647<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3648Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3650<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651
3652<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3653 program. They are generally very efficient instructions and can commonly be
3654 strength reduced from other instructions. They require two operands of the
3655 same type, execute an operation on them, and produce a single value. The
3656 resulting value is the same type as its operands.</p>
3657
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3658</div>
3659
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3660<!-- _______________________________________________________________________ -->
3661<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3662Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3664<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3666<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667<pre>
3668 &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]3669</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3670
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3671<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3672<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3673 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3674
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3675<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3676<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3677 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3678 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3679
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3680<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3682 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3683 is (statically or dynamically) negative or equal to or larger than the number
3684 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3685 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3686 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688<h5>Example:</h5>
3689<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3690 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3691 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3692 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3693 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3694 &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]3695</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3697</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3699<!-- _______________________________________________________________________ -->
3700<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3701Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3703<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3705<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706<pre>
3707 &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]3708</pre>
3709
3710<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3712 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3713
3714<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3715<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3716 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3717 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3718
3719<h5>Semantics:</h5>
3720<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721 significant bits of the result will be filled with zero bits after the shift.
3722 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3723 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3724 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3725 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3726
3727<h5>Example:</h5>
3728<pre>
3729 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3730 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3731 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3732 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3733 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3734 &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]3735</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3737</div>
3738
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3739<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3740<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3741Instruction</a> </div>
3742<div class="doc_text">
3743
3744<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745<pre>
3746 &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]3747</pre>
3748
3749<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3751 operand shifted to the right a specified number of bits with sign
3752 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753
3754<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3755<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3757 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3758
3759<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3760<p>This instruction always performs an arithmetic shift right operation, The
3761 most significant bits of the result will be filled with the sign bit
3762 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3763 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3764 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3765 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3766
3767<h5>Example:</h5>
3768<pre>
3769 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3770 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3771 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3772 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3773 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3774 &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]3775</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3777</div>
3778
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3779<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3780<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3781Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3782
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3783<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3785<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3786<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3787 &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]3788</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3790<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3792 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3794<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3795<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3796 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3797 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3798
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3799<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3800<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3802<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3803 <tbody>
3804 <tr>
3805 <td>In0</td>
3806 <td>In1</td>
3807 <td>Out</td>
3808 </tr>
3809 <tr>
3810 <td>0</td>
3811 <td>0</td>
3812 <td>0</td>
3813 </tr>
3814 <tr>
3815 <td>0</td>
3816 <td>1</td>
3817 <td>0</td>
3818 </tr>
3819 <tr>
3820 <td>1</td>
3821 <td>0</td>
3822 <td>0</td>
3823 </tr>
3824 <tr>
3825 <td>1</td>
3826 <td>1</td>
3827 <td>1</td>
3828 </tr>
3829 </tbody>
3830</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3832<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3833<pre>
3834 &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]3835 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3836 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3837</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3838</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3839<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3840<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3841
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842<div class="doc_text">
3843
3844<h5>Syntax:</h5>
3845<pre>
3846 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3847</pre>
3848
3849<h5>Overview:</h5>
3850<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3851 two operands.</p>
3852
3853<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3854<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3856 values. Both arguments must have identical types.</p>
3857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3859<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3861<table border="1" cellspacing="0" cellpadding="4">
3862 <tbody>
3863 <tr>
3864 <td>In0</td>
3865 <td>In1</td>
3866 <td>Out</td>
3867 </tr>
3868 <tr>
3869 <td>0</td>
3870 <td>0</td>
3871 <td>0</td>
3872 </tr>
3873 <tr>
3874 <td>0</td>
3875 <td>1</td>
3876 <td>1</td>
3877 </tr>
3878 <tr>
3879 <td>1</td>
3880 <td>0</td>
3881 <td>1</td>
3882 </tr>
3883 <tr>
3884 <td>1</td>
3885 <td>1</td>
3886 <td>1</td>
3887 </tr>
3888 </tbody>
3889</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3891<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3892<pre>
3893 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3894 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3895 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3896</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3898</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3900<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3901<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3902Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3904<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907<pre>
3908 &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]3909</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3913 its two operands. The <tt>xor</tt> is used to implement the "one's
3914 complement" operation, which is the "~" operator in C.</p>
3915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3916<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3917<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3919 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3922<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3924<table border="1" cellspacing="0" cellpadding="4">
3925 <tbody>
3926 <tr>
3927 <td>In0</td>
3928 <td>In1</td>
3929 <td>Out</td>
3930 </tr>
3931 <tr>
3932 <td>0</td>
3933 <td>0</td>
3934 <td>0</td>
3935 </tr>
3936 <tr>
3937 <td>0</td>
3938 <td>1</td>
3939 <td>1</td>
3940 </tr>
3941 <tr>
3942 <td>1</td>
3943 <td>0</td>
3944 <td>1</td>
3945 </tr>
3946 <tr>
3947 <td>1</td>
3948 <td>1</td>
3949 <td>0</td>
3950 </tr>
3951 </tbody>
3952</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3954<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955<pre>
3956 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3957 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3958 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3959 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3960</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3962</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3964<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3965<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3966 <a name="vectorops">Vector Operations</a>
3967</div>
3968
3969<div class="doc_text">
3970
3971<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972 target-independent manner. These instructions cover the element-access and
3973 vector-specific operations needed to process vectors effectively. While LLVM
3974 does directly support these vector operations, many sophisticated algorithms
3975 will want to use target-specific intrinsics to take full advantage of a
3976 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3977
3978</div>
3979
3980<!-- _______________________________________________________________________ -->
3981<div class="doc_subsubsection">
3982 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3983</div>
3984
3985<div class="doc_text">
3986
3987<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3988<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3989 &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]3990</pre>
3991
3992<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3993<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3994 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3995
3996
3997<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3999 of <a href="#t_vector">vector</a> type. The second operand is an index
4000 indicating the position from which to extract the element. The index may be
4001 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4002
4003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4004<p>The result is a scalar of the same type as the element type of
4005 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4006 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4007 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4008
4009<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4010<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4011 &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]4012</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4015
4016<!-- _______________________________________________________________________ -->
4017<div class="doc_subsubsection">
4018 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4019</div>
4020
4021<div class="doc_text">
4022
4023<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4024<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4025 &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]4026</pre>
4027
4028<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4029<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4030 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4031
4032<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4034 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4035 whose type must equal the element type of the first operand. The third
4036 operand is an index indicating the position at which to insert the value.
4037 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4038
4039<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4041 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4042 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4043 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4044
4045<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4046<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4047 &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]4048</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4050</div>
4051
4052<!-- _______________________________________________________________________ -->
4053<div class="doc_subsubsection">
4054 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4055</div>
4056
4057<div class="doc_text">
4058
4059<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4060<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4061 &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]4062</pre>
4063
4064<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4066 from two input vectors, returning a vector with the same element type as the
4067 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4068
4069<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4071 with types that match each other. The third argument is a shuffle mask whose
4072 element type is always 'i32'. The result of the instruction is a vector
4073 whose length is the same as the shuffle mask and whose element type is the
4074 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4075
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076<p>The shuffle mask operand is required to be a constant vector with either
4077 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4080<p>The elements of the two input vectors are numbered from left to right across
4081 both of the vectors. The shuffle mask operand specifies, for each element of
4082 the result vector, which element of the two input vectors the result element
4083 gets. The element selector may be undef (meaning "don't care") and the
4084 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4085
4086<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4087<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4088 &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]4089 &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]4090 &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]4091 &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]4092 &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]4093 &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]4094 &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]4095 &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]4096</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4097
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4099
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4100<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4101<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4102 <a name="aggregateops">Aggregate Operations</a>
4103</div>
4104
4105<div class="doc_text">
4106
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4107<p>LLVM supports several instructions for working with
4108 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4109
4110</div>
4111
4112<!-- _______________________________________________________________________ -->
4113<div class="doc_subsubsection">
4114 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4115</div>
4116
4117<div class="doc_text">
4118
4119<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4120<pre>
4121 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4122</pre>
4123
4124<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4125<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4126 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4127
4128<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4130 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4131 <a href="#t_array">array</a> type. The operands are constant indices to
4132 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4134
4135<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4136<p>The result is the value at the position in the aggregate specified by the
4137 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4138
4139<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4140<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4141 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4142</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4144</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4145
4146<!-- _______________________________________________________________________ -->
4147<div class="doc_subsubsection">
4148 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4149</div>
4150
4151<div class="doc_text">
4152
4153<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4154<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4155 &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]4156</pre>
4157
4158<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4159<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4160 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161
4162<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4164 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4165 <a href="#t_array">array</a> type. The second operand is a first-class
4166 value to insert. The following operands are constant indices indicating
4167 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]4168 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4169 value to insert must have the same type as the value identified by the
4170 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171
4172<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4173<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4174 that of <tt>val</tt> except that the value at the position specified by the
4175 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4176
4177<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4178<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4179 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4180 %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]4181</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4183</div>
4184
4185
4186<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4187<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4188 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4189</div>
4190
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4191<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4192
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4193<p>A key design point of an SSA-based representation is how it represents
4194 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4195 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4196 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4198</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4200<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4201<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4202 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4203</div>
4204
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4205<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4206
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4207<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4208<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4209 &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]4210</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4212<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4213<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214 currently executing function, to be automatically released when this function
4215 returns to its caller. The object is always allocated in the generic address
4216 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4217
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4218<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219<p>The '<tt>alloca</tt>' instruction
4220 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4221 runtime stack, returning a pointer of the appropriate type to the program.
