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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c476ed93f12de42f0d50ae53017b85dddc9ce129 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]910<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]919<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1133
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1134 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1135 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1136 meaning the function can be patched and/or hooked even while it is
1137 loaded into memory. On x86, the function prologue will be preceded
1138 by six bytes of padding and will begin with a two-byte instruction.
1139 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1140 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1141
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1142 <dt><tt><b>inlinehint</b></tt></dt>
1143 <dd>This attribute indicates that the source code contained a hint that inlining
1144 this function is desirable (such as the "inline" keyword in C/C++). It
1145 is just a hint; it imposes no requirements on the inliner.</dd>
1146
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1147 <dt><tt><b>naked</b></tt></dt>
1148 <dd>This attribute disables prologue / epilogue emission for the function.
1149 This can have very system-specific consequences.</dd>
1150
1151 <dt><tt><b>noimplicitfloat</b></tt></dt>
1152 <dd>This attributes disables implicit floating point instructions.</dd>
1153
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the inliner should never inline this
1156 function in any situation. This attribute may not be used together with
1157 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1158
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1159 <dt><tt><b>noredzone</b></tt></dt>
1160 <dd>This attribute indicates that the code generator should not use a red
1161 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1162
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1163 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1164 <dd>This function attribute indicates that the function never returns
1165 normally. This produces undefined behavior at runtime if the function
1166 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1167
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This function attribute indicates that the function never returns with an
1170 unwind or exceptional control flow. If the function does unwind, its
1171 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1172
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>optsize</b></tt></dt>
1174 <dd>This attribute suggests that optimization passes and code generator passes
1175 make choices that keep the code size of this function low, and otherwise
1176 do optimizations specifically to reduce code size.</dd>
1177
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1178 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1179 <dd>This attribute indicates that the function computes its result (or decides
1180 to unwind an exception) based strictly on its arguments, without
1181 dereferencing any pointer arguments or otherwise accessing any mutable
1182 state (e.g. memory, control registers, etc) visible to caller functions.
1183 It does not write through any pointer arguments
1184 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1185 changes any state visible to callers. This means that it cannot unwind
1186 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1187 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1188
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This attribute indicates that the function does not write through any
1191 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1192 arguments) or otherwise modify any state (e.g. memory, control registers,
1193 etc) visible to caller functions. It may dereference pointer arguments
1194 and read state that may be set in the caller. A readonly function always
1195 returns the same value (or unwinds an exception identically) when called
1196 with the same set of arguments and global state. It cannot unwind an
1197 exception by calling the <tt>C++</tt> exception throwing methods, but may
1198 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attribute indicates that the function should emit a stack smashing
1202 protector. It is in the form of a "canary"&mdash;a random value placed on
1203 the stack before the local variables that's checked upon return from the
1204 function to see if it has been overwritten. A heuristic is used to
1205 determine if a function needs stack protectors or not.<br>
1206<br>
1207 If a function that has an <tt>ssp</tt> attribute is inlined into a
1208 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1209 function will have an <tt>ssp</tt> attribute.</dd>
1210
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1211 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212 <dd>This attribute indicates that the function should <em>always</em> emit a
1213 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1214 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1215<br>
1216 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1217 function that doesn't have an <tt>sspreq</tt> attribute or which has
1218 an <tt>ssp</tt> attribute, then the resulting function will have
1219 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1220</dl>
1221
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1222</div>
1223
1224<!-- ======================================================================= -->
1225<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1226 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1227</div>
1228
1229<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230
1231<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1232 the GCC "file scope inline asm" blocks. These blocks are internally
1233 concatenated by LLVM and treated as a single unit, but may be separated in
1234 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1235
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1236<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1237module asm "inline asm code goes here"
1238module asm "more can go here"
1239</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1240
1241<p>The strings can contain any character by escaping non-printable characters.
1242 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1243 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1244
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1245<p>The inline asm code is simply printed to the machine code .s file when
1246 assembly code is generated.</p>
1247
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1248</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1249
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1250<!-- ======================================================================= -->
1251<div class="doc_subsection">
1252 <a name="datalayout">Data Layout</a>
1253</div>
1254
1255<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1256
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1257<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1258 data is to be laid out in memory. The syntax for the data layout is
1259 simply:</p>
1260
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1261<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262target datalayout = "<i>layout specification</i>"
1263</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1264
1265<p>The <i>layout specification</i> consists of a list of specifications
1266 separated by the minus sign character ('-'). Each specification starts with
1267 a letter and may include other information after the letter to define some
1268 aspect of the data layout. The specifications accepted are as follows:</p>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270<dl>
1271 <dt><tt>E</tt></dt>
1272 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1273 bits with the most significance have the lowest address location.</dd>
1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1276 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1277 the bits with the least significance have the lowest address
1278 location.</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>preferred</i> alignments. All sizes are in bits. Specifying
1283 the <i>pref</i> alignment is optional. If omitted, the
1284 preceding <tt>:</tt> should be omitted too.</dd>
1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1287 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1289
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1290 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1291 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292 <i>size</i>.</dd>
1293
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1294 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1295 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1296 <i>size</i>. Only values of <i>size</i> that are supported by the target
1297 will work. 32 (float) and 64 (double) are supported on all targets;
1298 80 or 128 (different flavors of long double) are also supported on some
1299 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1301 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1302 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303 <i>size</i>.</dd>
1304
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1305 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1306 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1308
1309 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1310 <dd>This specifies a set of native integer widths for the target CPU
1311 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1312 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1313 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1314 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1315</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1318 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 specifications in the <tt>datalayout</tt> keyword. The default specifications
1320 are given in this list:</p>
1321
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322<ul>
1323 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1324 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1326 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1327 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1328 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1329 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330 alignment of 64-bits</li>
1331 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1332 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1333 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1334 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1335 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1336 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338
1339<p>When LLVM is determining the alignment for a given type, it uses the
1340 following rules:</p>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342<ol>
1343 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344 specification is used.</li>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347 smallest integer type that is larger than the bitwidth of the sought type
1348 is used. If none of the specifications are larger than the bitwidth then
1349 the the largest integer type is used. For example, given the default
1350 specifications above, the i7 type will use the alignment of i8 (next
1351 largest) while both i65 and i256 will use the alignment of i64 (largest
1352 specified).</li>
1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355 largest vector type that is smaller than the sought vector type will be
1356 used as a fall back. This happens because &lt;128 x double&gt; can be
1357 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1359
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1361
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1365</div>
1366
1367<div class="doc_text">
1368
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1369<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1370with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1371is undefined. Pointer values are associated with address ranges
1372according to the following rules:</p>
1373
1374<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1375 <li>A pointer value is associated with the addresses associated with
1376 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1377 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1378 range of the variable's storage.</li>
1379 <li>The result value of an allocation instruction is associated with
1380 the address range of the allocated storage.</li>
1381 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1382 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1383 <li>An integer constant other than zero or a pointer value returned
1384 from a function not defined within LLVM may be associated with address
1385 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1386 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1387 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1388</ul>
1389
1390<p>A pointer value is <i>based</i> on another pointer value according
1391 to the following rules:</p>
1392
1393<ul>
1394 <li>A pointer value formed from a
1395 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1396 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1397 <li>The result value of a
1398 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1399 of the <tt>bitcast</tt>.</li>
1400 <li>A pointer value formed by an
1401 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1402 pointer values that contribute (directly or indirectly) to the
1403 computation of the pointer's value.</li>
1404 <li>The "<i>based</i> on" relationship is transitive.</li>
1405</ul>
1406
1407<p>Note that this definition of <i>"based"</i> is intentionally
1408 similar to the definition of <i>"based"</i> in C99, though it is
1409 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1410
1411<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1412<tt><a href="#i_load">load</a></tt> merely indicates the size and
1413alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1414interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1415<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1416and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>Consequently, type-based alias analysis, aka TBAA, aka
1419<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1420LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1421additional information which specialized optimization passes may use
1422to implement type-based alias analysis.</p>
1423
1424</div>
1425
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1426<!-- ======================================================================= -->
1427<div class="doc_subsection">
1428 <a name="volatile">Volatile Memory Accesses</a>
1429</div>
1430
1431<div class="doc_text">
1432
1433<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1434href="#i_store"><tt>store</tt></a>s, and <a
1435href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1436The optimizers must not change the number of volatile operations or change their
1437order of execution relative to other volatile operations. The optimizers
1438<i>may</i> change the order of volatile operations relative to non-volatile
1439operations. This is not Java's "volatile" and has no cross-thread
1440synchronization behavior.</p>
1441
1442</div>
1443
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1444<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1446<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1450<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1451 intermediate representation. Being typed enables a number of optimizations
1452 to be performed on the intermediate representation directly, without having
1453 to do extra analyses on the side before the transformation. A strong type
1454 system makes it easier to read the generated code and enables novel analyses
1455 and transformations that are not feasible to perform on normal three address
1456 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1457
1458</div>
1459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1465
1466<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1467
1468<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1470 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1472 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1473 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
1475 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476 <td><a href="#t_floating">floating point</a></td>
1477 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478 </tr>
1479 <tr>
1480 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481 <td><a href="#t_integer">integer</a>,
1482 <a href="#t_floating">floating point</a>,
1483 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1484 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1485 <a href="#t_struct">structure</a>,
1486 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1487 <a href="#t_label">label</a>,
1488 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1489 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1491 <tr>
1492 <td><a href="#t_primitive">primitive</a></td>
1493 <td><a href="#t_label">label</a>,
1494 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1496 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1497 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1498 </tr>
1499 <tr>
1500 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1501 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502 <a href="#t_function">function</a>,
1503 <a href="#t_pointer">pointer</a>,
1504 <a href="#t_struct">structure</a>,
1505 <a href="#t_pstruct">packed structure</a>,
1506 <a href="#t_vector">vector</a>,
1507 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1508 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1510 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1513<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1514 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1515 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1517</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1519<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1520<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1521
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1522<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1523
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1524<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1525 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1527</div>
1528
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1530<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1531
1532<div class="doc_text">
1533
1534<h5>Overview:</h5>
1535<p>The integer type is a very simple type that simply specifies an arbitrary
1536 bit width for the integer type desired. Any bit width from 1 bit to
1537 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1538
1539<h5>Syntax:</h5>
1540<pre>
1541 iN
1542</pre>
1543
1544<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1545 value.</p>
1546
1547<h5>Examples:</h5>
1548<table class="layout">
1549 <tr class="layout">
1550 <td class="left"><tt>i1</tt></td>
1551 <td class="left">a single-bit integer.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>i32</tt></td>
1555 <td class="left">a 32-bit integer.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>i1942652</tt></td>
1559 <td class="left">a really big integer of over 1 million bits.</td>
1560 </tr>
1561</table>
1562
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1563</div>
1564
1565<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1566<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1567
1568<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1569
1570<table>
1571 <tbody>
1572 <tr><th>Type</th><th>Description</th></tr>
1573 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1574 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1575 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1576 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1577 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1578 </tbody>
1579</table>
1580
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1581</div>
1582
1583<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1585
1586<div class="doc_text">
1587
1588<h5>Overview:</h5>
1589<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1590
1591<h5>Syntax:</h5>
1592<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1593 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1594</pre>
1595
1596</div>
1597
1598<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1599<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1600
1601<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1602
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1603<h5>Overview:</h5>
1604<p>The void type does not represent any value and has no size.</p>
1605
1606<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607<pre>
1608 void
1609</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1611</div>
1612
1613<!-- _______________________________________________________________________ -->
1614<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1615
1616<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1617
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1618<h5>Overview:</h5>
1619<p>The label type represents code labels.</p>
1620
1621<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<pre>
1623 label
1624</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1625
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626</div>
1627
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1628<!-- _______________________________________________________________________ -->
1629<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1630
1631<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1632
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1633<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1634<p>The metadata type represents embedded metadata. No derived types may be
1635 created from metadata except for <a href="#t_function">function</a>
1636 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1637
1638<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1639<pre>
1640 metadata
1641</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1642
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1643</div>
1644
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1645
1646<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1647<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The real power in LLVM comes from the derived types in the system. This is
1652 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1653 useful types. Each of these types contain one or more element types which
1654 may be a primitive type, or another derived type. For example, it is
1655 possible to have a two dimensional array, using an array as the element type
1656 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1657
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1658
1659</div>
1660
1661<!-- _______________________________________________________________________ -->
1662<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1663
1664<div class="doc_text">
1665
1666<p>Aggregate Types are a subset of derived types that can contain multiple
1667 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1668 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1669 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1670
1671</div>
1672
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1673<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1674<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680 sequentially in memory. The array type requires a size (number of elements)
1681 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1682
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1684<pre>
1685 [&lt;# elements&gt; x &lt;elementtype&gt;]
1686</pre>
1687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1688<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1689 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1690
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1691<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1692<table class="layout">
1693 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1694 <td class="left"><tt>[40 x i32]</tt></td>
1695 <td class="left">Array of 40 32-bit integer values.</td>
1696 </tr>
1697 <tr class="layout">
1698 <td class="left"><tt>[41 x i32]</tt></td>
1699 <td class="left">Array of 41 32-bit integer values.</td>
1700 </tr>
1701 <tr class="layout">
1702 <td class="left"><tt>[4 x i8]</tt></td>
1703 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1704 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1706<p>Here are some examples of multidimensional arrays:</p>
1707<table class="layout">
1708 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1709 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1710 <td class="left">3x4 array of 32-bit integer values.</td>
1711 </tr>
1712 <tr class="layout">
1713 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1714 <td class="left">12x10 array of single precision floating point values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1718 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1719 </tr>
1720</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1721
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1722<p>There is no restriction on indexing beyond the end of the array implied by
1723 a static type (though there are restrictions on indexing beyond the bounds
1724 of an allocated object in some cases). This means that single-dimension
1725 'variable sized array' addressing can be implemented in LLVM with a zero
1726 length array type. An implementation of 'pascal style arrays' in LLVM could
1727 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1728
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1735
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1737<p>The function type can be thought of as a function signature. It consists of
1738 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1739 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1740
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1742<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1743 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1744</pre>
1745
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1746<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1747 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1748 which indicates that the function takes a variable number of arguments.
1749 Variable argument functions can access their arguments with
1750 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1751 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1752 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1755<table class="layout">
1756 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1757 <td class="left"><tt>i32 (i32)</tt></td>
1758 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1759 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1760 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1761 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1762 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1763 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1764 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1765 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1766 </td>
1767 </tr><tr class="layout">
1768 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1769 <td class="left">A vararg function that takes at least one
1770 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1771 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1772 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1774 </tr><tr class="layout">
1775 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1776 <td class="left">A function taking an <tt>i32</tt>, returning a
1777 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1778 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1781
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1782</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1790<p>The structure type is used to represent a collection of data members together
1791 in memory. The packing of the field types is defined to match the ABI of the
1792 underlying processor. The elements of a structure may be any type that has a
1793 size.</p>
1794
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1795<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1796 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1797 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Structures in registers are accessed using the
1799 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1800 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1802<pre>
1803 { &lt;type list&gt; }
1804</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1807<table class="layout">
1808 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1809 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1810 <td class="left">A triple of three <tt>i32</tt> values</td>
1811 </tr><tr class="layout">
1812 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1817 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1820</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1824</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1825
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1826<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1828<h5>Overview:</h5>
1829<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1830 together in memory. There is no padding between fields. Further, the
1831 alignment of a packed structure is 1 byte. The elements of a packed
1832 structure may be any type that has a size.</p>
1833
1834<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1835 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1836 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1837
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt; { &lt;type list&gt; } &gt;
1841</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1843<h5>Examples:</h5>
1844<table class="layout">
1845 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1846 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1847 <td class="left">A triple of three <tt>i32</tt> values</td>
1848 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1849 <td class="left">
1850<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1851 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1852 second element is a <a href="#t_pointer">pointer</a> to a
1853 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1854 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855 </tr>
1856</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1858</div>
1859
1860<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1863<div class="doc_text">
1864
1865<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1866<p>The pointer type is used to specify memory locations.
1867 Pointers are commonly used to reference objects in memory.</p>
1868
1869<p>Pointer types may have an optional address space attribute defining the
1870 numbered address space where the pointed-to object resides. The default
1871 address space is number zero. The semantics of non-zero address
1872 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1873
1874<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1875 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1876
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1877<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1878<pre>
1879 &lt;type&gt; *
1880</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1882<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1883<table class="layout">
1884 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1885 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1886 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1887 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1888 </tr>
1889 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1890 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1891 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1892 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1893 <tt>i32</tt>.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1897 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1898 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1899 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1900</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1902</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1903
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1907<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1908
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910<p>A vector type is a simple derived type that represents a vector of elements.
1911 Vector types are used when multiple primitive data are operated in parallel
1912 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1913 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1915
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1917<pre>
1918 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1919</pre>
1920
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1921<p>The number of elements is a constant integer value larger than 0; elementtype
1922 may be any integer or floating point type. Vectors of size zero are not
1923 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1924
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1925<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1926<table class="layout">
1927 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1928 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1929 <td class="left">Vector of 4 32-bit integer values.</td>
1930 </tr>
1931 <tr class="layout">
1932 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1933 <td class="left">Vector of 8 32-bit floating-point values.</td>
1934 </tr>
1935 <tr class="layout">
1936 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1937 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938 </tr>
1939</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1940
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941</div>
1942
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943<!-- _______________________________________________________________________ -->
1944<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1945<div class="doc_text">
1946
1947<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1948<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1949 corresponds (for example) to the C notion of a forward declared structure
1950 type. In LLVM, opaque types can eventually be resolved to any type (not just
1951 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1952
1953<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1954<pre>
1955 opaque
1956</pre>
1957
1958<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1959<table class="layout">
1960 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>opaque</tt></td>
1962 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1963 </tr>
1964</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1965
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966</div>
1967
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1968<!-- ======================================================================= -->
1969<div class="doc_subsection">
1970 <a name="t_uprefs">Type Up-references</a>
1971</div>
1972
1973<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1974
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976<p>An "up reference" allows you to refer to a lexically enclosing type without
1977 requiring it to have a name. For instance, a structure declaration may
1978 contain a pointer to any of the types it is lexically a member of. Example
1979 of up references (with their equivalent as named type declarations)
1980 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1981
1982<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1983 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1984 { \2 }* %y = type { %y }*
1985 \1* %z = type %z*
1986</pre>
1987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An up reference is needed by the asmprinter for printing out cyclic types
1989 when there is no declared name for a type in the cycle. Because the
1990 asmprinter does not want to print out an infinite type string, it needs a
1991 syntax to handle recursive types that have no names (all names are optional
1992 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<h5>Syntax:</h5>
1995<pre>
1996 \&lt;level&gt;
1997</pre>
1998
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1999<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000
2001<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
2004 <td class="left"><tt>\1*</tt></td>
2005 <td class="left">Self-referential pointer.</td>
2006 </tr>
2007 <tr class="layout">
2008 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2009 <td class="left">Recursive structure where the upref refers to the out-most
2010 structure.</td>
2011 </tr>
2012</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2014</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2015
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<!-- *********************************************************************** -->
2017<div class="doc_section"> <a name="constants">Constants</a> </div>
2018<!-- *********************************************************************** -->
2019
2020<div class="doc_text">
2021
2022<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2023 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2024
2025</div>
2026
2027<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2028<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2029
2030<div class="doc_text">
2031
2032<dl>
2033 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2034 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2035 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038 <dd>Standard integers (such as '4') are constants of
2039 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2040 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2045 notation (see below). The assembler requires the exact decimal value of a
2046 floating-point constant. For example, the assembler accepts 1.25 but
2047 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2048 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2049
2050 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2051 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2052 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053</dl>
2054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2055<p>The one non-intuitive notation for constants is the hexadecimal form of
2056 floating point constants. For example, the form '<tt>double
2057 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2058 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2059 constants are required (and the only time that they are generated by the
2060 disassembler) is when a floating point constant must be emitted but it cannot
2061 be represented as a decimal floating point number in a reasonable number of
2062 digits. For example, NaN's, infinities, and other special values are
2063 represented in their IEEE hexadecimal format so that assembly and disassembly
2064 do not cause any bits to change in the constants.</p>
2065
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2066<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2067 represented using the 16-digit form shown above (which matches the IEEE754
2068 representation for double); float values must, however, be exactly
2069 representable as IEE754 single precision. Hexadecimal format is always used
2070 for long double, and there are three forms of long double. The 80-bit format
2071 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2072 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2073 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2074 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2075 currently supported target uses this format. Long doubles will only work if
2076 they match the long double format on your target. All hexadecimal formats
2077 are big-endian (sign bit at the left).</p>
2078
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2079<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2080</div>
2081
2082<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2083<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2084<a name="aggregateconstants"></a> <!-- old anchor -->
2085<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2086</div>
2087
2088<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2090<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2091 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2092
2093<dl>
2094 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2095 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2096 type definitions (a comma separated list of elements, surrounded by braces
2097 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2098 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2099 Structure constants must have <a href="#t_struct">structure type</a>, and
2100 the number and types of elements must match those specified by the
2101 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2102
2103 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2104 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2105 definitions (a comma separated list of elements, surrounded by square
2106 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2107 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2108 the number and types of elements must match those specified by the
2109 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2110
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2111 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2112 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113 definitions (a comma separated list of elements, surrounded by
2114 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2115 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2116 have <a href="#t_vector">vector type</a>, and the number and types of
2117 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2118
2119 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2121 value to zero of <em>any</em> type, including scalar and
2122 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2123 This is often used to avoid having to print large zero initializers
2124 (e.g. for large arrays) and is always exactly equivalent to using explicit
2125 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2126
2127 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2128 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2129 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2130 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2131 be interpreted as part of the instruction stream, metadata is a place to
2132 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2133</dl>
2134
2135</div>
2136
2137<!-- ======================================================================= -->
2138<div class="doc_subsection">
2139 <a name="globalconstants">Global Variable and Function Addresses</a>
2140</div>
2141
2142<div class="doc_text">
2143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2144<p>The addresses of <a href="#globalvars">global variables</a>
2145 and <a href="#functionstructure">functions</a> are always implicitly valid
2146 (link-time) constants. These constants are explicitly referenced when
2147 the <a href="#identifiers">identifier for the global</a> is used and always
2148 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2149 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2150
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2151<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2152@X = global i32 17
2153@Y = global i32 42
2154@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2155</pre>
2156
2157</div>
2158
2159<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2160<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2161<div class="doc_text">
2162
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2163<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2164 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2165 Undefined values may be of any type (other than '<tt>label</tt>'
2166 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2168<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2169 program is well defined no matter what value is used. This gives the
2170 compiler more freedom to optimize. Here are some examples of (potentially
2171 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2172
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2173
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2174<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2175 %A = add %X, undef
2176 %B = sub %X, undef
2177 %C = xor %X, undef
2178Safe:
2179 %A = undef
2180 %B = undef
2181 %C = undef
2182</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2183
2184<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2185 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2187<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 %A = or %X, undef
2189 %B = and %X, undef
2190Safe:
2191 %A = -1
2192 %B = 0
2193Unsafe:
2194 %A = undef
2195 %B = undef
2196</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2197
2198<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2199 For example, if <tt>%X</tt> has a zero bit, then the output of the
2200 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2201 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2202 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2203 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2204 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2205 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2206 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2207
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2208<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2209 %A = select undef, %X, %Y
2210 %B = select undef, 42, %Y
2211 %C = select %X, %Y, undef
2212Safe:
2213 %A = %X (or %Y)
2214 %B = 42 (or %Y)
2215 %C = %Y
2216Unsafe:
2217 %A = undef
2218 %B = undef
2219 %C = undef
2220</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2221
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2222<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2223 branch) conditions can go <em>either way</em>, but they have to come from one
2224 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2225 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2226 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2227 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2228 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2229 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2230
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2231<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2232 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2233
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2234 %B = undef
2235 %C = xor %B, %B
2236
2237 %D = undef
2238 %E = icmp lt %D, 4
2239 %F = icmp gte %D, 4
2240
2241Safe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245 %D = undef
2246 %E = undef
2247 %F = undef
2248</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2250<p>This example points out that two '<tt>undef</tt>' operands are not
2251 necessarily the same. This can be surprising to people (and also matches C
2252 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2253 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2254 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2255 its value over its "live range". This is true because the variable doesn't
2256 actually <em>have a live range</em>. Instead, the value is logically read
2257 from arbitrary registers that happen to be around when needed, so the value
2258 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2259 need to have the same semantics or the core LLVM "replace all uses with"
2260 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2261
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2262<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2263 %A = fdiv undef, %X
2264 %B = fdiv %X, undef
2265Safe:
2266 %A = undef
2267b: unreachable
2268</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2269
2270<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2271 value</em> and <em>undefined behavior</em>. An undefined value (like
2272 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2273 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2274 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2275 defined on SNaN's. However, in the second example, we can make a more
2276 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2277 arbitrary value, we are allowed to assume that it could be zero. Since a
2278 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2279 the operation does not execute at all. This allows us to delete the divide and
2280 all code after it. Because the undefined operation "can't happen", the
2281 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2282
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2283<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2284a: store undef -> %X
2285b: store %X -> undef
2286Safe:
2287a: &lt;deleted&gt;
2288b: unreachable
2289</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2290
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2291<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2292 undefined value can be assumed to not have any effect; we can assume that the
2293 value is overwritten with bits that happen to match what was already there.
2294 However, a store <em>to</em> an undefined location could clobber arbitrary
2295 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2296
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2297</div>
2298
2299<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2300<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2301<div class="doc_text">
2302
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2303<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2304 instead of representing an unspecified bit pattern, they represent the
2305 fact that an instruction or constant expression which cannot evoke side
2306 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2307 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2308
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2309<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2310 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2311 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2312
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2313<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2314
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2315<ul>
2316<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2317 their operands.</li>
2318
2319<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2320 to their dynamic predecessor basic block.</li>
2321
2322<li>Function arguments depend on the corresponding actual argument values in
2323 the dynamic callers of their functions.</li>
2324
2325<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2326 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2327 control back to them.</li>
2328
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2329<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2330 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2331 or exception-throwing call instructions that dynamically transfer control
2332 back to them.</li>
2333
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2334<li>Non-volatile loads and stores depend on the most recent stores to all of the
2335 referenced memory addresses, following the order in the IR
2336 (including loads and stores implied by intrinsics such as
2337 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2338
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2339<!-- TODO: In the case of multiple threads, this only applies if the store
2340 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2341
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2342<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2343
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2344<li>An instruction with externally visible side effects depends on the most
2345 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2346 the order in the IR. (This includes
2347 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2348
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2349<li>An instruction <i>control-depends</i> on a
2350 <a href="#terminators">terminator instruction</a>
2351 if the terminator instruction has multiple successors and the instruction
2352 is always executed when control transfers to one of the successors, and
2353 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2354
2355<li>Dependence is transitive.</li>
2356
2357</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2358
2359<p>Whenever a trap value is generated, all values which depend on it evaluate
2360 to trap. If they have side effects, the evoke their side effects as if each
2361 operand with a trap value were undef. If they have externally-visible side
2362 effects, the behavior is undefined.</p>
2363
2364<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2365
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2366<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2367entry:
2368 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2369 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2370 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2371 store i32 0, i32* %trap_yet_again ; undefined behavior
2372
2373 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2374 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2375
2376 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2377
2378 %narrowaddr = bitcast i32* @g to i16*
2379 %wideaddr = bitcast i32* @g to i64*
2380 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2381 %trap4 = load i64* %widaddr ; Returns a trap value.
2382
2383 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2384 %br i1 %cmp, %true, %end ; Branch to either destination.