4222 If "NumElements" is specified, it is the number of elements allocated,
4223 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4224 specified, the value result of the allocation is guaranteed to be aligned to
4225 at least that boundary. If not specified, or if zero, the target can choose
4226 to align the allocation on any convenient boundary compatible with the
4227 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4228
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4229<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4230
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4231<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4232<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4233 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4234 memory is automatically released when the function returns. The
4235 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4236 variables that must have an address available. When the function returns
4237 (either with the <tt><a href="#i_ret">ret</a></tt>
4238 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4239 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4242<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4243 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4244 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4245 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4246 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4247</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4249</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4250
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4251<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4252<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4253Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4255<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4257<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4258<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4259 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4260 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4261 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4262</pre>
4263
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4264<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4265<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4267<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4269 from which to load. The pointer must point to
4270 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4271 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4272 number or order of execution of this <tt>load</tt> with other <a
4273 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4275<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4276 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]4277 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278 alignment for the target. It is the responsibility of the code emitter to
4279 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4280 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4281 produce less efficient code. An alignment of 1 is always safe.</p>
4282
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4283<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4284 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4285 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4286 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4287 and code generator that this load is not expected to be reused in the cache.
4288 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4289 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4290
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4291<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292<p>The location of memory pointed to is loaded. If the value being loaded is of
4293 scalar type then the number of bytes read does not exceed the minimum number
4294 of bytes needed to hold all bits of the type. For example, loading an
4295 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4296 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4297 is undefined if the value was not originally written using a store of the
4298 same type.</p>
4299
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4300<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4301<pre>
4302 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4303 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4304 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4305</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4307</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4309<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4310<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4311Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4313<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4315<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4317 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>
4318 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]4319</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4321<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4322<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4324<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4326 and an address at which to store it. The type of the
4327 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4328 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4329 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4330 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4331 order of execution of this <tt>store</tt> with other <a
4332 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333
4334<p>The optional constant "align" argument specifies the alignment of the
4335 operation (that is, the alignment of the memory address). A value of 0 or an
4336 omitted "align" argument means that the operation has the preferential
4337 alignment for the target. It is the responsibility of the code emitter to
4338 ensure that the alignment information is correct. Overestimating the
4339 alignment results in an undefined behavior. Underestimating the alignment may
4340 produce less efficient code. An alignment of 1 is always safe.</p>
4341
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4342<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4343 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4344 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4345 instruction tells the optimizer and code generator that this load is
4346 not expected to be reused in the cache. The code generator may
4347 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4348 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4349
4350
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4351<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4353 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4354 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4355 does not exceed the minimum number of bytes needed to hold all bits of the
4356 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4357 writing a value of a type like <tt>i20</tt> with a size that is not an
4358 integral number of bytes, it is unspecified what happens to the extra bits
4359 that do not belong to the type, but they will typically be overwritten.</p>
4360
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4361<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362<pre>
4363 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4364 store i32 3, i32* %ptr <i>; yields {void}</i>
4365 %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]4366</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4368</div>
4369
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4370<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4371<div class="doc_subsubsection">
4372 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4373</div>
4374
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4375<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4376
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4377<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4378<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4379 &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]4380 &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]4381</pre>
4382
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4383<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4384<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4385 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4386 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4387
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4388<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4389<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4390 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391 elements of the aggregate object are indexed. The interpretation of each
4392 index is dependent on the type being indexed into. The first index always
4393 indexes the pointer value given as the first argument, the second index
4394 indexes a value of the type pointed to (not necessarily the value directly
4395 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4396 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4397 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4398 can never be pointers, since that would require loading the pointer before
4399 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4400
4401<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]4402 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4403 integer <b>constants</b> are allowed. When indexing into an array, pointer
4404 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]4405 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4406
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4407<p>For example, let's consider a C code fragment and how it gets compiled to
4408 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4409
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4410<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4411struct RT {
4412 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4413 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4414 char C;
4415};
4416struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4417 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4418 double Y;
4419 struct RT Z;
4420};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4421
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4422int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4423 return &amp;s[1].Z.B[5][13];
4424}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4425</pre>
4426
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4427<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4428
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4429<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4430%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4431%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4432
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4433define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4434entry:
4435 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4436 ret i32* %reg
4437}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4438</pre>
4439
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4441<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]4442 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4443 }</tt>' type, a structure. The second index indexes into the third element
4444 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4445 i8 }</tt>' type, another structure. The third index indexes into the second
4446 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4447 array. The two dimensions of the array are subscripted into, yielding an
4448 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4449 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4450
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451<p>Note that it is perfectly legal to index partially through a structure,
4452 returning a pointer to an inner element. Because of this, the LLVM code for
4453 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4454
4455<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4456 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4457 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4458 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4459 %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]4460 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4461 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4462 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4463 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4464</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4465
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4466<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4467 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4468 base pointer is not an <i>in bounds</i> address of an allocated object,
4469 or if any of the addresses that would be formed by successive addition of
4470 the offsets implied by the indices to the base address with infinitely
4471 precise arithmetic are not an <i>in bounds</i> address of that allocated
4472 object. The <i>in bounds</i> addresses for an allocated object are all
4473 the addresses that point into the object, plus the address one byte past
4474 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4475
4476<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4477 the base address with silently-wrapping two's complement arithmetic, and
4478 the result value of the <tt>getelementptr</tt> may be outside the object
4479 pointed to by the base pointer. The result value may not necessarily be
4480 used to access memory though, even if it happens to point into allocated
4481 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4482 section for more information.</p>
4483
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4484<p>The getelementptr instruction is often confusing. For some more insight into
4485 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4486
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4487<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4488<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4489 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4490 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4491 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4492 %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]4493 <i>; yields i8*:eptr</i>
4494 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4495 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4496 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4497</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4498
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4499</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4501<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4502<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4503</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4504
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4505<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4506
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4507<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4508 which all take a single operand and a type. They perform various bit
4509 conversions on the operand.</p>
4510
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4511</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4512
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4513<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4514<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4515 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4516</div>
4517<div class="doc_text">
4518
4519<h5>Syntax:</h5>
4520<pre>
4521 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4522</pre>
4523
4524<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4526 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4527
4528<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4530 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4531 size and type of the result, which must be
4532 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4533 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4534 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4535
4536<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4538 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4539 source size must be larger than the destination size, <tt>trunc</tt> cannot
4540 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4541
4542<h5>Example:</h5>
4543<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4544 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4545 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4546 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4549</div>
4550
4551<!-- _______________________________________________________________________ -->
4552<div class="doc_subsubsection">
4553 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4554</div>
4555<div class="doc_text">
4556
4557<h5>Syntax:</h5>
4558<pre>
4559 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4560</pre>
4561
4562<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4563<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4565
4566
4567<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4568<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]4569 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4570 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]4571 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4572 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4573
4574<h5>Semantics:</h5>
4575<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]4576 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4577
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4578<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]4579
4580<h5>Example:</h5>
4581<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4582 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4583 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4584</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4586</div>
4587
4588<!-- _______________________________________________________________________ -->
4589<div class="doc_subsubsection">
4590 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4591</div>
4592<div class="doc_text">
4593
4594<h5>Syntax:</h5>
4595<pre>
4596 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4597</pre>
4598
4599<h5>Overview:</h5>
4600<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4601
4602<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4603<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]4604 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4605 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]4606 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4607 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4608
4609<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4610<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4611 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4612 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4613
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4614<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]4615
4616<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4617<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4618 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4619 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4620</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4622</div>
4623
4624<!-- _______________________________________________________________________ -->
4625<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4626 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4627</div>
4628
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4632<pre>
4633 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4634</pre>
4635
4636<h5>Overview:</h5>
4637<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4638 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4639
4640<h5>Arguments:</h5>
4641<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4643 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]4644 <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]4645 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4646
4647<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4648<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4649 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4650 <a href="#t_floating">floating point</a> type. If the value cannot fit
4651 within the destination type, <tt>ty2</tt>, then the results are
4652 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4653
4654<h5>Example:</h5>
4655<pre>
4656 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4657 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4660</div>
4661
4662<!-- _______________________________________________________________________ -->
4663<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4664 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4665</div>
4666<div class="doc_text">
4667
4668<h5>Syntax:</h5>
4669<pre>
4670 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4671</pre>
4672
4673<h5>Overview:</h5>
4674<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]4675 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4676
4677<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4678<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4679 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4680 a <a href="#t_floating">floating point</a> type to cast it to. The source
4681 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4682
4683<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4684<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4685 <a href="#t_floating">floating point</a> type to a larger
4686 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4687 used to make a <i>no-op cast</i> because it always changes bits. Use
4688 <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]4689
4690<h5>Example:</h5>
4691<pre>
4692 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4693 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4694</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4695
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4696</div>
4697
4698<!-- _______________________________________________________________________ -->
4699<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4700 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4701</div>
4702<div class="doc_text">
4703
4704<h5>Syntax:</h5>
4705<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4706 &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]4707</pre>
4708
4709<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4710<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4711 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4712
4713<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4715 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4716 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4717 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4718 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4719
4720<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4721<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4722 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4723 towards zero) unsigned integer value. If the value cannot fit
4724 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4725
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4726<h5>Example:</h5>