2385
2386true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2387 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2388 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2389 br label %end
2390
2391end:
2392 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2393 ; Both edges into this PHI are
2394 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2395 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2396
2397 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2398 ; so this is defined (ignoring earlier
2399 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2400</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2401
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2402</div>
2403
2404<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2405<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2406 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2407<div class="doc_text">
2408
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2409<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2410
2411<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2412 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2413 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2414
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2415<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2416 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2417 comparisons against null. Pointer equality tests between labels addresses
2418 results in undefined behavior &mdash; though, again, comparison against null
2419 is ok, and no label is equal to the null pointer. This may be passed around
2420 as an opaque pointer sized value as long as the bits are not inspected. This
2421 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2422 long as the original value is reconstituted before the <tt>indirectbr</tt>
2423 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2424
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2425<p>Finally, some targets may provide defined semantics when using the value as
2426 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2427
2428</div>
2429
2430
2431<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2432<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2433</div>
2434
2435<div class="doc_text">
2436
2437<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2438 to be used as constants. Constant expressions may be of
2439 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2440 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2441 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2442
2443<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2444 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2445 <dd>Truncate a constant to another type. The bit size of CST must be larger
2446 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2447
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2448 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2449 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2450 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2451
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2452 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2453 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2454 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2455
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2456 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Truncate a floating point constant to another floating point type. The
2458 size of CST must be larger than the size of TYPE. Both types must be
2459 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2460
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2461 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Floating point extend a constant to another type. The size of CST must be
2463 smaller or equal to the size of TYPE. Both types must be floating
2464 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2465
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2466 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2467 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2468 constant. TYPE must be a scalar or vector integer type. CST must be of
2469 scalar or vector floating point type. Both CST and TYPE must be scalars,
2470 or vectors of the same number of elements. If the value won't fit in the
2471 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2472
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2473 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2474 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2475 constant. TYPE must be a scalar or vector integer type. CST must be of
2476 scalar or vector floating point type. Both CST and TYPE must be scalars,
2477 or vectors of the same number of elements. If the value won't fit in the
2478 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2479
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2480 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2481 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2482 constant. TYPE must be a scalar or vector floating point type. CST must be
2483 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2484 vectors of the same number of elements. If the value won't fit in the
2485 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2486
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2487 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2489 constant. TYPE must be a scalar or vector floating point type. CST must be
2490 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2491 vectors of the same number of elements. If the value won't fit in the
2492 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2495 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2497 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2498 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2499
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2502 type. CST must be of integer type. The CST value is zero extended,
2503 truncated, or unchanged to make it fit in a pointer size. This one is
2504 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2505
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2507 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2508 are the same as those for the <a href="#i_bitcast">bitcast
2509 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2510
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2512 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2513 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2514 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2515 instruction, the index list may have zero or more indexes, which are
2516 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2517
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2519 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2520
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2521 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2522 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2523
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2525 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2526
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2527 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2529 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2530
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2531 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2533 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2534
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2535 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2537 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2538
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2539 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2540 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2541 constants. The index list is interpreted in a similar manner as indices in
2542 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2543 index value must be specified.</dd>
2544
2545 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2546 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2547 constants. The index list is interpreted in a similar manner as indices in
2548 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2549 index value must be specified.</dd>
2550
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2551 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2553 be any of the <a href="#binaryops">binary</a>
2554 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2555 on operands are the same as those for the corresponding instruction
2556 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2557</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2558
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2559</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2560
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2561<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2562<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2563<!-- *********************************************************************** -->
2564
2565<!-- ======================================================================= -->
2566<div class="doc_subsection">
2567<a name="inlineasm">Inline Assembler Expressions</a>
2568</div>
2569
2570<div class="doc_text">
2571
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2572<p>LLVM supports inline assembler expressions (as opposed
2573 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2574 a special value. This value represents the inline assembler as a string
2575 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2576 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2577 expression has side effects, and a flag indicating whether the function
2578 containing the asm needs to align its stack conservatively. An example
2579 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2580
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2581<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2582i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2583</pre>
2584
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2586 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2587 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2588
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2589<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2590%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2591</pre>
2592
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2593<p>Inline asms with side effects not visible in the constraint list must be
2594 marked as having side effects. This is done through the use of the
2595 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2596
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2597<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2598call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2599</pre>
2600
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2601<p>In some cases inline asms will contain code that will not work unless the
2602 stack is aligned in some way, such as calls or SSE instructions on x86,
2603 yet will not contain code that does that alignment within the asm.
2604 The compiler should make conservative assumptions about what the asm might
2605 contain and should generate its usual stack alignment code in the prologue
2606 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2607
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2608<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2609call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2610</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2611
2612<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2613 first.</p>
2614
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2615<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2616 documented here. Constraints on what can be done (e.g. duplication, moving,
2617 etc need to be documented). This is probably best done by reference to
2618 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2619</div>
2620
2621<div class="doc_subsubsection">
2622<a name="inlineasm_md">Inline Asm Metadata</a>
2623</div>
2624
2625<div class="doc_text">
2626
2627<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2628 attached to it that contains a constant integer. If present, the code
2629 generator will use the integer as the location cookie value when report
2630 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2631 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2632 source code that produced it. For example:</p>
2633
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2634<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2635call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2636...
2637!42 = !{ i32 1234567 }
2638</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2639
2640<p>It is up to the front-end to make sense of the magic numbers it places in the
2641 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2642
2643</div>
2644
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2645<!-- ======================================================================= -->
2646<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2647 Strings</a>
2648</div>
2649
2650<div class="doc_text">
2651
2652<p>LLVM IR allows metadata to be attached to instructions in the program that
2653 can convey extra information about the code to the optimizers and code
2654 generator. One example application of metadata is source-level debug
2655 information. There are two metadata primitives: strings and nodes. All
2656 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2657 preceding exclamation point ('<tt>!</tt>').</p>
2658
2659<p>A metadata string is a string surrounded by double quotes. It can contain
2660 any character by escaping non-printable characters with "\xx" where "xx" is
2661 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2662
2663<p>Metadata nodes are represented with notation similar to structure constants
2664 (a comma separated list of elements, surrounded by braces and preceded by an
2665 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2666 10}</tt>". Metadata nodes can have any values as their operand.</p>
2667
2668<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2669 metadata nodes, which can be looked up in the module symbol table. For
2670 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2671
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2672<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2673 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2674
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2675 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2676 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2677 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2678
2679<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2680 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2681
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2682 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2683 %indvar.next = add i64 %indvar, 1, !dbg !21
2684 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2685</div>
2686
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2687
2688<!-- *********************************************************************** -->
2689<div class="doc_section">
2690 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2691</div>
2692<!-- *********************************************************************** -->
2693
2694<p>LLVM has a number of "magic" global variables that contain data that affect
2695code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2696of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2697section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2698by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2699
2700<!-- ======================================================================= -->
2701<div class="doc_subsection">
2702<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2703</div>
2704
2705<div class="doc_text">
2706
2707<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2708href="#linkage_appending">appending linkage</a>. This array contains a list of
2709pointers to global variables and functions which may optionally have a pointer
2710cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2711
2712<pre>
2713 @X = global i8 4
2714 @Y = global i32 123
2715
2716 @llvm.used = appending global [2 x i8*] [
2717 i8* @X,
2718 i8* bitcast (i32* @Y to i8*)
2719 ], section "llvm.metadata"
2720</pre>
2721
2722<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2723compiler, assembler, and linker are required to treat the symbol as if there is
2724a reference to the global that it cannot see. For example, if a variable has
2725internal linkage and no references other than that from the <tt>@llvm.used</tt>
2726list, it cannot be deleted. This is commonly used to represent references from
2727inline asms and other things the compiler cannot "see", and corresponds to
2728"attribute((used))" in GNU C.</p>
2729
2730<p>On some targets, the code generator must emit a directive to the assembler or
2731object file to prevent the assembler and linker from molesting the symbol.</p>
2732
2733</div>
2734
2735<!-- ======================================================================= -->
2736<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2737<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2738</div>
2739
2740<div class="doc_text">
2741
2742<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2743<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2744touching the symbol. On targets that support it, this allows an intelligent
2745linker to optimize references to the symbol without being impeded as it would be
2746by <tt>@llvm.used</tt>.</p>
2747
2748<p>This is a rare construct that should only be used in rare circumstances, and
2749should not be exposed to source languages.</p>
2750
2751</div>
2752
2753<!-- ======================================================================= -->
2754<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2755<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2756</div>
2757
2758<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2759<pre>
2760%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2761@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2762</pre>
2763<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.
2764</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2765
2766</div>
2767
2768<!-- ======================================================================= -->
2769<div class="doc_subsection">
2770<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2771</div>
2772
2773<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2774<pre>
2775%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2776@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2777</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2778
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2779<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.
2780</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2781
2782</div>
2783
2784
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2785<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2786<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2787<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2788
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2789<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2790
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2791<p>The LLVM instruction set consists of several different classifications of
2792 instructions: <a href="#terminators">terminator
2793 instructions</a>, <a href="#binaryops">binary instructions</a>,
2794 <a href="#bitwiseops">bitwise binary instructions</a>,
2795 <a href="#memoryops">memory instructions</a>, and
2796 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2798</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2800<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2801<div class="doc_subsection"> <a name="terminators">Terminator
2802Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2804<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2805
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2806<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2807 in a program ends with a "Terminator" instruction, which indicates which
2808 block should be executed after the current block is finished. These
2809 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2810 control flow, not values (the one exception being the
2811 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2812
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2813<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2814 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2815 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2816 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2817 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2818 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2819 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2820 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2821
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2822</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2824<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2825<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2826Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2827
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2828<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2830<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2831<pre>
2832 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]2833 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2838 a value) from a function back to the caller.</p>
2839
2840<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2841 value and then causes control flow, and one that just causes control flow to
2842 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2844<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2845<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2846 return value. The type of the return value must be a
2847 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2849<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2850 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2851 value or a return value with a type that does not match its type, or if it
2852 has a void return type and contains a '<tt>ret</tt>' instruction with a
2853 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2854
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2856<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2857 the calling function's context. If the caller is a
2858 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2859 instruction after the call. If the caller was an
2860 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2861 the beginning of the "normal" destination block. If the instruction returns
2862 a value, that value shall set the call or invoke instruction's return
2863 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2866<pre>
2867 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2868 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2869 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]2870</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2871
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2872</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2874<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2875
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2876<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2879<pre>
2880 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]2881</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2884<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2885 different basic block in the current function. There are two forms of this
2886 instruction, corresponding to a conditional branch and an unconditional
2887 branch.</p>
2888
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2889<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2890<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2891 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2892 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2893 target.</p>
2894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2895<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2896<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2897 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2898 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2899 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2902<pre>
2903Test:
2904 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2905 br i1 %cond, label %IfEqual, label %IfUnequal
2906IfEqual:
2907 <a href="#i_ret">ret</a> i32 1
2908IfUnequal:
2909 <a href="#i_ret">ret</a> i32 0
2910</pre>
2911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2912</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2915<div class="doc_subsubsection">
2916 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2917</div>
2918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2919<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2920
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2922<pre>
2923 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2924</pre>
2925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2927<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]2928 several different places. It is a generalization of the '<tt>br</tt>'
2929 instruction, allowing a branch to occur to one of many possible
2930 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2932<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2933<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2934 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2935 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2936 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2937
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2938<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2939<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2940 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2941 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2942 transferred to the corresponding destination; otherwise, control flow is
2943 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2944
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2945<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2946<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2947 <tt>switch</tt> instruction, this instruction may be code generated in
2948 different ways. For example, it could be generated as a series of chained
2949 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2950
2951<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2952<pre>
2953 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2954 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2955 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2956
2957 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2958 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2959
2960 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2961 switch i32 %val, label %otherwise [ i32 0, label %onzero
2962 i32 1, label %onone
2963 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2964</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2966</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2967
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2968
2969<!-- _______________________________________________________________________ -->
2970<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2971 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2972</div>
2973
2974<div class="doc_text">
2975
2976<h5>Syntax:</h5>
2977<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2978 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]2979</pre>
2980
2981<h5>Overview:</h5>
2982
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2983<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2984 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2985 "<tt>address</tt>". Address must be derived from a <a
2986 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2987
2988<h5>Arguments:</h5>
2989
2990<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2991 rest of the arguments indicate the full set of possible destinations that the
2992 address may point to. Blocks are allowed to occur multiple times in the
2993 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2994
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2995<p>This destination list is required so that dataflow analysis has an accurate
2996 understanding of the CFG.</p>
2997
2998<h5>Semantics:</h5>
2999
3000<p>Control transfers to the block specified in the address argument. All
3001 possible destination blocks must be listed in the label list, otherwise this
3002 instruction has undefined behavior. This implies that jumps to labels
3003 defined in other functions have undefined behavior as well.</p>
3004
3005<h5>Implementation:</h5>
3006
3007<p>This is typically implemented with a jump through a register.</p>
3008
3009<h5>Example:</h5>
3010<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3011 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3012</pre>
3013
3014</div>
3015
3016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3017<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3018<div class="doc_subsubsection">
3019 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3020</div>
3021
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3022<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3024<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3025<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3026 &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]3027 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3028</pre>
3029
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3030<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3031<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3032 function, with the possibility of control flow transfer to either the
3033 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3034 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3035 control flow will return to the "normal" label. If the callee (or any
3036 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3037 instruction, control is interrupted and continued at the dynamically nearest
3038 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3039
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3040<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3041<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3043<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3045 convention</a> the call should use. If none is specified, the call
3046 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3047
3048 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3049 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3050 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3051
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3052 <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]3053 function value being invoked. In most cases, this is a direct function
3054 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3055 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3056
3057 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3059
3060 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3061 signature argument types and parameter attributes. All arguments must be
3062 of <a href="#t_firstclass">first class</a> type. If the function
3063 signature indicates the function accepts a variable number of arguments,
3064 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3065
3066 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3068
3069 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3071
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3072 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3074 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3075</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3076
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3078<p>This instruction is designed to operate as a standard
3079 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3080 primary difference is that it establishes an association with a label, which
3081 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3082
3083<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3084 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3085 exception. Additionally, this is important for implementation of
3086 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088<p>For the purposes of the SSA form, the definition of the value returned by the
3089 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3090 block to the "normal" label. If the callee unwinds then no return value is
3091 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3092
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3093<p>Note that the code generator does not yet completely support unwind, and
3094that the invoke/unwind semantics are likely to change in future versions.</p>
3095
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3096<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3097<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3098 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3099 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3100 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3101 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3102</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3103
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3105
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3106<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3107
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3108<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3109Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3110
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3111<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3112
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3113<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3114<pre>
3115 unwind
3116</pre>
3117
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3118<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3119<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3120 at the first callee in the dynamic call stack which used
3121 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3122 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3123
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3124<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3125<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126 immediately halt. The dynamic call stack is then searched for the
3127 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3128 Once found, execution continues at the "exceptional" destination block
3129 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3130 instruction in the dynamic call chain, undefined behavior results.</p>
3131
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3132<p>Note that the code generator does not yet completely support unwind, and
3133that the invoke/unwind semantics are likely to change in future versions.</p>
3134
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3135</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3136
3137<!-- _______________________________________________________________________ -->
3138
3139<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3140Instruction</a> </div>
3141
3142<div class="doc_text">
3143
3144<h5>Syntax:</h5>
3145<pre>
3146 unreachable
3147</pre>
3148
3149<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3150<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151 instruction is used to inform the optimizer that a particular portion of the
3152 code is not reachable. This can be used to indicate that the code after a
3153 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154
3155<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3156<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3158</div>
3159
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3160<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3161<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3162
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3163<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3164
3165<p>Binary operators are used to do most of the computation in a program. They
3166 require two operands of the same type, execute an operation on them, and
3167 produce a single value. The operands might represent multiple data, as is
3168 the case with the <a href="#t_vector">vector</a> data type. The result value
3169 has the same type as its operands.</p>
3170
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3171<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3173</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3174
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3175<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3176<div class="doc_subsubsection">
3177 <a name="i_add">'<tt>add</tt>' Instruction</a>
3178</div>
3179
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3180<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3181
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3182<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3183<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3184 &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]3185 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3186 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3187 &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]3188</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3191<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3193<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3194<p>The two arguments to the '<tt>add</tt>' instruction must
3195 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3196 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3198<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3199<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3200
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201<p>If the sum has unsigned overflow, the result returned is the mathematical
3202 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]3203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204<p>Because LLVM integers use a two's complement representation, this instruction
3205 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3206
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3207<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3208 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3209 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3210 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3211 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3213<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
3215 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3216</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3217
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3218</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3220<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3221<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3222 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3223</div>
3224
3225<div class="doc_text">
3226
3227<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3228<pre>
3229 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3230</pre>
3231
3232<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3233<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3234
3235<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3236<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3238 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3239
3240<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3241<p>The value produced is the floating point sum of the two operands.</p>
3242
3243<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3244<pre>
3245 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3246</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3248</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3249
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3250<!-- _______________________________________________________________________ -->
3251<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3252 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3253</div>
3254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3255<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3257<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3258<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3259 &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]3260 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3261 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3262 &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]3263</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3265<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3266<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3268
3269<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3270 '<tt>neg</tt>' instruction present in most other intermediate
3271 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3272
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3273<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274<p>The two arguments to the '<tt>sub</tt>' instruction must
3275 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3276 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3278<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3280
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3282 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3283 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3284
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285<p>Because LLVM integers use a two's complement representation, this instruction
3286 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3287
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3288<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3289 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3290 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3291 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3292 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3294<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3295<pre>
3296 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3297 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3300</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3301
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3302<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3304 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3305</div>
3306
3307<div class="doc_text">
3308
3309<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3310<pre>
3311 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3312</pre>
3313
3314<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3315<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3317
3318<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319 '<tt>fneg</tt>' instruction present in most other intermediate
3320 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3321
3322<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3323<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3325 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3326
3327<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3328<p>The value produced is the floating point difference of the two operands.</p>
3329
3330<h5>Example:</h5>
3331<pre>
3332 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3333 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3334</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3335
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3336</div>
3337
3338<!-- _______________________________________________________________________ -->
3339<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3340 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3341</div>
3342
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3343<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3344
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3345<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3346<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3347 &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]3348 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3349 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3350 &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]3351</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3353<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3354<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3356<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3357<p>The two arguments to the '<tt>mul</tt>' instruction must
3358 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3359 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3361<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3362<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3363
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364<p>If the result of the multiplication has unsigned overflow, the result
3365 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3366 width of the result.</p>
3367
3368<p>Because LLVM integers use a two's complement representation, and the result
3369 is the same width as the operands, this instruction returns the correct
3370 result for both signed and unsigned integers. If a full product
3371 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3372 be sign-extended or zero-extended as appropriate to the width of the full
3373 product.</p>
3374
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3375<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3376 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3377 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3378 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3379 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3380
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3381<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3382<pre>
3383 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3386</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3387
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3388<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3389<div class="doc_subsubsection">
3390 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3391</div>
3392
3393<div class="doc_text">
3394
3395<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3396<pre>
3397 &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]3398</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3399
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3400<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3401<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3402
3403<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3404<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3405 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3406 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407
3408<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3409<p>The value produced is the floating point product of the two operands.</p>
3410
3411<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3412<pre>
3413 &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]3414</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3415
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3416</div>
3417
3418<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3419<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3420</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3422<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3424<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3425<pre>
3426 &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]3427</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3429<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3431
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3432<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3433<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3435 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3436
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3437<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3438<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3440<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3442
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3443<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3445<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446<pre>
3447 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3448</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3452<!-- _______________________________________________________________________ -->
3453<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3454</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3456<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3457
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3459<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3460 &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]3461 &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]3462</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3463
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3464<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3466
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3467<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3468<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3470 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3471
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3472<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473<p>The value produced is the signed integer quotient of the two operands rounded
3474 towards zero.</p>
3475
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3476<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3478
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3479<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480 undefined behavior; this is a rare case, but can occur, for example, by doing
3481 a 32-bit division of -2147483648 by -1.</p>
3482
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3483<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3484 <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]3485 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3486
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488<pre>
3489 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3492</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3493
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3494<!-- _______________________________________________________________________ -->
3495<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3496Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3498<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3500<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3501<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3502 &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]3503</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505<h5>Overview:</h5>
3506<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3507
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3508<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3509<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3510 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3511 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3512
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3513<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3514<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3515
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3516<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3517<pre>
3518 &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]3519</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3520
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3521</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3523<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3524<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3525</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3527<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3529<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530<pre>
3531 &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]3532</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3536 division of its two arguments.</p>
3537
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3538<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3539<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3540 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3541 values. Both arguments must have identical types.</p>
3542
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3543<h5>Semantics:</h5>
3544<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545 This instruction always performs an unsigned division to get the
3546 remainder.</p>
3547
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3548<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3550
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3551<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3553<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554<pre>
3555 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3556</pre>
3557
3558</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3560<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3561<div class="doc_subsubsection">
3562 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3563</div>
3564
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3565<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3567<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3568<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3569 &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]3570</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3571
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3572<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3574 division of its two operands. This instruction can also take
3575 <a href="#t_vector">vector</a> versions of the values in which case the
3576 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3577
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3579<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3581 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3582
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3584<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3586 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3587 a value. For more information about the difference,
3588 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3589 Math Forum</a>. For a table of how this is implemented in various languages,
3590 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3591 Wikipedia: modulo operation</a>.</p>
3592
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3593<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3595
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3596<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3597 Overflow also leads to undefined behavior; this is a rare case, but can
3598 occur, for example, by taking the remainder of a 32-bit division of
3599 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3600 lets srem be implemented using instructions that return both the result of
3601 the division and the remainder.)</p>
3602
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604<pre>
3605 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3606</pre>
3607
3608</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3610<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3611<div class="doc_subsubsection">
3612 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3613
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3614<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3615
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3616<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617<pre>
3618 &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]3619</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3623 its two operands.</p>
3624
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3625<h5>Arguments:</h5>
3626<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3628 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3629
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631<p>This instruction returns the <i>remainder</i> of a division. The remainder
3632 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3633
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3634<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3635<pre>
3636 &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]3637</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3639</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3640
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3641<!-- ======================================================================= -->
3642<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3643Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3644
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3645<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3646
3647<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3648 program. They are generally very efficient instructions and can commonly be
3649 strength reduced from other instructions. They require two operands of the
3650 same type, execute an operation on them, and produce a single value. The
3651 resulting value is the same type as its operands.</p>
3652
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3653</div>
3654
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3655<!-- _______________________________________________________________________ -->
3656<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3657Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3658
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3659<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3661<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<pre>
3663 &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]3664</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3665
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3666<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3668 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3669
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3670<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3671<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3672 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3673 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3674
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3675<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3676<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3677 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3678 is (statically or dynamically) negative or equal to or larger than the number
3679 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3680 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3681 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3682
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683<h5>Example:</h5>
3684<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3685 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3686 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3687 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3688 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3689 &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]3690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3692</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3696Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3698<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3700<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701<pre>
3702 &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]3703</pre>
3704
3705<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3707 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3708
3709<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3710<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3712 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3713
3714<h5>Semantics:</h5>
3715<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3716 significant bits of the result will be filled with zero bits after the shift.
3717 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3718 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3719 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3720 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3721
3722<h5>Example:</h5>
3723<pre>
3724 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3725 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3726 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3727 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3728 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3729 &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]3730</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3732</div>
3733
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3734<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3735<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3736Instruction</a> </div>
3737<div class="doc_text">
3738
3739<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<pre>
3741 &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]3742</pre>
3743
3744<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3746 operand shifted to the right a specified number of bits with sign
3747 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3748
3749<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3750<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3752 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753
3754<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3755<p>This instruction always performs an arithmetic shift right operation, The
3756 most significant bits of the result will be filled with the sign bit
3757 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3758 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3759 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3760 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3761
3762<h5>Example:</h5>
3763<pre>
3764 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3765 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3766 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3767 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3768 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3769 &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]3770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3772</div>
3773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3774<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3775<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3776Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3777
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3778<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3780<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3781<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3782 &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]3783</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3785<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3787 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3789<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3790<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3792 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3794<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3795<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3797<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3798 <tbody>
3799 <tr>
3800 <td>In0</td>
3801 <td>In1</td>
3802 <td>Out</td>
3803 </tr>
3804 <tr>
3805 <td>0</td>
3806 <td>0</td>
3807 <td>0</td>
3808 </tr>
3809 <tr>
3810 <td>0</td>
3811 <td>1</td>
3812 <td>0</td>
3813 </tr>
3814 <tr>
3815 <td>1</td>
3816 <td>0</td>
3817 <td>0</td>
3818 </tr>
3819 <tr>
3820 <td>1</td>
3821 <td>1</td>
3822 <td>1</td>
3823 </tr>
3824 </tbody>
3825</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3827<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3828<pre>
3829 &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]3830 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3831 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3832</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3833</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3834<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3835<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3837<div class="doc_text">
3838
3839<h5>Syntax:</h5>
3840<pre>
3841 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3842</pre>
3843
3844<h5>Overview:</h5>
3845<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3846 two operands.</p>
3847
3848<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3849<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3851 values. Both arguments must have identical types.</p>
3852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3853<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3854<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3856<table border="1" cellspacing="0" cellpadding="4">
3857 <tbody>
3858 <tr>
3859 <td>In0</td>
3860 <td>In1</td>
3861 <td>Out</td>
3862 </tr>
3863 <tr>
3864 <td>0</td>
3865 <td>0</td>
3866 <td>0</td>
3867 </tr>
3868 <tr>
3869 <td>0</td>
3870 <td>1</td>
3871 <td>1</td>
3872 </tr>
3873 <tr>
3874 <td>1</td>
3875 <td>0</td>
3876 <td>1</td>
3877 </tr>
3878 <tr>
3879 <td>1</td>
3880 <td>1</td>
3881 <td>1</td>
3882 </tr>
3883 </tbody>
3884</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3886<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887<pre>
3888 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3889 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3890 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3891</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3893</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3895<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3896<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3897Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3898
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3899<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3902<pre>
3903 &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]3904</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3908 its two operands. The <tt>xor</tt> is used to implement the "one's
3909 complement" operation, which is the "~" operator in C.</p>
3910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3912<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3914 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3916<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3917<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3919<table border="1" cellspacing="0" cellpadding="4">
3920 <tbody>
3921 <tr>
3922 <td>In0</td>
3923 <td>In1</td>
3924 <td>Out</td>
3925 </tr>
3926 <tr>
3927 <td>0</td>
3928 <td>0</td>
3929 <td>0</td>
3930 </tr>
3931 <tr>
3932 <td>0</td>
3933 <td>1</td>
3934 <td>1</td>
3935 </tr>
3936 <tr>
3937 <td>1</td>
3938 <td>0</td>
3939 <td>1</td>
3940 </tr>
3941 <tr>
3942 <td>1</td>
3943 <td>1</td>
3944 <td>0</td>
3945 </tr>
3946 </tbody>
3947</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3949<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950<pre>
3951 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3952 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3953 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3954 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3955</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3957</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3958
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3959<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3960<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3961 <a name="vectorops">Vector Operations</a>
3962</div>
3963
3964<div class="doc_text">
3965
3966<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 target-independent manner. These instructions cover the element-access and
3968 vector-specific operations needed to process vectors effectively. While LLVM
3969 does directly support these vector operations, many sophisticated algorithms
3970 will want to use target-specific intrinsics to take full advantage of a
3971 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3972
3973</div>
3974
3975<!-- _______________________________________________________________________ -->
3976<div class="doc_subsubsection">
3977 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3978</div>
3979
3980<div class="doc_text">
3981
3982<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3983<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3984 &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]3985</pre>
3986
3987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3989 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3990
3991
3992<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3993<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3994 of <a href="#t_vector">vector</a> type. The second operand is an index
3995 indicating the position from which to extract the element. The index may be
3996 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3997
3998<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3999<p>The result is a scalar of the same type as the element type of
4000 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4001 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4002 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4003
4004<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4005<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4006 &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]4007</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4008
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4010
4011<!-- _______________________________________________________________________ -->
4012<div class="doc_subsubsection">
4013 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4014</div>
4015
4016<div class="doc_text">
4017
4018<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4019<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4020 &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]4021</pre>
4022
4023<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4025 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4026
4027<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4029 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4030 whose type must equal the element type of the first operand. The third
4031 operand is an index indicating the position at which to insert the value.
4032 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4033
4034<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4036 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4037 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4038 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4039
4040<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4041<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4042 &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]4043</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4045</div>
4046
4047<!-- _______________________________________________________________________ -->
4048<div class="doc_subsubsection">
4049 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4050</div>
4051
4052<div class="doc_text">
4053
4054<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4055<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4056 &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]4057</pre>
4058
4059<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4060<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4061 from two input vectors, returning a vector with the same element type as the
4062 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4063
4064<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4066 with types that match each other. The third argument is a shuffle mask whose
4067 element type is always 'i32'. The result of the instruction is a vector
4068 whose length is the same as the shuffle mask and whose element type is the
4069 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4071<p>The shuffle mask operand is required to be a constant vector with either
4072 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4073
4074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075<p>The elements of the two input vectors are numbered from left to right across
4076 both of the vectors. The shuffle mask operand specifies, for each element of
4077 the result vector, which element of the two input vectors the result element
4078 gets. The element selector may be undef (meaning "don't care") and the
4079 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4080
4081<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4082<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4083 &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]4084 &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]4085 &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]4086 &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]4087 &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]4088 &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]4089 &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]4090 &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]4091</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4092
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4094
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4095<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4096<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4097 <a name="aggregateops">Aggregate Operations</a>
4098</div>
4099
4100<div class="doc_text">
4101
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4102<p>LLVM supports several instructions for working with
4103 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4104
4105</div>
4106
4107<!-- _______________________________________________________________________ -->
4108<div class="doc_subsubsection">
4109 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4110</div>
4111
4112<div class="doc_text">
4113
4114<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4115<pre>
4116 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4117</pre>
4118
4119<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4120<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4121 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4122
4123<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4125 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4126 <a href="#t_array">array</a> type. The operands are constant indices to
4127 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4129
4130<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131<p>The result is the value at the position in the aggregate specified by the
4132 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4133
4134<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4136 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4137</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4138
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4140
4141<!-- _______________________________________________________________________ -->
4142<div class="doc_subsubsection">
4143 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4144</div>
4145
4146<div class="doc_text">
4147
4148<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4149<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4150 &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]4151</pre>
4152
4153<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4154<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4155 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4156
4157<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4158<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4159 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4160 <a href="#t_array">array</a> type. The second operand is a first-class
4161 value to insert. The following operands are constant indices indicating
4162 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]4163 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4164 value to insert must have the same type as the value identified by the
4165 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4166
4167<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4168<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4169 that of <tt>val</tt> except that the value at the position specified by the
4170 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171
4172<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4173<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4174 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4175 %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]4176</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4177
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4178</div>
4179
4180
4181<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4182<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4183 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4184</div>
4185
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4186<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4187
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188<p>A key design point of an SSA-based representation is how it represents
4189 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4190 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4191 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4192
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4193</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4194
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4195<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4196<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4197 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4198</div>
4199
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4200<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4201
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4202<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4203<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4204 &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]4205</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4206
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4207<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4208<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209 currently executing function, to be automatically released when this function
4210 returns to its caller. The object is always allocated in the generic address
4211 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4213<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214<p>The '<tt>alloca</tt>' instruction
4215 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4216 runtime stack, returning a pointer of the appropriate type to the program.