4727<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4728 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4729 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4730 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4731</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4733</div>
4734
4735<!-- _______________________________________________________________________ -->
4736<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4737 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4738</div>
4739<div class="doc_text">
4740
4741<h5>Syntax:</h5>
4742<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4743 &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]4744</pre>
4745
4746<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4747<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 <a href="#t_floating">floating point</a> <tt>value</tt> to
4749 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4750
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4751<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4753 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4754 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4755 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4756 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4757
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4758<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4759<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4761 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4762 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4763
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4764<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4765<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4766 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4767 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4768 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4769</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4770
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4771</div>
4772
4773<!-- _______________________________________________________________________ -->
4774<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4775 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4776</div>
4777<div class="doc_text">
4778
4779<h5>Syntax:</h5>
4780<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4781 &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]4782</pre>
4783
4784<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4785<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4787
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4788<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4789<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]4790 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4791 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4792 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4793 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4794
4795<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4796<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4797 integer quantity and converts it to the corresponding floating point
4798 value. If the value cannot fit in the floating point value, the results are
4799 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4801<h5>Example:</h5>
4802<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4803 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4804 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4805</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4806
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807</div>
4808
4809<!-- _______________________________________________________________________ -->
4810<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4811 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4812</div>
4813<div class="doc_text">
4814
4815<h5>Syntax:</h5>
4816<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4817 &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]4818</pre>
4819
4820<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4821<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4822 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4823
4824<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4825<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]4826 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4827 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4828 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4829 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4830
4831<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4832<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4833 quantity and converts it to the corresponding floating point value. If the
4834 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4835
4836<h5>Example:</h5>
4837<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4838 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4839 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4840</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4841
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4842</div>
4843
4844<!-- _______________________________________________________________________ -->
4845<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4846 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4847</div>
4848<div class="doc_text">
4849
4850<h5>Syntax:</h5>
4851<pre>
4852 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4853</pre>
4854
4855<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4856<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4857 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4858
4859<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4860<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4861 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4862 <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]4863
4864<h5>Semantics:</h5>
4865<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4866 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4867 truncating or zero extending that value to the size of the integer type. If
4868 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4869 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4870 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4871 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4872
4873<h5>Example:</h5>
4874<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4875 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4876 %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]4877</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4878
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
4883 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4884</div>
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
4888<pre>
4889 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4890</pre>
4891
4892<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4893<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4894 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4895
4896<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4897<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898 value to cast, and a type to cast it to, which must be a
4899 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4900
4901<h5>Semantics:</h5>
4902<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4904 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4905 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4906 than the size of a pointer then a zero extension is done. If they are the
4907 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4908
4909<h5>Example:</h5>
4910<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4911 %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]4912 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4913 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4914</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4915
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4916</div>
4917
4918<!-- _______________________________________________________________________ -->
4919<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4920 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4921</div>
4922<div class="doc_text">
4923
4924<h5>Syntax:</h5>
4925<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4926 &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]4927</pre>
4928
4929<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4930<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4932
4933<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4934<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4935 non-aggregate first class value, and a type to cast it to, which must also be
4936 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4937 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4938 identical. If the source type is a pointer, the destination type must also be
4939 a pointer. This instruction supports bitwise conversion of vectors to
4940 integers and to vectors of other types (as long as they have the same
4941 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4942
4943<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4944<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4946 this conversion. The conversion is done as if the <tt>value</tt> had been
4947 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4948 be converted to other pointer types with this instruction. To convert
4949 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4950 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4951
4952<h5>Example:</h5>
4953<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4954 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4955 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4956 %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]4957</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4958
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4959</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4960
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4961<!-- ======================================================================= -->
4962<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4963
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4964<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965
4966<p>The instructions in this category are the "miscellaneous" instructions, which
4967 defy better classification.</p>
4968
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4969</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4970
4971<!-- _______________________________________________________________________ -->
4972<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4973</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4975<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4977<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4978<pre>
4979 &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]4980</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4983<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4984 boolean values based on comparison of its two integer, integer vector, or
4985 pointer operands.</p>
4986
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4987<h5>Arguments:</h5>
4988<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4989 the condition code indicating the kind of comparison to perform. It is not a
4990 value, just a keyword. The possible condition code are:</p>
4991
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4992<ol>
4993 <li><tt>eq</tt>: equal</li>
4994 <li><tt>ne</tt>: not equal </li>
4995 <li><tt>ugt</tt>: unsigned greater than</li>
4996 <li><tt>uge</tt>: unsigned greater or equal</li>
4997 <li><tt>ult</tt>: unsigned less than</li>
4998 <li><tt>ule</tt>: unsigned less or equal</li>
4999 <li><tt>sgt</tt>: signed greater than</li>
5000 <li><tt>sge</tt>: signed greater or equal</li>
5001 <li><tt>slt</tt>: signed less than</li>
5002 <li><tt>sle</tt>: signed less or equal</li>
5003</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5005<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5007 typed. They must also be identical types.</p>
5008
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5009<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5010<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5011 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5012 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]5013 result, as follows:</p>
5014
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5015<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5016 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
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
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5020 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021 <tt>false</tt> otherwise. No sign interpretation is necessary or
5022 performed.</li>
5023
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5024 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5027 <li><tt>uge</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 greater than or equal
5029 to <tt>op2</tt>.</li>
5030
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5031 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5032 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5033
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5034 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5035 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5036
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5037 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5039
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>sge</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 greater than or equal
5042 to <tt>op2</tt>.</li>
5043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5044 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5046
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5047 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048 <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]5049</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5050
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5051<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052 values are compared as if they were integers.</p>
5053
5054<p>If the operands are integer vectors, then they are compared element by
5055 element. The result is an <tt>i1</tt> vector with the same number of elements
5056 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5057
5058<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059<pre>
5060 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5061 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5062 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5063 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5064 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5065 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5066</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5067
5068<p>Note that the code generator does not yet support vector types with
5069 the <tt>icmp</tt> instruction.</p>
5070
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5071</div>
5072
5073<!-- _______________________________________________________________________ -->
5074<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5075</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5077<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5079<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<pre>
5081 &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]5082</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5083
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5084<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5085<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5086 values based on comparison of its operands.</p>
5087
5088<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]5089(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5090
5091<p>If the operands are floating point vectors, then the result type is a vector
5092 of boolean with the same number of elements as the operands being
5093 compared.</p>
5094
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5095<h5>Arguments:</h5>
5096<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097 the condition code indicating the kind of comparison to perform. It is not a
5098 value, just a keyword. The possible condition code are:</p>
5099
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5100<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5101 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5102 <li><tt>oeq</tt>: ordered and equal</li>
5103 <li><tt>ogt</tt>: ordered and greater than </li>
5104 <li><tt>oge</tt>: ordered and greater than or equal</li>
5105 <li><tt>olt</tt>: ordered and less than </li>
5106 <li><tt>ole</tt>: ordered and less than or equal</li>
5107 <li><tt>one</tt>: ordered and not equal</li>
5108 <li><tt>ord</tt>: ordered (no nans)</li>
5109 <li><tt>ueq</tt>: unordered or equal</li>
5110 <li><tt>ugt</tt>: unordered or greater than </li>
5111 <li><tt>uge</tt>: unordered or greater than or equal</li>
5112 <li><tt>ult</tt>: unordered or less than </li>
5113 <li><tt>ule</tt>: unordered or less than or equal</li>
5114 <li><tt>une</tt>: unordered or not equal</li>
5115 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5116 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5117</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5118
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5119<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5120 <i>unordered</i> means that either operand may be a QNAN.</p>
5121
5122<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5123 a <a href="#t_floating">floating point</a> type or
5124 a <a href="#t_vector">vector</a> of floating point type. They must have
5125 identical types.</p>
5126
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5127<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5128<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5129 according to the condition code given as <tt>cond</tt>. If the operands are
5130 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5131 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5132 follows:</p>
5133
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5134<ol>
5135 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5137 <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]5138 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5139
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5140 <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]5141 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5142
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5143 <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]5144 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5145
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5146 <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]5147 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5148
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5149 <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]5150 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5151
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5152 <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]5153 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5154
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5155 <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]5156
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5157 <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]5158 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5159
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5160 <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]5161 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5162
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5163 <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]5164 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5165
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5166 <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]5167 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5168
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5169 <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]5170 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5171
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5172 <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]5173 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5174
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5175 <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]5176
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5177 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5178</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5179
5180<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5181<pre>
5182 &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]5183 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5184 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5185 &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]5186</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5187
5188<p>Note that the code generator does not yet support vector types with
5189 the <tt>fcmp</tt> instruction.</p>
5190
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5191</div>
5192
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5193<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5194<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5195 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5196</div>
5197
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5198<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5199
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5200<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5201<pre>
5202 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5203</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5204
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5206<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5207 SSA graph representing the function.</p>
5208
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5210<p>The type of the incoming values is specified with the first type field. After
5211 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5212 one pair for each predecessor basic block of the current block. Only values
5213 of <a href="#t_firstclass">first class</a> type may be used as the value
5214 arguments to the PHI node. Only labels may be used as the label
5215 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5216
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217<p>There must be no non-phi instructions between the start of a basic block and
5218 the PHI instructions: i.e. PHI instructions must be first in a basic
5219 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5220
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5221<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5222 occur on the edge from the corresponding predecessor block to the current
5223 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5224 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5225
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5227<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5228 specified by the pair corresponding to the predecessor basic block that
5229 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5231<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5232<pre>
5233Loop: ; Infinite loop that counts from 0 on up...