4217 If "NumElements" is specified, it is the number of elements allocated,
4218 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4219 specified, the value result of the allocation is guaranteed to be aligned to
4220 at least that boundary. If not specified, or if zero, the target can choose
4221 to align the allocation on any convenient boundary compatible with the
4222 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4224<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4226<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4227<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4229 memory is automatically released when the function returns. The
4230 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4231 variables that must have an address available. When the function returns
4232 (either with the <tt><a href="#i_ret">ret</a></tt>
4233 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4234 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4235
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4236<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4237<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4238 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4239 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4240 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4241 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4242</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4243
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4244</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4246<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4247<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4248Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4250<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4251
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4252<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4253<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4254 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4255 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4256 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4257</pre>
4258
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4259<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4260<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4261
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4262<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4263<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4264 from which to load. The pointer must point to
4265 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4266 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4267 number or order of execution of this <tt>load</tt> with other <a
4268 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4269
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4270<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 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]4272 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273 alignment for the target. It is the responsibility of the code emitter to
4274 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4275 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4276 produce less efficient code. An alignment of 1 is always safe.</p>
4277
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4278<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4279 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4280 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4281 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4282 and code generator that this load is not expected to be reused in the cache.
4283 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4284 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4285
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4286<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4287<p>The location of memory pointed to is loaded. If the value being loaded is of
4288 scalar type then the number of bytes read does not exceed the minimum number
4289 of bytes needed to hold all bits of the type. For example, loading an
4290 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4291 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4292 is undefined if the value was not originally written using a store of the
4293 same type.</p>
4294
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4295<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296<pre>
4297 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4298 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4299 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4300</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4301
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4302</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4304<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4305<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4306Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4308<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4310<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4312 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>
4313 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]4314</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4316<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4317<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4319<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4321 and an address at which to store it. The type of the
4322 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4323 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4324 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4325 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4326 order of execution of this <tt>store</tt> with other <a
4327 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4328
4329<p>The optional constant "align" argument specifies the alignment of the
4330 operation (that is, the alignment of the memory address). A value of 0 or an
4331 omitted "align" argument means that the operation has the preferential
4332 alignment for the target. It is the responsibility of the code emitter to
4333 ensure that the alignment information is correct. Overestimating the
4334 alignment results in an undefined behavior. Underestimating the alignment may
4335 produce less efficient code. An alignment of 1 is always safe.</p>
4336
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4337<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4338 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4339 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4340 instruction tells the optimizer and code generator that this load is
4341 not expected to be reused in the cache. The code generator may
4342 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4343 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4344
4345
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4346<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4347<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4348 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4349 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4350 does not exceed the minimum number of bytes needed to hold all bits of the
4351 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4352 writing a value of a type like <tt>i20</tt> with a size that is not an
4353 integral number of bytes, it is unspecified what happens to the extra bits
4354 that do not belong to the type, but they will typically be overwritten.</p>
4355
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4356<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357<pre>
4358 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4359 store i32 3, i32* %ptr <i>; yields {void}</i>
4360 %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]4361</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4363</div>
4364
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4365<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4366<div class="doc_subsubsection">
4367 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4368</div>
4369
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4370<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4371
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4372<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4373<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4374 &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]4375 &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]4376</pre>
4377
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4378<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4379<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4380 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4381 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4382
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4383<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4384<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4385 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4386 elements of the aggregate object are indexed. The interpretation of each
4387 index is dependent on the type being indexed into. The first index always
4388 indexes the pointer value given as the first argument, the second index
4389 indexes a value of the type pointed to (not necessarily the value directly
4390 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4391 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4392 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4393 can never be pointers, since that would require loading the pointer before
4394 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4395
4396<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]4397 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4398 integer <b>constants</b> are allowed. When indexing into an array, pointer
4399 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]4400 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4401
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>For example, let's consider a C code fragment and how it gets compiled to
4403 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4404
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4405<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4406struct RT {
4407 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4408 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4409 char C;
4410};
4411struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4412 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4413 double Y;
4414 struct RT Z;
4415};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4416
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4417int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4418 return &amp;s[1].Z.B[5][13];
4419}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4420</pre>
4421
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4422<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4423
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4424<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4425%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4426%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4427
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4428define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4429entry:
4430 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4431 ret i32* %reg
4432}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4433</pre>
4434
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4435<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4436<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]4437 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4438 }</tt>' type, a structure. The second index indexes into the third element
4439 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4440 i8 }</tt>' type, another structure. The third index indexes into the second
4441 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4442 array. The two dimensions of the array are subscripted into, yielding an
4443 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4444 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4445
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4446<p>Note that it is perfectly legal to index partially through a structure,
4447 returning a pointer to an inner element. Because of this, the LLVM code for
4448 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4449
4450<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4451 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4452 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4453 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4454 %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]4455 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4456 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4457 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4458 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4459</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4460
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4461<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4462 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4463 base pointer is not an <i>in bounds</i> address of an allocated object,
4464 or if any of the addresses that would be formed by successive addition of
4465 the offsets implied by the indices to the base address with infinitely
4466 precise arithmetic are not an <i>in bounds</i> address of that allocated
4467 object. The <i>in bounds</i> addresses for an allocated object are all
4468 the addresses that point into the object, plus the address one byte past
4469 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4470
4471<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4472 the base address with silently-wrapping two's complement arithmetic, and
4473 the result value of the <tt>getelementptr</tt> may be outside the object
4474 pointed to by the base pointer. The result value may not necessarily be
4475 used to access memory though, even if it happens to point into allocated
4476 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4477 section for more information.</p>
4478
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479<p>The getelementptr instruction is often confusing. For some more insight into
4480 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4481
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4482<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4483<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4484 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4485 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4486 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4487 %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]4488 <i>; yields i8*:eptr</i>
4489 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4490 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4491 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4492</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4493
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4494</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4496<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4497<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4498</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4500<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4501
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4502<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503 which all take a single operand and a type. They perform various bit
4504 conversions on the operand.</p>
4505
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4506</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4507
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4508<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4509<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4510 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4511</div>
4512<div class="doc_text">
4513
4514<h5>Syntax:</h5>
4515<pre>
4516 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4517</pre>
4518
4519<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4520<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4521 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4522
4523<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4524<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4525 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4526 size and type of the result, which must be
4527 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4528 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4529 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4530
4531<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4532<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4533 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4534 source size must be larger than the destination size, <tt>trunc</tt> cannot
4535 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4536
4537<h5>Example:</h5>
4538<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4539 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4540 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4541 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4542</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4543
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4544</div>
4545
4546<!-- _______________________________________________________________________ -->
4547<div class="doc_subsubsection">
4548 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4549</div>
4550<div class="doc_text">
4551
4552<h5>Syntax:</h5>
4553<pre>
4554 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4555</pre>
4556
4557<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4558<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4560
4561
4562<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4563<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]4564 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4565 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]4566 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4567 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4568
4569<h5>Semantics:</h5>
4570<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]4571 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4572
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4573<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]4574
4575<h5>Example:</h5>
4576<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4577 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4578 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4579</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4580
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4581</div>
4582
4583<!-- _______________________________________________________________________ -->
4584<div class="doc_subsubsection">
4585 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4586</div>
4587<div class="doc_text">
4588
4589<h5>Syntax:</h5>
4590<pre>
4591 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4592</pre>
4593
4594<h5>Overview:</h5>
4595<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4596
4597<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4598<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]4599 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4600 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]4601 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603
4604<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4605<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4606 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4607 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4608
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4609<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]4610
4611<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4613 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4614 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4615</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4616
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4617</div>
4618
4619<!-- _______________________________________________________________________ -->
4620<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4621 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4622</div>
4623
4624<div class="doc_text">
4625
4626<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4627<pre>
4628 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4629</pre>
4630
4631<h5>Overview:</h5>
4632<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4633 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4634
4635<h5>Arguments:</h5>
4636<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4638 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]4639 <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]4640 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4641
4642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4643<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4644 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645 <a href="#t_floating">floating point</a> type. If the value cannot fit
4646 within the destination type, <tt>ty2</tt>, then the results are
4647 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4648
4649<h5>Example:</h5>
4650<pre>
4651 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4652 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4653</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4655</div>
4656
4657<!-- _______________________________________________________________________ -->
4658<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4659 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4660</div>
4661<div class="doc_text">
4662
4663<h5>Syntax:</h5>
4664<pre>
4665 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4666</pre>
4667
4668<h5>Overview:</h5>
4669<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]4670 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4671
4672<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4673<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4675 a <a href="#t_floating">floating point</a> type to cast it to. The source
4676 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4677
4678<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4679<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680 <a href="#t_floating">floating point</a> type to a larger
4681 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4682 used to make a <i>no-op cast</i> because it always changes bits. Use
4683 <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]4684
4685<h5>Example:</h5>
4686<pre>
4687 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4688 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4689</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4690
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4691</div>
4692
4693<!-- _______________________________________________________________________ -->
4694<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4695 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4696</div>
4697<div class="doc_text">
4698
4699<h5>Syntax:</h5>
4700<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4701 &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]4702</pre>
4703
4704<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4705<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4707
4708<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4710 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4711 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4712 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4713 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4714
4715<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4716<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4718 towards zero) unsigned integer value. If the value cannot fit
4719 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4720
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4721<h5>Example:</h5>
4722<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4723 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4724 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4725 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4726</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4728</div>
4729
4730<!-- _______________________________________________________________________ -->
4731<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4732 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4733</div>
4734<div class="doc_text">
4735
4736<h5>Syntax:</h5>
4737<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4738 &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]4739</pre>
4740
4741<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4742<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743 <a href="#t_floating">floating point</a> <tt>value</tt> to
4744 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4745
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4746<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4747<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4748 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4749 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4750 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4751 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4752
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4753<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4754<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4755 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4756 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4757 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4758
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4759<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4760<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4761 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4762 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4763 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4765
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4766</div>
4767
4768<!-- _______________________________________________________________________ -->
4769<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4770 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4771</div>
4772<div class="doc_text">
4773
4774<h5>Syntax:</h5>
4775<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4776 &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]4777</pre>
4778
4779<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4780<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4782
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4783<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4784<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]4785 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4786 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4787 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4788 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4789
4790<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4791<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4792 integer quantity and converts it to the corresponding floating point
4793 value. If the value cannot fit in the floating point value, the results are
4794 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4795
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4796<h5>Example:</h5>
4797<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4798 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4799 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4801
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4802</div>
4803
4804<!-- _______________________________________________________________________ -->
4805<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4806 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807</div>
4808<div class="doc_text">
4809
4810<h5>Syntax:</h5>
4811<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4812 &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]4813</pre>
4814
4815<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4816<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4817 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4818
4819<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4820<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]4821 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4822 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4823 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4824 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4825
4826<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4827<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4828 quantity and converts it to the corresponding floating point value. If the
4829 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4830
4831<h5>Example:</h5>
4832<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4833 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4834 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4835</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4836
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4837</div>
4838
4839<!-- _______________________________________________________________________ -->
4840<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4841 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4842</div>
4843<div class="doc_text">
4844
4845<h5>Syntax:</h5>
4846<pre>
4847 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4848</pre>
4849
4850<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4851<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4852 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4853
4854<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4855<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4856 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4857 <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]4858
4859<h5>Semantics:</h5>
4860<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4861 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4862 truncating or zero extending that value to the size of the integer type. If
4863 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4864 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4865 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4866 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4867
4868<h5>Example:</h5>
4869<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4870 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4871 %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]4872</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4873
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4874</div>
4875
4876<!-- _______________________________________________________________________ -->
4877<div class="doc_subsubsection">
4878 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4879</div>
4880<div class="doc_text">
4881
4882<h5>Syntax:</h5>
4883<pre>
4884 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4885</pre>
4886
4887<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4889 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4890
4891<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4892<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4893 value to cast, and a type to cast it to, which must be a
4894 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4895
4896<h5>Semantics:</h5>
4897<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4899 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4900 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4901 than the size of a pointer then a zero extension is done. If they are the
4902 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4903
4904<h5>Example:</h5>
4905<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4906 %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]4907 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4908 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4909</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4910
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4911</div>
4912
4913<!-- _______________________________________________________________________ -->
4914<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4915 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4916</div>
4917<div class="doc_text">
4918
4919<h5>Syntax:</h5>
4920<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4921 &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]4922</pre>
4923
4924<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4925<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4926 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4927
4928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4929<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4930 non-aggregate first class value, and a type to cast it to, which must also be
4931 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4932 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4933 identical. If the source type is a pointer, the destination type must also be
4934 a pointer. This instruction supports bitwise conversion of vectors to
4935 integers and to vectors of other types (as long as they have the same
4936 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4937
4938<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4939<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4940 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4941 this conversion. The conversion is done as if the <tt>value</tt> had been
4942 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4943 be converted to other pointer types with this instruction. To convert
4944 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4945 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4946
4947<h5>Example:</h5>
4948<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4949 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4950 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4951 %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]4952</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4954</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4955
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4956<!-- ======================================================================= -->
4957<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4958
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4959<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960
4961<p>The instructions in this category are the "miscellaneous" instructions, which
4962 defy better classification.</p>
4963
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4964</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4965
4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4968</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4969
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4970<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4972<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4973<pre>
4974 &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]4975</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4977<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4978<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4979 boolean values based on comparison of its two integer, integer vector, or
4980 pointer operands.</p>
4981
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4982<h5>Arguments:</h5>
4983<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984 the condition code indicating the kind of comparison to perform. It is not a
4985 value, just a keyword. The possible condition code are:</p>
4986
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4987<ol>
4988 <li><tt>eq</tt>: equal</li>
4989 <li><tt>ne</tt>: not equal </li>
4990 <li><tt>ugt</tt>: unsigned greater than</li>
4991 <li><tt>uge</tt>: unsigned greater or equal</li>
4992 <li><tt>ult</tt>: unsigned less than</li>
4993 <li><tt>ule</tt>: unsigned less or equal</li>
4994 <li><tt>sgt</tt>: signed greater than</li>
4995 <li><tt>sge</tt>: signed greater or equal</li>
4996 <li><tt>slt</tt>: signed less than</li>
4997 <li><tt>sle</tt>: signed less or equal</li>
4998</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4999
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5000<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5001 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5002 typed. They must also be identical types.</p>
5003
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5004<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5005<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5006 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5007 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]5008 result, as follows:</p>
5009
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5010<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5011 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012 <tt>false</tt> otherwise. No sign interpretation is necessary or
5013 performed.</li>
5014
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5015 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016 <tt>false</tt> otherwise. No sign interpretation is necessary or
5017 performed.</li>
5018
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5019 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5020 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5021
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5022 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5023 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5024 to <tt>op2</tt>.</li>
5025
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5026 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5028
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5029 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5031
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5032 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5033 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5034
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5035 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5037 to <tt>op2</tt>.</li>
5038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5041
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5042 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043 <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]5044</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5046<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5047 values are compared as if they were integers.</p>
5048
5049<p>If the operands are integer vectors, then they are compared element by
5050 element. The result is an <tt>i1</tt> vector with the same number of elements
5051 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5052
5053<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5054<pre>
5055 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5056 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5057 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5058 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5059 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5060 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5061</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5062
5063<p>Note that the code generator does not yet support vector types with
5064 the <tt>icmp</tt> instruction.</p>
5065
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5066</div>
5067
5068<!-- _______________________________________________________________________ -->
5069<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5070</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5072<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5074<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075<pre>
5076 &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]5077</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5079<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5081 values based on comparison of its operands.</p>
5082
5083<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]5084(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5085
5086<p>If the operands are floating point vectors, then the result type is a vector
5087 of boolean with the same number of elements as the operands being
5088 compared.</p>
5089
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5090<h5>Arguments:</h5>
5091<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5092 the condition code indicating the kind of comparison to perform. It is not a
5093 value, just a keyword. The possible condition code are:</p>
5094
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5095<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5096 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5097 <li><tt>oeq</tt>: ordered and equal</li>
5098 <li><tt>ogt</tt>: ordered and greater than </li>
5099 <li><tt>oge</tt>: ordered and greater than or equal</li>
5100 <li><tt>olt</tt>: ordered and less than </li>
5101 <li><tt>ole</tt>: ordered and less than or equal</li>
5102 <li><tt>one</tt>: ordered and not equal</li>
5103 <li><tt>ord</tt>: ordered (no nans)</li>
5104 <li><tt>ueq</tt>: unordered or equal</li>
5105 <li><tt>ugt</tt>: unordered or greater than </li>
5106 <li><tt>uge</tt>: unordered or greater than or equal</li>
5107 <li><tt>ult</tt>: unordered or less than </li>
5108 <li><tt>ule</tt>: unordered or less than or equal</li>
5109 <li><tt>une</tt>: unordered or not equal</li>
5110 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5111 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5112</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5114<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115 <i>unordered</i> means that either operand may be a QNAN.</p>
5116
5117<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5118 a <a href="#t_floating">floating point</a> type or
5119 a <a href="#t_vector">vector</a> of floating point type. They must have
5120 identical types.</p>
5121
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5122<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5123<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124 according to the condition code given as <tt>cond</tt>. If the operands are
5125 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5126 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5127 follows:</p>
5128
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5129<ol>
5130 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5131
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5132 <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]5133 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5134
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5135 <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]5136 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5137
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5138 <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]5139 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5140
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5141 <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]5142 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5143
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5144 <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]5145 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5146
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5147 <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]5148 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5149
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5150 <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]5151
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5152 <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]5153 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5154
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5155 <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]5156 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5157
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5160
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5161 <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]5162 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5163
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5164 <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]5165 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5166
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5169
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5170 <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]5171
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5172 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5173</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5174
5175<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5176<pre>
5177 &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]5178 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5179 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5180 &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]5181</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5182
5183<p>Note that the code generator does not yet support vector types with
5184 the <tt>fcmp</tt> instruction.</p>
5185
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5186</div>
5187
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5188<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5189<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5190 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5191</div>
5192
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5193<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5194
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5195<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5196<pre>
5197 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5198</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5199
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5200<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5201<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5202 SSA graph representing the function.</p>
5203
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5205<p>The type of the incoming values is specified with the first type field. After
5206 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5207 one pair for each predecessor basic block of the current block. Only values
5208 of <a href="#t_firstclass">first class</a> type may be used as the value
5209 arguments to the PHI node. Only labels may be used as the label
5210 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5211
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5212<p>There must be no non-phi instructions between the start of a basic block and
5213 the PHI instructions: i.e. PHI instructions must be first in a basic
5214 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5215
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5216<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5217 occur on the edge from the corresponding predecessor block to the current
5218 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5219 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5220
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5221<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5222<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5223 specified by the pair corresponding to the predecessor basic block that
5224 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5225
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5227<pre>
5228Loop: ; Infinite loop that counts from 0 on up...
5229 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5230 %nextindvar = add i32 %indvar, 1
5231 br label %Loop
5232</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5233
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5234</div>
5235
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5236<!-- _______________________________________________________________________ -->
5237<div class="doc_subsubsection">
5238 <a name="i_select">'<tt>select</tt>' Instruction</a>
5239</div>
5240
5241<div class="doc_text">
5242
5243<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5244<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5245 &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>
5246
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5247 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5248</pre>
5249
5250<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5251<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5252 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5253
5254
5255<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5256<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5257 values indicating the condition, and two values of the
5258 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5259 vectors and the condition is a scalar, then entire vectors are selected, not
5260 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5261
5262<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5263<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5264 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5265
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5266<p>If the condition is a vector of i1, then the value arguments must be vectors
5267 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5268
5269<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5270<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5271 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5272</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5273
5274<p>Note that the code generator does not yet support conditions
5275 with vector type.</p>
5276
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5277</div>
5278
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5279<!-- _______________________________________________________________________ -->
5280<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5281 <a name="i_call">'<tt>call</tt>' Instruction</a>
5282</div>
5283
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5284<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5285
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5286<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5287<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5288 &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]5289</pre>
5290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5291<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5292<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5294<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5295<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5296
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5297<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5298 <li>The optional "tail" marker indicates that the callee function does not
5299 access any allocas or varargs in the caller. Note that calls may be
5300 marked "tail" even if they do not occur before
5301 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5302 present, the function call is eligible for tail call optimization,
5303 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5304 optimized into a jump</a>. The code generator may optimize calls marked
5305 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5306 sibling call optimization</a> when the caller and callee have
5307 matching signatures, or 2) forced tail call optimization when the
5308 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5309 <ul>
5310 <li>Caller and callee both have the calling
5311 convention <tt>fastcc</tt>.</li>
5312 <li>The call is in tail position (ret immediately follows call and ret
5313 uses value of call or is void).</li>
5314 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5315 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5316 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5317 constraints are met.</a></li>
5318 </ul>
5319 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5320
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5321 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5322 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5323 defaults to using C calling conventions. The calling convention of the
5324 call must match the calling convention of the target function, or else the
5325 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5327 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5328 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5329 '<tt>inreg</tt>' attributes are valid here.</li>
5330
5331 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5332 type of the return value. Functions that return no value are marked
5333 <tt><a href="#t_void">void</a></tt>.</li>
5334
5335 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5336 being invoked. The argument types must match the types implied by this
5337 signature. This type can be omitted if the function is not varargs and if
5338 the function type does not return a pointer to a function.</li>
5339
5340 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5341 be invoked. In most cases, this is a direct function invocation, but
5342 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5343 to function value.</li>
5344
5345 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5346 signature argument types and parameter attributes. All arguments must be
5347 of <a href="#t_firstclass">first class</a> type. If the function
5348 signature indicates the function accepts a variable number of arguments,
5349 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5350
5351 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5352 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5353 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5354</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5356<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5357<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5358 a specified function, with its incoming arguments bound to the specified
5359 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5360 function, control flow continues with the instruction after the function
5361 call, and the return value of the function is bound to the result
5362 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5364<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5365<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5366 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5367 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5368 %X = tail call i32 @foo() <i>; yields i32</i>
5369 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5370 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5371
5372 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5373 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5374 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5375 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5376 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5377 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5378</pre>
5379
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5380<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5381standard C99 library as being the C99 library functions, and may perform
5382optimizations or generate code for them under that assumption. This is
5383something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5384freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5385
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5386</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5387
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5388<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5389<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5390 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5391</div>
5392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5393<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5394
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5395<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5396<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5397 &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]5398</pre>
5399
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5400<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5401<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5402 the "variable argument" area of a function call. It is used to implement the
5403 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5404
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5405<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5406<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5407 argument. It returns a value of the specified argument type and increments
5408 the <tt>va_list</tt> to point to the next argument. The actual type
5409 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5410
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5411<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5412<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5413 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5414 to the next argument. For more information, see the variable argument
5415 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5416
5417<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]5418 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5419 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5420
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5421<p><tt>va_arg</tt> is an LLVM instruction instead of
5422 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5423 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5424
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5425<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5426<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5427
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5428<p>Note that the code generator does not yet fully support va_arg on many
5429 targets. Also, it does not currently support va_arg with aggregate types on
5430 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5431
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5432</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5433
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5434<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5435<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5436<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5438<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5439
5440<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441 well known names and semantics and are required to follow certain
5442 restrictions. Overall, these intrinsics represent an extension mechanism for
5443 the LLVM language that does not require changing all of the transformations
5444 in LLVM when adding to the language (or the bitcode reader/writer, the
5445 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5446
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5447<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5448 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5449 begin with this prefix. Intrinsic functions must always be external
5450 functions: you cannot define the body of intrinsic functions. Intrinsic
5451 functions may only be used in call or invoke instructions: it is illegal to
5452 take the address of an intrinsic function. Additionally, because intrinsic
5453 functions are part of the LLVM language, it is required if any are added that
5454 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5456<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5457 family of functions that perform the same operation but on different data
5458 types. Because LLVM can represent over 8 million different integer types,
5459 overloading is used commonly to allow an intrinsic function to operate on any
5460 integer type. One or more of the argument types or the result type can be
5461 overloaded to accept any integer type. Argument types may also be defined as
5462 exactly matching a previous argument's type or the result type. This allows
5463 an intrinsic function which accepts multiple arguments, but needs all of them
5464 to be of the same type, to only be overloaded with respect to a single
5465 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5466
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5467<p>Overloaded intrinsics will have the names of its overloaded argument types
5468 encoded into its function name, each preceded by a period. Only those types
5469 which are overloaded result in a name suffix. Arguments whose type is matched
5470 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5471 can take an integer of any width and returns an integer of exactly the same
5472 integer width. This leads to a family of functions such as
5473 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5474 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5475 suffix is required. Because the argument's type is matched against the return
5476 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5477
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5478<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5481</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5482
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5483<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5484<div class="doc_subsection">
5485 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5486</div>
5487
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5488<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5490<p>Variable argument support is defined in LLVM with
5491 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5492 intrinsic functions. These functions are related to the similarly named
5493 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5494
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5495<p>All of these functions operate on arguments that use a target-specific value
5496 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5497 not define what this type is, so all transformations should be prepared to
5498 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5499
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5500<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]5501 instruction and the variable argument handling intrinsic functions are
5502 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5503
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5504<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5505define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5506 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5507 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5508 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5509 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5510
5511 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5512 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5513
5514 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5515 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5516 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5517 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5518 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5519
5520 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5521 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5522 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5523}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5524
5525declare void @llvm.va_start(i8*)
5526declare void @llvm.va_copy(i8*, i8*)
5527declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5528</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5529
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5530</div>
5531
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5532<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5533<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5534 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5535</div>
5536
5537
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5538<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5539
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5540<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5541<pre>
5542 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5543</pre>
5544
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5545<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5546<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5547 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]5548
5549<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5550<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]5551
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5552<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5553<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]5554 macro available in C. In a target-dependent way, it initializes
5555 the <tt>va_list</tt> element to which the argument points, so that the next
5556 call to <tt>va_arg</tt> will produce the first variable argument passed to
5557 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5558 need to know the last argument of the function as the compiler can figure
5559 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5561</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5562
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5564<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5565 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5566</div>
5567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5568<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5570<h5>Syntax:</h5>
5571<pre>
5572 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5573</pre>
5574
5575<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5576<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5577 which has been initialized previously
5578 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5579 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5580
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5581<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5582<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]5583
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5584<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5585<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]5586 macro available in C. In a target-dependent way, it destroys
5587 the <tt>va_list</tt> element to which the argument points. Calls
5588 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5589 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5590 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5592</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5593
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5594<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5595<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5596 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5597</div>
5598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5599<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5600
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5601<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5602<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5603 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5604</pre>
5605
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5606<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5607<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5608 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5611<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]5612 The second argument is a pointer to a <tt>va_list</tt> element to copy
5613 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5614
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5616<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]5617 macro available in C. In a target-dependent way, it copies the
5618 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5619 element. This intrinsic is necessary because
5620 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5621 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5623</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5624
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5625<!-- ======================================================================= -->
5626<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5627 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5628</div>
5629
5630<div class="doc_text">
5631
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5633Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5635roots on the stack</a>, as well as garbage collector implementations that
5636require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5637barriers. Front-ends for type-safe garbage collected languages should generate
5638these intrinsics to make use of the LLVM garbage collectors. For more details,
5639see <a href="GarbageCollection.html">Accurate Garbage Collection with
5640LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5641
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5642<p>The garbage collection intrinsics only operate on objects in the generic
5643 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5644
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5649 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5650</div>
5651
5652<div class="doc_text">
5653
5654<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5655<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5656 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5657</pre>
5658
5659<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5660<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]5661 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5662
5663<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5664<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665 root pointer. The second pointer (which must be either a constant or a
5666 global value address) contains the meta-data to be associated with the
5667 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5668
5669<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5670<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]5671 location. At compile-time, the code generator generates information to allow
5672 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5673 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5674 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5675
5676</div>
5677
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5678<!-- _______________________________________________________________________ -->
5679<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5680 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5681</div>
5682
5683<div class="doc_text">
5684
5685<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5686<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5687 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688</pre>
5689
5690<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5691<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692 locations, allowing garbage collector implementations that require read
5693 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5694
5695<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5696<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]5697 allocated from the garbage collector. The first object is a pointer to the
5698 start of the referenced object, if needed by the language runtime (otherwise
5699 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5700
5701<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5702<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5703 instruction, but may be replaced with substantially more complex code by the
5704 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5705 may only be used in a function which <a href="#gc">specifies a GC
5706 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707
5708</div>
5709
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5710<!-- _______________________________________________________________________ -->
5711<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5712 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5713</div>
5714
5715<div class="doc_text">
5716
5717<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5719 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724 locations, allowing garbage collector implementations that require write
5725 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5726
5727<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5728<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]5729 object to store it to, and the third is the address of the field of Obj to
5730 store to. If the runtime does not require a pointer to the object, Obj may
5731 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5732
5733<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5734<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5735 instruction, but may be replaced with substantially more complex code by the
5736 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5737 may only be used in a function which <a href="#gc">specifies a GC
5738 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739
5740</div>
5741
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5742<!-- ======================================================================= -->
5743<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5744 <a name="int_codegen">Code Generator Intrinsics</a>
5745</div>
5746
5747<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5748
5749<p>These intrinsics are provided by LLVM to expose special features that may
5750 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5751
5752</div>
5753
5754<!-- _______________________________________________________________________ -->
5755<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5756 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5757</div>
5758
5759<div class="doc_text">
5760
5761<h5>Syntax:</h5>
5762<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5763 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5764</pre>
5765
5766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5768 target-specific value indicating the return address of the current function
5769 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5770
5771<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772<p>The argument to this intrinsic indicates which function to return the address
5773 for. Zero indicates the calling function, one indicates its caller, etc.