5234 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5235 %nextindvar = add i32 %indvar, 1
5236 br label %Loop
5237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5238
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5239</div>
5240
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5241<!-- _______________________________________________________________________ -->
5242<div class="doc_subsubsection">
5243 <a name="i_select">'<tt>select</tt>' Instruction</a>
5244</div>
5245
5246<div class="doc_text">
5247
5248<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5249<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5250 &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>
5251
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5252 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5253</pre>
5254
5255<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5256<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5257 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5258
5259
5260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5261<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5262 values indicating the condition, and two values of the
5263 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5264 vectors and the condition is a scalar, then entire vectors are selected, not
5265 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5266
5267<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5269 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5270
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5271<p>If the condition is a vector of i1, then the value arguments must be vectors
5272 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5273
5274<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5275<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5276 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5277</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5278
5279<p>Note that the code generator does not yet support conditions
5280 with vector type.</p>
5281
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5282</div>
5283
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5284<!-- _______________________________________________________________________ -->
5285<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5286 <a name="i_call">'<tt>call</tt>' Instruction</a>
5287</div>
5288
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5289<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5291<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5292<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5293 &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]5294</pre>
5295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5296<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5297<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5298
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5299<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5300<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5301
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5302<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5303 <li>The optional "tail" marker indicates that the callee function does not
5304 access any allocas or varargs in the caller. Note that calls may be
5305 marked "tail" even if they do not occur before
5306 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5307 present, the function call is eligible for tail call optimization,
5308 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5309 optimized into a jump</a>. The code generator may optimize calls marked
5310 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5311 sibling call optimization</a> when the caller and callee have
5312 matching signatures, or 2) forced tail call optimization when the
5313 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5314 <ul>
5315 <li>Caller and callee both have the calling
5316 convention <tt>fastcc</tt>.</li>
5317 <li>The call is in tail position (ret immediately follows call and ret
5318 uses value of call or is void).</li>
5319 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5320 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5321 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5322 constraints are met.</a></li>
5323 </ul>
5324 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5326 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5327 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5328 defaults to using C calling conventions. The calling convention of the
5329 call must match the calling convention of the target function, or else the
5330 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5331
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5332 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5333 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5334 '<tt>inreg</tt>' attributes are valid here.</li>
5335
5336 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5337 type of the return value. Functions that return no value are marked
5338 <tt><a href="#t_void">void</a></tt>.</li>
5339
5340 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5341 being invoked. The argument types must match the types implied by this
5342 signature. This type can be omitted if the function is not varargs and if
5343 the function type does not return a pointer to a function.</li>
5344
5345 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5346 be invoked. In most cases, this is a direct function invocation, but
5347 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5348 to function value.</li>
5349
5350 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5351 signature argument types and parameter attributes. All arguments must be
5352 of <a href="#t_firstclass">first class</a> type. If the function
5353 signature indicates the function accepts a variable number of arguments,
5354 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355
5356 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5357 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5358 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5359</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5361<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5362<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5363 a specified function, with its incoming arguments bound to the specified
5364 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5365 function, control flow continues with the instruction after the function
5366 call, and the return value of the function is bound to the result
5367 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5368
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5369<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5370<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5371 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5372 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5373 %X = tail call i32 @foo() <i>; yields i32</i>
5374 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5375 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5376
5377 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5378 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5379 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5380 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5381 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5382 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5383</pre>
5384
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5385<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5386standard C99 library as being the C99 library functions, and may perform
5387optimizations or generate code for them under that assumption. This is
5388something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5389freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5391</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5392
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5393<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5394<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5395 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5396</div>
5397
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5398<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5399
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5400<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5401<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5402 &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]5403</pre>
5404
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5405<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5406<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5407 the "variable argument" area of a function call. It is used to implement the
5408 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5409
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5410<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5411<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5412 argument. It returns a value of the specified argument type and increments
5413 the <tt>va_list</tt> to point to the next argument. The actual type
5414 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5415
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5416<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5417<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5418 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5419 to the next argument. For more information, see the variable argument
5420 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5421
5422<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]5423 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5424 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5425
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5426<p><tt>va_arg</tt> is an LLVM instruction instead of
5427 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5428 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5429
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5430<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5431<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5432
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5433<p>Note that the code generator does not yet fully support va_arg on many
5434 targets. Also, it does not currently support va_arg with aggregate types on
5435 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5437</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5438
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5439<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5440<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5441<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5443<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5444
5445<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446 well known names and semantics and are required to follow certain
5447 restrictions. Overall, these intrinsics represent an extension mechanism for
5448 the LLVM language that does not require changing all of the transformations
5449 in LLVM when adding to the language (or the bitcode reader/writer, the
5450 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5451
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5452<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5453 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5454 begin with this prefix. Intrinsic functions must always be external
5455 functions: you cannot define the body of intrinsic functions. Intrinsic
5456 functions may only be used in call or invoke instructions: it is illegal to
5457 take the address of an intrinsic function. Additionally, because intrinsic
5458 functions are part of the LLVM language, it is required if any are added that
5459 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5460
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5461<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5462 family of functions that perform the same operation but on different data
5463 types. Because LLVM can represent over 8 million different integer types,
5464 overloading is used commonly to allow an intrinsic function to operate on any
5465 integer type. One or more of the argument types or the result type can be
5466 overloaded to accept any integer type. Argument types may also be defined as
5467 exactly matching a previous argument's type or the result type. This allows
5468 an intrinsic function which accepts multiple arguments, but needs all of them
5469 to be of the same type, to only be overloaded with respect to a single
5470 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5471
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472<p>Overloaded intrinsics will have the names of its overloaded argument types
5473 encoded into its function name, each preceded by a period. Only those types
5474 which are overloaded result in a name suffix. Arguments whose type is matched
5475 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5476 can take an integer of any width and returns an integer of exactly the same
5477 integer width. This leads to a family of functions such as
5478 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5479 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5480 suffix is required. Because the argument's type is matched against the return
5481 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5482
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5483<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5484 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5485
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5486</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5487
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5488<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5489<div class="doc_subsection">
5490 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5491</div>
5492
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5493<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5494
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5495<p>Variable argument support is defined in LLVM with
5496 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5497 intrinsic functions. These functions are related to the similarly named
5498 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5499
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>All of these functions operate on arguments that use a target-specific value
5501 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5502 not define what this type is, so all transformations should be prepared to
5503 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5504
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5505<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]5506 instruction and the variable argument handling intrinsic functions are
5507 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5508
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5509<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5510define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5511 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5512 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5513 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5514 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5515
5516 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5517 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5518
5519 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5520 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5521 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5522 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5523 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5524
5525 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5526 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5527 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5528}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5529
5530declare void @llvm.va_start(i8*)
5531declare void @llvm.va_copy(i8*, i8*)
5532declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5533</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5534
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5535</div>
5536
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5537<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5538<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5539 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5540</div>
5541
5542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5543<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5544
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5545<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5546<pre>
5547 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5548</pre>
5549
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5550<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5551<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5552 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]5553
5554<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5555<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]5556
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5557<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5558<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]5559 macro available in C. In a target-dependent way, it initializes
5560 the <tt>va_list</tt> element to which the argument points, so that the next
5561 call to <tt>va_arg</tt> will produce the first variable argument passed to
5562 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5563 need to know the last argument of the function as the compiler can figure
5564 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5565
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5566</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5567
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5568<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5569<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5570 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5571</div>
5572
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5573<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5574
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5575<h5>Syntax:</h5>
5576<pre>
5577 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5578</pre>
5579
5580<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5581<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5582 which has been initialized previously
5583 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5584 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5585
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5586<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5587<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]5588
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5589<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5590<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]5591 macro available in C. In a target-dependent way, it destroys
5592 the <tt>va_list</tt> element to which the argument points. Calls
5593 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5594 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5595 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5596
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5597</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5598
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5599<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5600<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5601 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5602</div>
5603
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5604<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5605
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5606<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5607<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5608 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5609</pre>
5610
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5611<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5612<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5613 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5616<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]5617 The second argument is a pointer to a <tt>va_list</tt> element to copy
5618 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5619
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5620<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5621<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]5622 macro available in C. In a target-dependent way, it copies the
5623 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5624 element. This intrinsic is necessary because
5625 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5626 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5627
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5628</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5629
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5630<!-- ======================================================================= -->
5631<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5632 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5633</div>
5634
5635<div class="doc_text">
5636
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5637<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5638Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5639intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5640roots on the stack</a>, as well as garbage collector implementations that
5641require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5642barriers. Front-ends for type-safe garbage collected languages should generate
5643these intrinsics to make use of the LLVM garbage collectors. For more details,
5644see <a href="GarbageCollection.html">Accurate Garbage Collection with
5645LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5646
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5647<p>The garbage collection intrinsics only operate on objects in the generic
5648 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5649
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5650</div>
5651
5652<!-- _______________________________________________________________________ -->
5653<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5654 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5655</div>
5656
5657<div class="doc_text">
5658
5659<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5660<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5661 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5662</pre>
5663
5664<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5665<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]5666 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5667
5668<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5669<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5670 root pointer. The second pointer (which must be either a constant or a
5671 global value address) contains the meta-data to be associated with the
5672 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5673
5674<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5675<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]5676 location. At compile-time, the code generator generates information to allow
5677 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5678 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5679 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5680
5681</div>
5682
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683<!-- _______________________________________________________________________ -->
5684<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5685 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5686</div>
5687
5688<div class="doc_text">
5689
5690<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5691<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5692 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5693</pre>
5694
5695<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5696<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5697 locations, allowing garbage collector implementations that require read
5698 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5699
5700<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5701<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]5702 allocated from the garbage collector. The first object is a pointer to the
5703 start of the referenced object, if needed by the language runtime (otherwise
5704 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5705
5706<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5708 instruction, but may be replaced with substantially more complex code by the
5709 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5710 may only be used in a function which <a href="#gc">specifies a GC
5711 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712
5713</div>
5714
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715<!-- _______________________________________________________________________ -->
5716<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5717 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718</div>
5719
5720<div class="doc_text">
5721
5722<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5724 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5725</pre>
5726
5727<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5728<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729 locations, allowing garbage collector implementations that require write
5730 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5733<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]5734 object to store it to, and the third is the address of the field of Obj to
5735 store to. If the runtime does not require a pointer to the object, Obj may
5736 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737
5738<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5740 instruction, but may be replaced with substantially more complex code by the
5741 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5742 may only be used in a function which <a href="#gc">specifies a GC
5743 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744
5745</div>
5746
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5747<!-- ======================================================================= -->
5748<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5749 <a name="int_codegen">Code Generator Intrinsics</a>
5750</div>
5751
5752<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5753
5754<p>These intrinsics are provided by LLVM to expose special features that may
5755 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5756
5757</div>
5758
5759<!-- _______________________________________________________________________ -->
5760<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5761 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5762</div>
5763
5764<div class="doc_text">
5765
5766<h5>Syntax:</h5>
5767<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5768 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5769</pre>
5770
5771<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5773 target-specific value indicating the return address of the current function
5774 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775
5776<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777<p>The argument to this intrinsic indicates which function to return the address
5778 for. Zero indicates the calling function, one indicates its caller, etc.
5779 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5780
5781<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5782<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5783 indicating the return address of the specified call frame, or zero if it
5784 cannot be identified. The value returned by this intrinsic is likely to be
5785 incorrect or 0 for arguments other than zero, so it should only be used for
5786 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5788<p>Note that calling this intrinsic does not prevent function inlining or other
5789 aggressive transformations, so the value returned may not be that of the
5790 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5791
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5792</div>
5793
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5794<!-- _______________________________________________________________________ -->
5795<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5796 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797</div>
5798
5799<div class="doc_text">
5800
5801<h5>Syntax:</h5>
5802<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5803 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5804</pre>
5805
5806<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5808 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5809
5810<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The argument to this intrinsic indicates which function to return the frame
5812 pointer for. Zero indicates the calling function, one indicates its caller,
5813 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5814
5815<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5816<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5817 indicating the frame address of the specified call frame, or zero if it
5818 cannot be identified. The value returned by this intrinsic is likely to be
5819 incorrect or 0 for arguments other than zero, so it should only be used for
5820 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5821
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822<p>Note that calling this intrinsic does not prevent function inlining or other
5823 aggressive transformations, so the value returned may not be that of the
5824 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5825
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5826</div>
5827
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5828<!-- _______________________________________________________________________ -->
5829<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5830 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5831</div>
5832
5833<div class="doc_text">
5834
5835<h5>Syntax:</h5>
5836<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5837 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5838</pre>
5839
5840<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5841<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5842 of the function stack, for use
5843 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5844 useful for implementing language features like scoped automatic variable
5845 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5846
5847<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5848<p>This intrinsic returns a opaque pointer value that can be passed
5849 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5850 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5851 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5852 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5853 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5854 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5855
5856</div>
5857
5858<!-- _______________________________________________________________________ -->
5859<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5860 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5861</div>
5862
5863<div class="doc_text">
5864
5865<h5>Syntax:</h5>
5866<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5867 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5868</pre>
5869
5870<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5872 the function stack to the state it was in when the
5873 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5874 executed. This is useful for implementing language features like scoped
5875 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5876
5877<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5878<p>See the description
5879 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5880
5881</div>
5882
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5883<!-- _______________________________________________________________________ -->
5884<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5885 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5886</div>
5887
5888<div class="doc_text">
5889
5890<h5>Syntax:</h5>
5891<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5892 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]5893</pre>
5894
5895<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5897 insert a prefetch instruction if supported; otherwise, it is a noop.
5898 Prefetches have no effect on the behavior of the program but can change its
5899 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5900
5901<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5902<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5903 specifier determining if the fetch should be for a read (0) or write (1),
5904 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5905 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5906 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5907
5908<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5909<p>This intrinsic does not modify the behavior of the program. In particular,
5910 prefetches cannot trap and do not produce a value. On targets that support
5911 this intrinsic, the prefetch can provide hints to the processor cache for
5912 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5913
5914</div>
5915
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5918 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
5924<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5925 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5926</pre>
5927
5928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5930 Counter (PC) in a region of code to simulators and other tools. The method
5931 is target specific, but it is expected that the marker will use exported
5932 symbols to transmit the PC of the marker. The marker makes no guarantees
5933 that it will remain with any specific instruction after optimizations. It is
5934 possible that the presence of a marker will inhibit optimizations. The
5935 intended use is to be inserted after optimizations to allow correlations of
5936 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5937
5938<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5939<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5940
5941<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5943 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5944
5945</div>
5946
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5947<!-- _______________________________________________________________________ -->
5948<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5949 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5950</div>
5951
5952<div class="doc_text">
5953
5954<h5>Syntax:</h5>
5955<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5956 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5957</pre>
5958
5959<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5961 counter register (or similar low latency, high accuracy clocks) on those
5962 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5963 should map to RPCC. As the backing counters overflow quickly (on the order
5964 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5965
5966<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5967<p>When directly supported, reading the cycle counter should not modify any
5968 memory. Implementations are allowed to either return a application specific
5969 value or a system wide value. On backends without support, this is lowered
5970 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5971
5972</div>
5973
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5974<!-- ======================================================================= -->
5975<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5976 <a name="int_libc">Standard C Library Intrinsics</a>
5977</div>
5978
5979<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5980
5981<p>LLVM provides intrinsics for a few important standard C library functions.
5982 These intrinsics allow source-language front-ends to pass information about
5983 the alignment of the pointer arguments to the code generator, providing
5984 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5985
5986</div>
5987
5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5990 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5996<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]5997 integer bit width and for different address spaces. Not all targets support
5998 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5999
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6000<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6001 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]6002 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6003 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]6004 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6005</pre>
6006
6007<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6009 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6012 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6013 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6014
6015<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6017<p>The first argument is a pointer to the destination, the second is a pointer
6018 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6019 number of bytes to copy, the fourth argument is the alignment of the
6020 source and destination locations, and the fifth is a boolean indicating a
6021 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6022
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6023<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]6024 then the caller guarantees that both the source and destination pointers are
6025 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6026
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6027<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6028 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6029 The detailed access behavior is not very cleanly specified and it is unwise
6030 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6031
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6032<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6033
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6034<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6035 source location to the destination location, which are not allowed to
6036 overlap. It copies "len" bytes of memory over. If the argument is known to
6037 be aligned to some boundary, this can be specified as the fourth argument,
6038 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6039
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6040</div>
6041
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6042<!-- _______________________________________________________________________ -->
6043<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6044 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6045</div>
6046
6047<div class="doc_text">
6048
6049<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6050<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]6051 width and for different address space. Not all targets support all bit
6052 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6053
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6054<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6055 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]6056 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6057 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]6058 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6059</pre>
6060
6061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6063 source location to the destination location. It is similar to the
6064 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6065 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6066
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6067<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6068 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6069 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6070
6071<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6073<p>The first argument is a pointer to the destination, the second is a pointer
6074 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6075 number of bytes to copy, the fourth argument is the alignment of the
6076 source and destination locations, and the fifth is a boolean indicating a
6077 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6078
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6079<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]6080 then the caller guarantees that the source and destination pointers are
6081 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6082
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6083<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6084 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6085 The detailed access behavior is not very cleanly specified and it is unwise
6086 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6087
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6088<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6089
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6090<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6091 source location to the destination location, which may overlap. It copies
6092 "len" bytes of memory over. If the argument is known to be aligned to some
6093 boundary, this can be specified as the fourth argument, otherwise it should
6094 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6095
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6096</div>
6097
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6098<!-- _______________________________________________________________________ -->
6099<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6100 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6101</div>
6102
6103<div class="doc_text">
6104
6105<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6106<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]6107 width and for different address spaces. However, not all targets support all
6108 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6109
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6110<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6111 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6112 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6113 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6114 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6115</pre>
6116
6117<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6119 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6120
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6122 intrinsic does not return a value and takes extra alignment/volatile
6123 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6124
6125<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6126<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]6127 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6128 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6129 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6130
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6131<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]6132 then the caller guarantees that the destination pointer is aligned to that
6133 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6134
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6135<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6136 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6137 The detailed access behavior is not very cleanly specified and it is unwise
6138 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6139
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6140<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6141<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6142 at the destination location. If the argument is known to be aligned to some
6143 boundary, this can be specified as the fourth argument, otherwise it should
6144 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6145
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6146</div>
6147
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6148<!-- _______________________________________________________________________ -->
6149<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6150 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6151</div>
6152
6153<div class="doc_text">
6154
6155<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6156<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6157 floating point or vector of floating point type. Not all targets support all
6158 types however.</p>
6159
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6160<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6161 declare float @llvm.sqrt.f32(float %Val)
6162 declare double @llvm.sqrt.f64(double %Val)
6163 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6164 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6165 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6166</pre>
6167
6168<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6169<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6170 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6171 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6172 behavior for negative numbers other than -0.0 (which allows for better
6173 optimization, because there is no need to worry about errno being
6174 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]6175
6176<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6177<p>The argument and return value are floating point numbers of the same
6178 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6179
6180<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181<p>This function returns the sqrt of the specified operand if it is a
6182 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6183
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6184</div>
6185
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6186<!-- _______________________________________________________________________ -->
6187<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6188 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6189</div>
6190
6191<div class="doc_text">
6192
6193<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6194<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6195 floating point or vector of floating point type. Not all targets support all
6196 types however.</p>
6197
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6198<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6199 declare float @llvm.powi.f32(float %Val, i32 %power)
6200 declare double @llvm.powi.f64(double %Val, i32 %power)
6201 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6202 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6203 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6204</pre>
6205
6206<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6207<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6208 specified (positive or negative) power. The order of evaluation of
6209 multiplications is not defined. When a vector of floating point type is
6210 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6211
6212<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6213<p>The second argument is an integer power, and the first is a value to raise to
6214 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6215
6216<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6217<p>This function returns the first value raised to the second power with an
6218 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6219
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6220</div>
6221
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6222<!-- _______________________________________________________________________ -->
6223<div class="doc_subsubsection">
6224 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6225</div>
6226
6227<div class="doc_text">
6228
6229<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6230<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6231 floating point or vector of floating point type. Not all targets support all
6232 types however.</p>
6233
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6234<pre>
6235 declare float @llvm.sin.f32(float %Val)
6236 declare double @llvm.sin.f64(double %Val)
6237 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6238 declare fp128 @llvm.sin.f128(fp128 %Val)
6239 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6240</pre>
6241
6242<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6244
6245<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6246<p>The argument and return value are floating point numbers of the same
6247 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6248
6249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6250<p>This function returns the sine of the specified operand, returning the same
6251 values as the libm <tt>sin</tt> functions would, and handles error conditions
6252 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6253
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6254</div>
6255
6256<!-- _______________________________________________________________________ -->
6257<div class="doc_subsubsection">
6258 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6259</div>
6260
6261<div class="doc_text">
6262
6263<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6264<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6265 floating point or vector of floating point type. Not all targets support all
6266 types however.</p>
6267
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6268<pre>
6269 declare float @llvm.cos.f32(float %Val)
6270 declare double @llvm.cos.f64(double %Val)
6271 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6272 declare fp128 @llvm.cos.f128(fp128 %Val)
6273 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6274</pre>
6275
6276<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6277<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6278
6279<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6280<p>The argument and return value are floating point numbers of the same
6281 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6282
6283<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6284<p>This function returns the cosine of the specified operand, returning the same
6285 values as the libm <tt>cos</tt> functions would, and handles error conditions
6286 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6287
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6288</div>
6289
6290<!-- _______________________________________________________________________ -->
6291<div class="doc_subsubsection">
6292 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6293</div>
6294
6295<div class="doc_text">
6296
6297<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6298<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6299 floating point or vector of floating point type. Not all targets support all
6300 types however.</p>
6301
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6302<pre>
6303 declare float @llvm.pow.f32(float %Val, float %Power)
6304 declare double @llvm.pow.f64(double %Val, double %Power)
6305 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6306 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6307 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6308</pre>
6309
6310<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6311<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6312 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6313
6314<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315<p>The second argument is a floating point power, and the first is a value to
6316 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6317
6318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>This function returns the first value raised to the second power, returning
6320 the same values as the libm <tt>pow</tt> functions would, and handles error
6321 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6322
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6323</div>
6324
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6325<!-- ======================================================================= -->
6326<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6327 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6328</div>
6329
6330<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6331
6332<p>LLVM provides intrinsics for a few important bit manipulation operations.