5774 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775
5776<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5778 indicating the return address of the specified call frame, or zero if it
5779 cannot be identified. The value returned by this intrinsic is likely to be
5780 incorrect or 0 for arguments other than zero, so it should only be used for
5781 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5782
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5783<p>Note that calling this intrinsic does not prevent function inlining or other
5784 aggressive transformations, so the value returned may not be that of the
5785 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5786
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787</div>
5788
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789<!-- _______________________________________________________________________ -->
5790<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5791 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5792</div>
5793
5794<div class="doc_text">
5795
5796<h5>Syntax:</h5>
5797<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5798 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5799</pre>
5800
5801<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5802<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5803 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5804
5805<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5806<p>The argument to this intrinsic indicates which function to return the frame
5807 pointer for. Zero indicates the calling function, one indicates its caller,
5808 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5809
5810<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5812 indicating the frame address of the specified call frame, or zero if it
5813 cannot be identified. The value returned by this intrinsic is likely to be
5814 incorrect or 0 for arguments other than zero, so it should only be used for
5815 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5816
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817<p>Note that calling this intrinsic does not prevent function inlining or other
5818 aggressive transformations, so the value returned may not be that of the
5819 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5821</div>
5822
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5823<!-- _______________________________________________________________________ -->
5824<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5825 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5826</div>
5827
5828<div class="doc_text">
5829
5830<h5>Syntax:</h5>
5831<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5832 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5833</pre>
5834
5835<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5836<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5837 of the function stack, for use
5838 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5839 useful for implementing language features like scoped automatic variable
5840 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5841
5842<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5843<p>This intrinsic returns a opaque pointer value that can be passed
5844 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5845 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5846 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5847 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5848 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5849 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5850
5851</div>
5852
5853<!-- _______________________________________________________________________ -->
5854<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5855 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5856</div>
5857
5858<div class="doc_text">
5859
5860<h5>Syntax:</h5>
5861<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5862 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5863</pre>
5864
5865<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5866<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5867 the function stack to the state it was in when the
5868 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5869 executed. This is useful for implementing language features like scoped
5870 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5871
5872<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873<p>See the description
5874 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5875
5876</div>
5877
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5878<!-- _______________________________________________________________________ -->
5879<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5880 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5881</div>
5882
5883<div class="doc_text">
5884
5885<h5>Syntax:</h5>
5886<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5887 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]5888</pre>
5889
5890<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5892 insert a prefetch instruction if supported; otherwise, it is a noop.
5893 Prefetches have no effect on the behavior of the program but can change its
5894 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5895
5896<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5897<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5898 specifier determining if the fetch should be for a read (0) or write (1),
5899 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5900 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5901 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5902
5903<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904<p>This intrinsic does not modify the behavior of the program. In particular,
5905 prefetches cannot trap and do not produce a value. On targets that support
5906 this intrinsic, the prefetch can provide hints to the processor cache for
5907 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5908
5909</div>
5910
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5911<!-- _______________________________________________________________________ -->
5912<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5913 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5914</div>
5915
5916<div class="doc_text">
5917
5918<h5>Syntax:</h5>
5919<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5920 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5925 Counter (PC) in a region of code to simulators and other tools. The method
5926 is target specific, but it is expected that the marker will use exported
5927 symbols to transmit the PC of the marker. The marker makes no guarantees
5928 that it will remain with any specific instruction after optimizations. It is
5929 possible that the presence of a marker will inhibit optimizations. The
5930 intended use is to be inserted after optimizations to allow correlations of
5931 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5932
5933<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5935
5936<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5937<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5938 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5939
5940</div>
5941
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5944 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
5950<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5951 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5956 counter register (or similar low latency, high accuracy clocks) on those
5957 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5958 should map to RPCC. As the backing counters overflow quickly (on the order
5959 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5962<p>When directly supported, reading the cycle counter should not modify any
5963 memory. Implementations are allowed to either return a application specific
5964 value or a system wide value. On backends without support, this is lowered
5965 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5966
5967</div>
5968
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5969<!-- ======================================================================= -->
5970<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5971 <a name="int_libc">Standard C Library Intrinsics</a>
5972</div>
5973
5974<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5975
5976<p>LLVM provides intrinsics for a few important standard C library functions.
5977 These intrinsics allow source-language front-ends to pass information about
5978 the alignment of the pointer arguments to the code generator, providing
5979 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5980
5981</div>
5982
5983<!-- _______________________________________________________________________ -->
5984<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5985 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5986</div>
5987
5988<div class="doc_text">
5989
5990<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991<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]5992 integer bit width and for different address spaces. Not all targets support
5993 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5994
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5995<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5996 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]5997 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5998 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]5999 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6000</pre>
6001
6002<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6003<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6004 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6005
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6006<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6007 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6008 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6009
6010<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012<p>The first argument is a pointer to the destination, the second is a pointer
6013 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6014 number of bytes to copy, the fourth argument is the alignment of the
6015 source and destination locations, and the fifth is a boolean indicating a
6016 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6017
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6018<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]6019 then the caller guarantees that both the source and destination pointers are
6020 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6021
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6022<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6023 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6024 The detailed access behavior is not very cleanly specified and it is unwise
6025 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6026
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6027<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6028
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6030 source location to the destination location, which are not allowed to
6031 overlap. It copies "len" bytes of memory over. If the argument is known to
6032 be aligned to some boundary, this can be specified as the fourth argument,
6033 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6034
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6035</div>
6036
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6037<!-- _______________________________________________________________________ -->
6038<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6039 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6040</div>
6041
6042<div class="doc_text">
6043
6044<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6045<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]6046 width and for different address space. Not all targets support all bit
6047 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6048
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6049<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6050 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]6051 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6052 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]6053 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6054</pre>
6055
6056<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6058 source location to the destination location. It is similar to the
6059 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6060 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6061
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6063 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6064 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6065
6066<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6068<p>The first argument is a pointer to the destination, the second is a pointer
6069 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6070 number of bytes to copy, the fourth argument is the alignment of the
6071 source and destination locations, and the fifth is a boolean indicating a
6072 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6073
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6074<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]6075 then the caller guarantees that the source and destination pointers are
6076 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6077
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6078<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6079 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6080 The detailed access behavior is not very cleanly specified and it is unwise
6081 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6082
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6083<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6085<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6086 source location to the destination location, which may overlap. It copies
6087 "len" bytes of memory over. If the argument is known to be aligned to some
6088 boundary, this can be specified as the fourth argument, otherwise it should
6089 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6090
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6091</div>
6092
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6093<!-- _______________________________________________________________________ -->
6094<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6095 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6096</div>
6097
6098<div class="doc_text">
6099
6100<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6101<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]6102 width and for different address spaces. However, not all targets support all
6103 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6104
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6105<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6106 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6107 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6108 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6109 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6110</pre>
6111
6112<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6113<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6114 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6115
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6117 intrinsic does not return a value and takes extra alignment/volatile
6118 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6119
6120<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121<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]6122 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6123 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6124 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6125
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6126<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]6127 then the caller guarantees that the destination pointer is aligned to that
6128 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6129
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6130<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6131 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6132 The detailed access behavior is not very cleanly specified and it is unwise
6133 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6134
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6135<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6137 at the destination location. If the argument is known to be aligned to some
6138 boundary, this can be specified as the fourth argument, otherwise it should
6139 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6140
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6141</div>
6142
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6143<!-- _______________________________________________________________________ -->
6144<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6145 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6146</div>
6147
6148<div class="doc_text">
6149
6150<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6151<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6152 floating point or vector of floating point type. Not all targets support all
6153 types however.</p>
6154
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6155<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6156 declare float @llvm.sqrt.f32(float %Val)
6157 declare double @llvm.sqrt.f64(double %Val)
6158 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6159 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6160 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6161</pre>
6162
6163<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6164<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6165 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6166 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6167 behavior for negative numbers other than -0.0 (which allows for better
6168 optimization, because there is no need to worry about errno being
6169 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]6170
6171<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6172<p>The argument and return value are floating point numbers of the same
6173 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6174
6175<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6176<p>This function returns the sqrt of the specified operand if it is a
6177 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6178
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6179</div>
6180
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6181<!-- _______________________________________________________________________ -->
6182<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6183 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6184</div>
6185
6186<div class="doc_text">
6187
6188<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6189<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6190 floating point or vector of floating point type. Not all targets support all
6191 types however.</p>
6192
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6193<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6194 declare float @llvm.powi.f32(float %Val, i32 %power)
6195 declare double @llvm.powi.f64(double %Val, i32 %power)
6196 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6197 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6198 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6199</pre>
6200
6201<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6202<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6203 specified (positive or negative) power. The order of evaluation of
6204 multiplications is not defined. When a vector of floating point type is
6205 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6206
6207<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6208<p>The second argument is an integer power, and the first is a value to raise to
6209 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6210
6211<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6212<p>This function returns the first value raised to the second power with an
6213 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6214
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6215</div>
6216
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6217<!-- _______________________________________________________________________ -->
6218<div class="doc_subsubsection">
6219 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6220</div>
6221
6222<div class="doc_text">
6223
6224<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6225<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6226 floating point or vector of floating point type. Not all targets support all
6227 types however.</p>
6228
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6229<pre>
6230 declare float @llvm.sin.f32(float %Val)
6231 declare double @llvm.sin.f64(double %Val)
6232 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6233 declare fp128 @llvm.sin.f128(fp128 %Val)
6234 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6235</pre>
6236
6237<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6239
6240<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6241<p>The argument and return value are floating point numbers of the same
6242 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6243
6244<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6245<p>This function returns the sine of the specified operand, returning the same
6246 values as the libm <tt>sin</tt> functions would, and handles error conditions
6247 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6248
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6249</div>
6250
6251<!-- _______________________________________________________________________ -->
6252<div class="doc_subsubsection">
6253 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6254</div>
6255
6256<div class="doc_text">
6257
6258<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6259<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6260 floating point or vector of floating point type. Not all targets support all
6261 types however.</p>
6262
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6263<pre>
6264 declare float @llvm.cos.f32(float %Val)
6265 declare double @llvm.cos.f64(double %Val)
6266 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6267 declare fp128 @llvm.cos.f128(fp128 %Val)
6268 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6269</pre>
6270
6271<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6273
6274<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6275<p>The argument and return value are floating point numbers of the same
6276 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6277
6278<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6279<p>This function returns the cosine of the specified operand, returning the same
6280 values as the libm <tt>cos</tt> functions would, and handles error conditions
6281 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6282
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6283</div>
6284
6285<!-- _______________________________________________________________________ -->
6286<div class="doc_subsubsection">
6287 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6288</div>
6289
6290<div class="doc_text">
6291
6292<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6293<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6294 floating point or vector of floating point type. Not all targets support all
6295 types however.</p>
6296
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6297<pre>
6298 declare float @llvm.pow.f32(float %Val, float %Power)
6299 declare double @llvm.pow.f64(double %Val, double %Power)
6300 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6301 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6302 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6303</pre>
6304
6305<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6306<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6307 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6308
6309<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6310<p>The second argument is a floating point power, and the first is a value to
6311 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6312
6313<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6314<p>This function returns the first value raised to the second power, returning
6315 the same values as the libm <tt>pow</tt> functions would, and handles error
6316 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6317
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6318</div>
6319
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6320<!-- ======================================================================= -->
6321<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6322 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6323</div>
6324
6325<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6326
6327<p>LLVM provides intrinsics for a few important bit manipulation operations.