6333 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6334
6335</div>
6336
6337<!-- _______________________________________________________________________ -->
6338<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6339 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6340</div>
6341
6342<div class="doc_text">
6343
6344<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6345<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6346 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6347
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6348<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6349 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6350 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6351 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6352</pre>
6353
6354<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6355<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6356 values with an even number of bytes (positive multiple of 16 bits). These
6357 are useful for performing operations on data that is not in the target's
6358 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6359
6360<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6361<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6362 and low byte of the input i16 swapped. Similarly,
6363 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6364 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6365 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6366 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6367 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6368 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6369
6370</div>
6371
6372<!-- _______________________________________________________________________ -->
6373<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6374 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6375</div>
6376
6377<div class="doc_text">
6378
6379<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6380<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]6381 width. Not all targets support all bit widths however.</p>
6382
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6383<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6384 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6385 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6386 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6387 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6388 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6389</pre>
6390
6391<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6392<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6393 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6394
6395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396<p>The only argument is the value to be counted. The argument may be of any
6397 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6398
6399<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6400<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]6401
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6402</div>
6403
6404<!-- _______________________________________________________________________ -->
6405<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6406 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6407</div>
6408
6409<div class="doc_text">
6410
6411<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6412<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6413 integer bit width. Not all targets support all bit widths however.</p>
6414
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6415<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6416 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6417 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6418 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6419 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6420 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6425 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6426
6427<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428<p>The only argument is the value to be counted. The argument may be of any
6429 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6430
6431<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6433 zeros in a variable. If the src == 0 then the result is the size in bits of
6434 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6435
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6436</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6437
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6438<!-- _______________________________________________________________________ -->
6439<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6440 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6441</div>
6442
6443<div class="doc_text">
6444
6445<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6446<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6447 integer bit width. Not all targets support all bit widths however.</p>
6448
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6449<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6450 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6451 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6452 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6453 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6454 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6455</pre>
6456
6457<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6459 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6460
6461<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<p>The only argument is the value to be counted. The argument may be of any
6463 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6464
6465<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6467 zeros in a variable. If the src == 0 then the result is the size in bits of
6468 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6469
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6470</div>
6471
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6472<!-- ======================================================================= -->
6473<div class="doc_subsection">
6474 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6475</div>
6476
6477<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6478
6479<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6480
6481</div>
6482
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6483<!-- _______________________________________________________________________ -->
6484<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6485 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6486</div>
6487
6488<div class="doc_text">
6489
6490<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6491<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]6492 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6493
6494<pre>
6495 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6496 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6497 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6498</pre>
6499
6500<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6501<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6502 a signed addition of the two arguments, and indicate whether an overflow
6503 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6504
6505<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6506<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]6507 be of integer types of any bit width, but they must have the same bit
6508 width. The second element of the result structure must be of
6509 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6510 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6511
6512<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6513<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6514 a signed addition of the two variables. They return a structure &mdash; the
6515 first element of which is the signed summation, and the second element of
6516 which is a bit specifying if the signed summation resulted in an
6517 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6518
6519<h5>Examples:</h5>
6520<pre>
6521 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6522 %sum = extractvalue {i32, i1} %res, 0
6523 %obit = extractvalue {i32, i1} %res, 1
6524 br i1 %obit, label %overflow, label %normal
6525</pre>
6526
6527</div>
6528
6529<!-- _______________________________________________________________________ -->
6530<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6531 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532</div>
6533
6534<div class="doc_text">
6535
6536<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6537<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]6538 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6539
6540<pre>
6541 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6542 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6543 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6544</pre>
6545
6546<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6547<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548 an unsigned addition of the two arguments, and indicate whether a carry
6549 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6552<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]6553 be of integer types of any bit width, but they must have the same bit
6554 width. The second element of the result structure must be of
6555 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6556 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6557
6558<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6559<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560 an unsigned addition of the two arguments. They return a structure &mdash;
6561 the first element of which is the sum, and the second element of which is a
6562 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6563
6564<h5>Examples:</h5>
6565<pre>
6566 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6567 %sum = extractvalue {i32, i1} %res, 0
6568 %obit = extractvalue {i32, i1} %res, 1
6569 br i1 %obit, label %carry, label %normal
6570</pre>
6571
6572</div>
6573
6574<!-- _______________________________________________________________________ -->
6575<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6576 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6577</div>
6578
6579<div class="doc_text">
6580
6581<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6582<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]6583 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6584
6585<pre>
6586 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6587 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6588 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6589</pre>
6590
6591<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6592<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6593 a signed subtraction of the two arguments, and indicate whether an overflow
6594 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6595
6596<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6597<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]6598 be of integer types of any bit width, but they must have the same bit
6599 width. The second element of the result structure must be of
6600 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6601 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6602
6603<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6604<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6605 a signed subtraction of the two arguments. They return a structure &mdash;
6606 the first element of which is the subtraction, and the second element of
6607 which is a bit specifying if the signed subtraction resulted in an
6608 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6609
6610<h5>Examples:</h5>
6611<pre>
6612 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6613 %sum = extractvalue {i32, i1} %res, 0
6614 %obit = extractvalue {i32, i1} %res, 1
6615 br i1 %obit, label %overflow, label %normal
6616</pre>
6617
6618</div>
6619
6620<!-- _______________________________________________________________________ -->
6621<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6622 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623</div>
6624
6625<div class="doc_text">
6626
6627<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6628<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]6629 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6630
6631<pre>
6632 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6633 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6634 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6635</pre>
6636
6637<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6638<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6639 an unsigned subtraction of the two arguments, and indicate whether an
6640 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6643<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]6644 be of integer types of any bit width, but they must have the same bit
6645 width. The second element of the result structure must be of
6646 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6647 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6648
6649<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6650<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6651 an unsigned subtraction of the two arguments. They return a structure &mdash;
6652 the first element of which is the subtraction, and the second element of
6653 which is a bit specifying if the unsigned subtraction resulted in an
6654 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6655
6656<h5>Examples:</h5>
6657<pre>
6658 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6659 %sum = extractvalue {i32, i1} %res, 0
6660 %obit = extractvalue {i32, i1} %res, 1
6661 br i1 %obit, label %overflow, label %normal
6662</pre>
6663
6664</div>
6665
6666<!-- _______________________________________________________________________ -->
6667<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6668 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669</div>
6670
6671<div class="doc_text">
6672
6673<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6674<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]6675 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6676
6677<pre>
6678 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6679 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6680 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6681</pre>
6682
6683<h5>Overview:</h5>
6684
6685<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6686 a signed multiplication of the two arguments, and indicate whether an
6687 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6688
6689<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690<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]6691 be of integer types of any bit width, but they must have the same bit
6692 width. The second element of the result structure must be of
6693 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6694 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6695
6696<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6697<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6698 a signed multiplication of the two arguments. They return a structure &mdash;
6699 the first element of which is the multiplication, and the second element of
6700 which is a bit specifying if the signed multiplication resulted in an
6701 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6702
6703<h5>Examples:</h5>
6704<pre>
6705 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6706 %sum = extractvalue {i32, i1} %res, 0
6707 %obit = extractvalue {i32, i1} %res, 1
6708 br i1 %obit, label %overflow, label %normal
6709</pre>
6710
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6711</div>
6712
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6713<!-- _______________________________________________________________________ -->
6714<div class="doc_subsubsection">
6715 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6716</div>
6717
6718<div class="doc_text">
6719
6720<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6721<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]6722 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6723
6724<pre>
6725 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6726 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6727 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6728</pre>
6729
6730<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6731<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6732 a unsigned multiplication of the two arguments, and indicate whether an
6733 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6734
6735<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6736<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]6737 be of integer types of any bit width, but they must have the same bit
6738 width. The second element of the result structure must be of
6739 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6740 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6741
6742<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6743<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6744 an unsigned multiplication of the two arguments. They return a structure
6745 &mdash; the first element of which is the multiplication, and the second
6746 element of which is a bit specifying if the unsigned multiplication resulted
6747 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6748
6749<h5>Examples:</h5>
6750<pre>
6751 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6752 %sum = extractvalue {i32, i1} %res, 0
6753 %obit = extractvalue {i32, i1} %res, 1
6754 br i1 %obit, label %overflow, label %normal
6755</pre>
6756
6757</div>
6758
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6759<!-- ======================================================================= -->
6760<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6761 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6762</div>
6763
6764<div class="doc_text">
6765
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6766<p>Half precision floating point is a storage-only format. This means that it is
6767 a dense encoding (in memory) but does not support computation in the
6768 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6769
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6770<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6771 value as an i16, then convert it to float with <a
6772 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6773 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6774 double etc). To store the value back to memory, it is first converted to
6775 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6776 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6777 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6778</div>
6779
6780<!-- _______________________________________________________________________ -->
6781<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6782 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6783</div>
6784
6785<div class="doc_text">
6786
6787<h5>Syntax:</h5>
6788<pre>
6789 declare i16 @llvm.convert.to.fp16(f32 %a)
6790</pre>
6791
6792<h5>Overview:</h5>
6793<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6794 a conversion from single precision floating point format to half precision
6795 floating point format.</p>
6796
6797<h5>Arguments:</h5>
6798<p>The intrinsic function contains single argument - the value to be
6799 converted.</p>
6800
6801<h5>Semantics:</h5>
6802<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6803 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6804 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6805 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6806
6807<h5>Examples:</h5>
6808<pre>
6809 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6810 store i16 %res, i16* @x, align 2
6811</pre>
6812
6813</div>
6814
6815<!-- _______________________________________________________________________ -->
6816<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6817 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6818</div>
6819
6820<div class="doc_text">
6821
6822<h5>Syntax:</h5>
6823<pre>
6824 declare f32 @llvm.convert.from.fp16(i16 %a)
6825</pre>
6826
6827<h5>Overview:</h5>
6828<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6829 a conversion from half precision floating point format to single precision
6830 floating point format.</p>
6831
6832<h5>Arguments:</h5>
6833<p>The intrinsic function contains single argument - the value to be
6834 converted.</p>
6835
6836<h5>Semantics:</h5>
6837<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6838 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6839 precision floating point format. The input half-float value is represented by
6840 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6841
6842<h5>Examples:</h5>
6843<pre>
6844 %a = load i16* @x, align 2
6845 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6846</pre>
6847
6848</div>
6849
6850<!-- ======================================================================= -->
6851<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6852 <a name="int_debugger">Debugger Intrinsics</a>
6853</div>
6854
6855<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6857<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6858 prefix), are described in
6859 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6860 Level Debugging</a> document.</p>
6861
6862</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6863
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6864<!-- ======================================================================= -->
6865<div class="doc_subsection">
6866 <a name="int_eh">Exception Handling Intrinsics</a>
6867</div>
6868
6869<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870
6871<p>The LLVM exception handling intrinsics (which all start with
6872 <tt>llvm.eh.</tt> prefix), are described in
6873 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6874 Handling</a> document.</p>
6875
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6876</div>
6877
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6878<!-- ======================================================================= -->
6879<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6880 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6881</div>
6882
6883<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6884
6885<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6886 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6887 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6888 function pointer lacking the nest parameter - the caller does not need to
6889 provide a value for it. Instead, the value to use is stored in advance in a
6890 "trampoline", a block of memory usually allocated on the stack, which also
6891 contains code to splice the nest value into the argument list. This is used
6892 to implement the GCC nested function address extension.</p>
6893
6894<p>For example, if the function is
6895 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6896 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6897 follows:</p>
6898
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6899<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6900 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6901 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6902 %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]6903 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6904</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6906<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6907 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6908
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6909</div>
6910
6911<!-- _______________________________________________________________________ -->
6912<div class="doc_subsubsection">
6913 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6914</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6915
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6916<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6918<h5>Syntax:</h5>
6919<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920 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]6921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6922
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6923<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6925 function pointer suitable for executing it.</p>
6926
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6927<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6928<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6929 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6930 sufficiently aligned block of memory; this memory is written to by the
6931 intrinsic. Note that the size and the alignment are target-specific - LLVM
6932 currently provides no portable way of determining them, so a front-end that
6933 generates this intrinsic needs to have some target-specific knowledge.
6934 The <tt>func</tt> argument must hold a function bitcast to
6935 an <tt>i8*</tt>.</p>
6936
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6939 dependent code, turning it into a function. A pointer to this function is
6940 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6941 function pointer type</a> before being called. The new function's signature
6942 is the same as that of <tt>func</tt> with any arguments marked with
6943 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6944 is allowed, and it must be of pointer type. Calling the new function is
6945 equivalent to calling <tt>func</tt> with the same argument list, but
6946 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6947 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6948 by <tt>tramp</tt> is modified, then the effect of any later call to the
6949 returned function pointer is undefined.</p>
6950
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6951</div>
6952
6953<!-- ======================================================================= -->
6954<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6955 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6956</div>
6957
6958<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6959
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6961 hardware constructs for atomic operations and memory synchronization. This
6962 provides an interface to the hardware, not an interface to the programmer. It
6963 is aimed at a low enough level to allow any programming models or APIs
6964 (Application Programming Interfaces) which need atomic behaviors to map
6965 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6966 hardware provides a "universal IR" for source languages, it also provides a
6967 starting point for developing a "universal" atomic operation and
6968 synchronization IR.</p>
6969
6970<p>These do <em>not</em> form an API such as high-level threading libraries,
6971 software transaction memory systems, atomic primitives, and intrinsic
6972 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6973 application libraries. The hardware interface provided by LLVM should allow
6974 a clean implementation of all of these APIs and parallel programming models.
6975 No one model or paradigm should be selected above others unless the hardware
6976 itself ubiquitously does so.</p>
6977
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6978</div>
6979
6980<!-- _______________________________________________________________________ -->
6981<div class="doc_subsubsection">
6982 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6983</div>
6984<div class="doc_text">
6985<h5>Syntax:</h5>
6986<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6987 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]6988</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6989
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6992 specific pairs of memory access types.</p>
6993
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6994<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6995<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6996 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6997 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6998 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000<ul>
7001 <li><tt>ll</tt>: load-load barrier</li>
7002 <li><tt>ls</tt>: load-store barrier</li>
7003 <li><tt>sl</tt>: store-load barrier</li>
7004 <li><tt>ss</tt>: store-store barrier</li>
7005 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7006</ul>
7007
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7008<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7009<p>This intrinsic causes the system to enforce some ordering constraints upon
7010 the loads and stores of the program. This barrier does not
7011 indicate <em>when</em> any events will occur, it only enforces
7012 an <em>order</em> in which they occur. For any of the specified pairs of load
7013 and store operations (f.ex. load-load, or store-load), all of the first
7014 operations preceding the barrier will complete before any of the second
7015 operations succeeding the barrier begin. Specifically the semantics for each
7016 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7018<ul>
7019 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7020 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7021 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7022 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7023 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7025 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7026 load after the barrier begins.</li>
7027</ul>
7028
7029<p>These semantics are applied with a logical "and" behavior when more than one
7030 is enabled in a single memory barrier intrinsic.</p>
7031
7032<p>Backends may implement stronger barriers than those requested when they do
7033 not support as fine grained a barrier as requested. Some architectures do
7034 not need all types of barriers and on such architectures, these become
7035 noops.</p>
7036
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7037<h5>Example:</h5>
7038<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7039%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7040%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041 store i32 4, %ptr
7042
7043%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7044 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7045 <i>; guarantee the above finishes</i>
7046 store i32 8, %ptr <i>; before this begins</i>
7047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7048
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7049</div>
7050
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7051<!-- _______________________________________________________________________ -->
7052<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7053 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7054</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7055
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7056<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7057
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7059<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7060 any integer bit width and for different address spaces. Not all targets
7061 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7062
7063<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7064 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7065 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7066 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7067 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]7068</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7070<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071<p>This loads a value in memory and compares it to a given value. If they are
7072 equal, it stores a new value into the memory.</p>
7073
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7074<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7076 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7077 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7078 this integer type. While any bit width integer may be used, targets may only
7079 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7080
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7081<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7082<p>This entire intrinsic must be executed atomically. It first loads the value
7083 in memory pointed to by <tt>ptr</tt> and compares it with the
7084 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7085 memory. The loaded value is yielded in all cases. This provides the
7086 equivalent of an atomic compare-and-swap operation within the SSA
7087 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7089<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7090<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7091%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7092%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7093 store i32 4, %ptr
7094
7095%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7096%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7097 <i>; yields {i32}:result1 = 4</i>
7098%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7099%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7100
7101%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7102%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7103 <i>; yields {i32}:result2 = 8</i>
7104%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7105
7106%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7107</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7109</div>
7110
7111<!-- _______________________________________________________________________ -->
7112<div class="doc_subsubsection">
7113 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7114</div>
7115<div class="doc_text">
7116<h5>Syntax:</h5>
7117
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7118<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7119 integer bit width. Not all targets support all bit widths however.</p>
7120
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7121<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7122 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7123 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7124 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7125 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]7126</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7127
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7128<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7129<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7130 the value from memory. It then stores the value in <tt>val</tt> in the memory
7131 at <tt>ptr</tt>.</p>
7132
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7135 the <tt>val</tt> argument and the result must be integers of the same bit
7136 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7137 integer type. The targets may only lower integer representations they
7138 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7140<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7141<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7142 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7143 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145<h5>Examples:</h5>
7146<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7147%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7148%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149 store i32 4, %ptr
7150
7151%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7152%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7153 <i>; yields {i32}:result1 = 4</i>
7154%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7155%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7156
7157%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7158%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159 <i>; yields {i32}:result2 = 8</i>
7160
7161%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7162%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7163</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165</div>
7166
7167<!-- _______________________________________________________________________ -->
7168<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7169 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170
7171</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7172
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7173<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7176<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7177 any integer bit width. Not all targets support all bit widths however.</p>
7178
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7179<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7180 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7181 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7182 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7183 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]7184</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7185
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7186<h5>Overview:</h5>
7187<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7188 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7189
7190<h5>Arguments:</h5>
7191<p>The intrinsic takes two arguments, the first a pointer to an integer value
7192 and the second an integer value. The result is also an integer value. These
7193 integer types can have any bit width, but they must all have the same bit
7194 width. The targets may only lower integer representations they support.</p>
7195
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7196<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7197<p>This intrinsic does a series of operations atomically. It first loads the
7198 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7199 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]7200
7201<h5>Examples:</h5>
7202<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7203%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7204%ptr = bitcast i8* %mallocP to i32*
7205 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7206%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7207 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7208%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7209 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7210%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7212%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7213</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7214
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7215</div>
7216
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7217<!-- _______________________________________________________________________ -->
7218<div class="doc_subsubsection">
7219 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7220
7221</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7222
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7223<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7224
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7225<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7226<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7227 any integer bit width and for different address spaces. Not all targets
7228 support all bit widths however.</p>
7229
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7230<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7231 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7232 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7233 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7234 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]7235</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7236
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7237<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7238<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7239 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7240
7241<h5>Arguments:</h5>
7242<p>The intrinsic takes two arguments, the first a pointer to an integer value
7243 and the second an integer value. The result is also an integer value. These
7244 integer types can have any bit width, but they must all have the same bit
7245 width. The targets may only lower integer representations they support.</p>
7246
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7247<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248<p>This intrinsic does a series of operations atomically. It first loads the
7249 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7250 result to <tt>ptr</tt>. It yields the original value stored
7251 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7252
7253<h5>Examples:</h5>
7254<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7255%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7256%ptr = bitcast i8* %mallocP to i32*
7257 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7258%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7259 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7260%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7261 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7262%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7263 <i>; yields {i32}:result3 = 2</i>
7264%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7265</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7267</div>
7268
7269<!-- _______________________________________________________________________ -->
7270<div class="doc_subsubsection">
7271 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7272 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7273 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7274 <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]7275</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7277<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7279<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7280<p>These are overloaded intrinsics. You can
7281 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7282 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7283 bit width and for different address spaces. Not all targets support all bit
7284 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7286<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7287 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7288 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7289 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7290 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]7291</pre>
7292
7293<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7294 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7295 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7296 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7297 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]7298</pre>
7299
7300<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7301 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7302 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7303 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7304 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]7305</pre>
7306
7307<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7308 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7309 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7310 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7311 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]7312</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7313
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7314<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7315<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7316 the value stored in memory at <tt>ptr</tt>. It yields the original value
7317 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319<h5>Arguments:</h5>
7320<p>These intrinsics take two arguments, the first a pointer to an integer value
7321 and the second an integer value. The result is also an integer value. These
7322 integer types can have any bit width, but they must all have the same bit
7323 width. The targets may only lower integer representations they support.</p>
7324
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7325<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7326<p>These intrinsics does a series of operations atomically. They first load the
7327 value stored at <tt>ptr</tt>. They then do the bitwise
7328 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7329 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7330
7331<h5>Examples:</h5>
7332<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7333%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7334%ptr = bitcast i8* %mallocP to i32*
7335 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7336%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7337 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7338%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7339 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7340%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7342%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7343 <i>; yields {i32}:result3 = FF</i>
7344%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7345</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7346
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7347</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7348
7349<!-- _______________________________________________________________________ -->
7350<div class="doc_subsubsection">
7351 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7352 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7353 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7354 <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]7355</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7356
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7357<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7358
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7359<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7360<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7361 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7362 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7363 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7364
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7365<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7366 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7367 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7368 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7369 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]7370</pre>
7371
7372<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7373 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7374 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7375 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7376 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]7377</pre>
7378
7379<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7380 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7381 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7382 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7383 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]7384</pre>
7385
7386<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7387 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7388 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7389 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7390 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]7391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7392
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7393<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7394<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7395 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7396 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7397
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7398<h5>Arguments:</h5>
7399<p>These intrinsics take two arguments, the first a pointer to an integer value
7400 and the second an integer value. The result is also an integer value. These
7401 integer types can have any bit width, but they must all have the same bit
7402 width. The targets may only lower integer representations they support.</p>
7403
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7404<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7405<p>These intrinsics does a series of operations atomically. They first load the
7406 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7407 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7408 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7409
7410<h5>Examples:</h5>
7411<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7412%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7413%ptr = bitcast i8* %mallocP to i32*
7414 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7415%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7416 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7417%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7418 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7419%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7420 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7421%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7422 <i>; yields {i32}:result3 = 8</i>
7423%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7425
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7426</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7427
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7428
7429<!-- ======================================================================= -->
7430<div class="doc_subsection">
7431 <a name="int_memorymarkers">Memory Use Markers</a>
7432</div>
7433
7434<div class="doc_text">
7435
7436<p>This class of intrinsics exists to information about the lifetime of memory
7437 objects and ranges where variables are immutable.</p>
7438
7439</div>
7440
7441<!-- _______________________________________________________________________ -->
7442<div class="doc_subsubsection">
7443 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7444</div>
7445
7446<div class="doc_text">
7447
7448<h5>Syntax:</h5>
7449<pre>
7450 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7451</pre>
7452
7453<h5>Overview:</h5>
7454<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7455 object's lifetime.</p>
7456
7457<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7458<p>The first argument is a constant integer representing the size of the
7459 object, or -1 if it is variable sized. The second argument is a pointer to
7460 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7461
7462<h5>Semantics:</h5>
7463<p>This intrinsic indicates that before this point in the code, the value of the
7464 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]7465 never be used and has an undefined value. A load from the pointer that
7466 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7467 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7468
7469</div>
7470
7471<!-- _______________________________________________________________________ -->
7472<div class="doc_subsubsection">
7473 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7474</div>
7475
7476<div class="doc_text">
7477
7478<h5>Syntax:</h5>
7479<pre>
7480 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7481</pre>
7482
7483<h5>Overview:</h5>
7484<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7485 object's lifetime.</p>
7486
7487<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7488<p>The first argument is a constant integer representing the size of the
7489 object, or -1 if it is variable sized. The second argument is a pointer to
7490 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7491
7492<h5>Semantics:</h5>
7493<p>This intrinsic indicates that after this point in the code, the value of the
7494 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7495 never be used and has an undefined value. Any stores into the memory object
7496 following this intrinsic may be removed as dead.
7497
7498</div>
7499
7500<!-- _______________________________________________________________________ -->
7501<div class="doc_subsubsection">
7502 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7503</div>
7504
7505<div class="doc_text">
7506
7507<h5>Syntax:</h5>
7508<pre>
7509 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7510</pre>
7511
7512<h5>Overview:</h5>
7513<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7514 a memory object will not change.</p>
7515
7516<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7517<p>The first argument is a constant integer representing the size of the
7518 object, or -1 if it is variable sized. The second argument is a pointer to
7519 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7520
7521<h5>Semantics:</h5>
7522<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7523 the return value, the referenced memory location is constant and
7524 unchanging.</p>
7525
7526</div>
7527
7528<!-- _______________________________________________________________________ -->
7529<div class="doc_subsubsection">
7530 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7531</div>
7532
7533<div class="doc_text">
7534
7535<h5>Syntax:</h5>
7536<pre>
7537 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7538</pre>
7539
7540<h5>Overview:</h5>
7541<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7542 a memory object are mutable.</p>
7543
7544<h5>Arguments:</h5>
7545<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7546 The second argument is a constant integer representing the size of the
7547 object, or -1 if it is variable sized and the third argument is a pointer
7548 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7549
7550<h5>Semantics:</h5>
7551<p>This intrinsic indicates that the memory is mutable again.</p>
7552
7553</div>
7554
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7555<!-- ======================================================================= -->
7556<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7557 <a name="int_general">General Intrinsics</a>
7558</div>
7559
7560<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7561
7562<p>This class of intrinsics is designed to be generic and has no specific
7563 purpose.</p>
7564
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7565</div>
7566
7567<!-- _______________________________________________________________________ -->
7568<div class="doc_subsubsection">
7569 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7570</div>
7571
7572<div class="doc_text">
7573
7574<h5>Syntax:</h5>
7575<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7576 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]7577</pre>
7578
7579<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7580<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7581
7582<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7583<p>The first argument is a pointer to a value, the second is a pointer to a
7584 global string, the third is a pointer to a global string which is the source
7585 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7586
7587<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7588<p>This intrinsic allows annotation of local variables with arbitrary strings.
7589 This can be useful for special purpose optimizations that want to look for
7590 these annotations. These have no other defined use, they are ignored by code
7591 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7592
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7593</div>
7594
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7595<!-- _______________________________________________________________________ -->
7596<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7597 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7598</div>
7599
7600<div class="doc_text">
7601
7602<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7603<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7604 any integer bit width.</p>
7605
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7606<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7607 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7608 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7609 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7610 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7611 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]7612</pre>
7613
7614<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7615<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7616
7617<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7618<p>The first argument is an integer value (result of some expression), the
7619 second is a pointer to a global string, the third is a pointer to a global
7620 string which is the source file name, and the last argument is the line
7621 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7622
7623<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7624<p>This intrinsic allows annotations to be put on arbitrary expressions with
7625 arbitrary strings. This can be useful for special purpose optimizations that
7626 want to look for these annotations. These have no other defined use, they
7627 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7628
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7629</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7630
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7631<!-- _______________________________________________________________________ -->
7632<div class="doc_subsubsection">
7633 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7634</div>
7635
7636<div class="doc_text">
7637
7638<h5>Syntax:</h5>
7639<pre>
7640 declare void @llvm.trap()
7641</pre>
7642
7643<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7644<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7645
7646<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7647<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7650<p>This intrinsics is lowered to the target dependent trap instruction. If the
7651 target does not have a trap instruction, this intrinsic will be lowered to
7652 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7653
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7654</div>
7655
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7656<!-- _______________________________________________________________________ -->
7657<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7658 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7659</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7660
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7661<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7662
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7663<h5>Syntax:</h5>
7664<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7665 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7666</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7667
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7668<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7669<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7670 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7671 ensure that it is placed on the stack before local variables.</p>
7672
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7673<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7675 arguments. The first argument is the value loaded from the stack
7676 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7677 that has enough space to hold the value of the guard.</p>
7678
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7679<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7680<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7681 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7682 stack. This is to ensure that if a local variable on the stack is
7683 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7684 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7685 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7686 function.</p>
7687
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7688</div>
7689
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7690<!-- _______________________________________________________________________ -->
7691<div class="doc_subsubsection">
7692 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7693</div>
7694
7695<div class="doc_text">
7696
7697<h5>Syntax:</h5>
7698<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7699 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7700 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7701</pre>
7702
7703<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7704<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7705 the optimizers to determine at compile time whether a) an operation (like
7706 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7707 runtime check for overflow isn't necessary. An object in this context means
7708 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7709
7710<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7711<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7712 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7713 is a boolean 0 or 1. This argument determines whether you want the
7714 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]7715 1, variables are not allowed.</p>
7716
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7717<h5>Semantics:</h5>
7718<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7719 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7720 depending on the <tt>type</tt> argument, if the size cannot be determined at
7721 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7722
7723</div>
7724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7725<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7726<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7727<address>
7728 <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]7732
7733 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7734 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7735 Last modified: $Date$
7736</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7738</body>
7739</html>