6328 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6329
6330</div>
6331
6332<!-- _______________________________________________________________________ -->
6333<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6334 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6335</div>
6336
6337<div class="doc_text">
6338
6339<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6340<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6341 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6342
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6343<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6344 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6345 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6346 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6347</pre>
6348
6349<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6350<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6351 values with an even number of bytes (positive multiple of 16 bits). These
6352 are useful for performing operations on data that is not in the target's
6353 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6354
6355<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6356<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6357 and low byte of the input i16 swapped. Similarly,
6358 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6359 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6360 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6361 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6362 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6363 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6364
6365</div>
6366
6367<!-- _______________________________________________________________________ -->
6368<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6369 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6370</div>
6371
6372<div class="doc_text">
6373
6374<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6375<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]6376 width. Not all targets support all bit widths however.</p>
6377
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6378<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6379 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6380 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6381 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6382 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6383 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6384</pre>
6385
6386<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6388 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6389
6390<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6391<p>The only argument is the value to be counted. The argument may be of any
6392 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6393
6394<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6395<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]6396
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6397</div>
6398
6399<!-- _______________________________________________________________________ -->
6400<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6401 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6402</div>
6403
6404<div class="doc_text">
6405
6406<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6407<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6408 integer bit width. Not all targets support all bit widths however.</p>
6409
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6410<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6411 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6412 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6413 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6414 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6415 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6416</pre>
6417
6418<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6419<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6420 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6421
6422<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6423<p>The only argument is the value to be counted. The argument may be of any
6424 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6425
6426<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6427<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6428 zeros in a variable. If the src == 0 then the result is the size in bits of
6429 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6430
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6431</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6432
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6433<!-- _______________________________________________________________________ -->
6434<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6435 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6436</div>
6437
6438<div class="doc_text">
6439
6440<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6441<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6442 integer bit width. Not all targets support all bit widths however.</p>
6443
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6444<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6445 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6446 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6447 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6448 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6449 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6450</pre>
6451
6452<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6453<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6454 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6455
6456<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6457<p>The only argument is the value to be counted. The argument may be of any
6458 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6459
6460<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6461<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6462 zeros in a variable. If the src == 0 then the result is the size in bits of
6463 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6464
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6465</div>
6466
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6467<!-- ======================================================================= -->
6468<div class="doc_subsection">
6469 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6470</div>
6471
6472<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6473
6474<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6475
6476</div>
6477
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6478<!-- _______________________________________________________________________ -->
6479<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6480 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6481</div>
6482
6483<div class="doc_text">
6484
6485<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6486<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]6487 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6488
6489<pre>
6490 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6491 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6492 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6493</pre>
6494
6495<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6496<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6497 a signed addition of the two arguments, and indicate whether an overflow
6498 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6499
6500<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6501<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]6502 be of integer types of any bit width, but they must have the same bit
6503 width. The second element of the result structure must be of
6504 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6505 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6506
6507<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6508<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6509 a signed addition of the two variables. They return a structure &mdash; the
6510 first element of which is the signed summation, and the second element of
6511 which is a bit specifying if the signed summation resulted in an
6512 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6513
6514<h5>Examples:</h5>
6515<pre>
6516 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6517 %sum = extractvalue {i32, i1} %res, 0
6518 %obit = extractvalue {i32, i1} %res, 1
6519 br i1 %obit, label %overflow, label %normal
6520</pre>
6521
6522</div>
6523
6524<!-- _______________________________________________________________________ -->
6525<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6526 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527</div>
6528
6529<div class="doc_text">
6530
6531<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532<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]6533 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6534
6535<pre>
6536 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6537 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6538 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6539</pre>
6540
6541<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6542<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6543 an unsigned addition of the two arguments, and indicate whether a carry
6544 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6545
6546<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6547<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]6548 be of integer types of any bit width, but they must have the same bit
6549 width. The second element of the result structure must be of
6550 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6551 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6552
6553<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6554<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555 an unsigned addition of the two arguments. They return a structure &mdash;
6556 the first element of which is the sum, and the second element of which is a
6557 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6558
6559<h5>Examples:</h5>
6560<pre>
6561 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6562 %sum = extractvalue {i32, i1} %res, 0
6563 %obit = extractvalue {i32, i1} %res, 1
6564 br i1 %obit, label %carry, label %normal
6565</pre>
6566
6567</div>
6568
6569<!-- _______________________________________________________________________ -->
6570<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6571 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6572</div>
6573
6574<div class="doc_text">
6575
6576<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6577<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]6578 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6579
6580<pre>
6581 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6582 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6583 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6584</pre>
6585
6586<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6588 a signed subtraction of the two arguments, and indicate whether an overflow
6589 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6590
6591<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6592<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]6593 be of integer types of any bit width, but they must have the same bit
6594 width. The second element of the result structure must be of
6595 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6596 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6597
6598<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6599<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6600 a signed subtraction of the two arguments. They return a structure &mdash;
6601 the first element of which is the subtraction, and the second element of
6602 which is a bit specifying if the signed subtraction resulted in an
6603 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6604
6605<h5>Examples:</h5>
6606<pre>
6607 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6608 %sum = extractvalue {i32, i1} %res, 0
6609 %obit = extractvalue {i32, i1} %res, 1
6610 br i1 %obit, label %overflow, label %normal
6611</pre>
6612
6613</div>
6614
6615<!-- _______________________________________________________________________ -->
6616<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6617 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618</div>
6619
6620<div class="doc_text">
6621
6622<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623<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]6624 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6625
6626<pre>
6627 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6628 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6629 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6630</pre>
6631
6632<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6633<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634 an unsigned subtraction of the two arguments, and indicate whether an
6635 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6636
6637<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6638<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]6639 be of integer types of any bit width, but they must have the same bit
6640 width. The second element of the result structure must be of
6641 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6642 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6643
6644<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6645<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6646 an unsigned subtraction of the two arguments. They return a structure &mdash;
6647 the first element of which is the subtraction, and the second element of
6648 which is a bit specifying if the unsigned subtraction resulted in an
6649 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6650
6651<h5>Examples:</h5>
6652<pre>
6653 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6654 %sum = extractvalue {i32, i1} %res, 0
6655 %obit = extractvalue {i32, i1} %res, 1
6656 br i1 %obit, label %overflow, label %normal
6657</pre>
6658
6659</div>
6660
6661<!-- _______________________________________________________________________ -->
6662<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6663 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664</div>
6665
6666<div class="doc_text">
6667
6668<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669<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]6670 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671
6672<pre>
6673 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6674 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6675 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6676</pre>
6677
6678<h5>Overview:</h5>
6679
6680<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6681 a signed multiplication of the two arguments, and indicate whether an
6682 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6683
6684<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6685<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]6686 be of integer types of any bit width, but they must have the same bit
6687 width. The second element of the result structure must be of
6688 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6689 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690
6691<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6693 a signed multiplication of the two arguments. They return a structure &mdash;
6694 the first element of which is the multiplication, and the second element of
6695 which is a bit specifying if the signed multiplication resulted in an
6696 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6697
6698<h5>Examples:</h5>
6699<pre>
6700 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6701 %sum = extractvalue {i32, i1} %res, 0
6702 %obit = extractvalue {i32, i1} %res, 1
6703 br i1 %obit, label %overflow, label %normal
6704</pre>
6705
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6706</div>
6707
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6708<!-- _______________________________________________________________________ -->
6709<div class="doc_subsubsection">
6710 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6711</div>
6712
6713<div class="doc_text">
6714
6715<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6716<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]6717 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6718
6719<pre>
6720 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6721 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6722 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6723</pre>
6724
6725<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6726<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6727 a unsigned multiplication of the two arguments, and indicate whether an
6728 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6729
6730<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6731<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]6732 be of integer types of any bit width, but they must have the same bit
6733 width. The second element of the result structure must be of
6734 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6735 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6736
6737<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6738<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739 an unsigned multiplication of the two arguments. They return a structure
6740 &mdash; the first element of which is the multiplication, and the second
6741 element of which is a bit specifying if the unsigned multiplication resulted
6742 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6743
6744<h5>Examples:</h5>
6745<pre>
6746 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6747 %sum = extractvalue {i32, i1} %res, 0
6748 %obit = extractvalue {i32, i1} %res, 1
6749 br i1 %obit, label %overflow, label %normal
6750</pre>
6751
6752</div>
6753
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6754<!-- ======================================================================= -->
6755<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6756 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6757</div>
6758
6759<div class="doc_text">
6760
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6761<p>Half precision floating point is a storage-only format. This means that it is
6762 a dense encoding (in memory) but does not support computation in the
6763 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6764
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6765<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6766 value as an i16, then convert it to float with <a
6767 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6768 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6769 double etc). To store the value back to memory, it is first converted to
6770 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6771 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6772 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6773</div>
6774
6775<!-- _______________________________________________________________________ -->
6776<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6777 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6778</div>
6779
6780<div class="doc_text">
6781
6782<h5>Syntax:</h5>
6783<pre>
6784 declare i16 @llvm.convert.to.fp16(f32 %a)
6785</pre>
6786
6787<h5>Overview:</h5>
6788<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6789 a conversion from single precision floating point format to half precision
6790 floating point format.</p>
6791
6792<h5>Arguments:</h5>
6793<p>The intrinsic function contains single argument - the value to be
6794 converted.</p>
6795
6796<h5>Semantics:</h5>
6797<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6798 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6799 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6800 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6801
6802<h5>Examples:</h5>
6803<pre>
6804 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6805 store i16 %res, i16* @x, align 2
6806</pre>
6807
6808</div>
6809
6810<!-- _______________________________________________________________________ -->
6811<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6812 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6813</div>
6814
6815<div class="doc_text">
6816
6817<h5>Syntax:</h5>
6818<pre>
6819 declare f32 @llvm.convert.from.fp16(i16 %a)
6820</pre>
6821
6822<h5>Overview:</h5>
6823<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6824 a conversion from half precision floating point format to single precision
6825 floating point format.</p>
6826
6827<h5>Arguments:</h5>
6828<p>The intrinsic function contains single argument - the value to be
6829 converted.</p>
6830
6831<h5>Semantics:</h5>
6832<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6833 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6834 precision floating point format. The input half-float value is represented by
6835 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6836
6837<h5>Examples:</h5>
6838<pre>
6839 %a = load i16* @x, align 2
6840 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6841</pre>
6842
6843</div>
6844
6845<!-- ======================================================================= -->
6846<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6847 <a name="int_debugger">Debugger Intrinsics</a>
6848</div>
6849
6850<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6851
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6852<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6853 prefix), are described in
6854 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6855 Level Debugging</a> document.</p>
6856
6857</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6858
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6859<!-- ======================================================================= -->
6860<div class="doc_subsection">
6861 <a name="int_eh">Exception Handling Intrinsics</a>
6862</div>
6863
6864<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6865
6866<p>The LLVM exception handling intrinsics (which all start with
6867 <tt>llvm.eh.</tt> prefix), are described in
6868 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6869 Handling</a> document.</p>
6870
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6871</div>
6872
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6873<!-- ======================================================================= -->
6874<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6875 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6876</div>
6877
6878<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6879
6880<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6881 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6882 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883 function pointer lacking the nest parameter - the caller does not need to
6884 provide a value for it. Instead, the value to use is stored in advance in a
6885 "trampoline", a block of memory usually allocated on the stack, which also
6886 contains code to splice the nest value into the argument list. This is used
6887 to implement the GCC nested function address extension.</p>
6888
6889<p>For example, if the function is
6890 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6891 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6892 follows:</p>
6893
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6894<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6895 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6896 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6897 %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]6898 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6900
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6901<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6902 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6903
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6904</div>
6905
6906<!-- _______________________________________________________________________ -->
6907<div class="doc_subsubsection">
6908 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6909</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6911<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6913<h5>Syntax:</h5>
6914<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6915 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]6916</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6919<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6920 function pointer suitable for executing it.</p>
6921
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6923<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6924 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6925 sufficiently aligned block of memory; this memory is written to by the
6926 intrinsic. Note that the size and the alignment are target-specific - LLVM
6927 currently provides no portable way of determining them, so a front-end that
6928 generates this intrinsic needs to have some target-specific knowledge.
6929 The <tt>func</tt> argument must hold a function bitcast to
6930 an <tt>i8*</tt>.</p>
6931
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6932<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6933<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6934 dependent code, turning it into a function. A pointer to this function is
6935 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6936 function pointer type</a> before being called. The new function's signature
6937 is the same as that of <tt>func</tt> with any arguments marked with
6938 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6939 is allowed, and it must be of pointer type. Calling the new function is
6940 equivalent to calling <tt>func</tt> with the same argument list, but
6941 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6942 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6943 by <tt>tramp</tt> is modified, then the effect of any later call to the
6944 returned function pointer is undefined.</p>
6945
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6946</div>
6947
6948<!-- ======================================================================= -->
6949<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6950 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6951</div>
6952
6953<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6955<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6956 hardware constructs for atomic operations and memory synchronization. This
6957 provides an interface to the hardware, not an interface to the programmer. It
6958 is aimed at a low enough level to allow any programming models or APIs
6959 (Application Programming Interfaces) which need atomic behaviors to map
6960 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6961 hardware provides a "universal IR" for source languages, it also provides a
6962 starting point for developing a "universal" atomic operation and
6963 synchronization IR.</p>
6964
6965<p>These do <em>not</em> form an API such as high-level threading libraries,
6966 software transaction memory systems, atomic primitives, and intrinsic
6967 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6968 application libraries. The hardware interface provided by LLVM should allow
6969 a clean implementation of all of these APIs and parallel programming models.
6970 No one model or paradigm should be selected above others unless the hardware
6971 itself ubiquitously does so.</p>
6972
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6973</div>
6974
6975<!-- _______________________________________________________________________ -->
6976<div class="doc_subsubsection">
6977 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6978</div>
6979<div class="doc_text">
6980<h5>Syntax:</h5>
6981<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6982 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]6983</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6987 specific pairs of memory access types.</p>
6988
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6991 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6992 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6994
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6995<ul>
6996 <li><tt>ll</tt>: load-load barrier</li>
6997 <li><tt>ls</tt>: load-store barrier</li>
6998 <li><tt>sl</tt>: store-load barrier</li>
6999 <li><tt>ss</tt>: store-store barrier</li>
7000 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7001</ul>
7002
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7004<p>This intrinsic causes the system to enforce some ordering constraints upon
7005 the loads and stores of the program. This barrier does not
7006 indicate <em>when</em> any events will occur, it only enforces
7007 an <em>order</em> in which they occur. For any of the specified pairs of load
7008 and store operations (f.ex. load-load, or store-load), all of the first
7009 operations preceding the barrier will complete before any of the second
7010 operations succeeding the barrier begin. Specifically the semantics for each
7011 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7012
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7013<ul>
7014 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7015 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7016 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7017 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7018 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7019 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7020 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7021 load after the barrier begins.</li>
7022</ul>
7023
7024<p>These semantics are applied with a logical "and" behavior when more than one
7025 is enabled in a single memory barrier intrinsic.</p>
7026
7027<p>Backends may implement stronger barriers than those requested when they do
7028 not support as fine grained a barrier as requested. Some architectures do
7029 not need all types of barriers and on such architectures, these become
7030 noops.</p>
7031
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7032<h5>Example:</h5>
7033<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7034%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7035%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7036 store i32 4, %ptr
7037
7038%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7039 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7040 <i>; guarantee the above finishes</i>
7041 store i32 8, %ptr <i>; before this begins</i>
7042</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7044</div>
7045
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7046<!-- _______________________________________________________________________ -->
7047<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7048 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7049</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7051<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7053<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7054<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7055 any integer bit width and for different address spaces. Not all targets
7056 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7057
7058<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7059 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7060 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7061 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7062 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]7063</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7064
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066<p>This loads a value in memory and compares it to a given value. If they are
7067 equal, it stores a new value into the memory.</p>
7068
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7069<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7070<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7071 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7072 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7073 this integer type. While any bit width integer may be used, targets may only
7074 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7075
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7076<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7077<p>This entire intrinsic must be executed atomically. It first loads the value
7078 in memory pointed to by <tt>ptr</tt> and compares it with the
7079 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7080 memory. The loaded value is yielded in all cases. This provides the
7081 equivalent of an atomic compare-and-swap operation within the SSA
7082 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7083
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7084<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7085<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7086%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7087%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7088 store i32 4, %ptr
7089
7090%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7091%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7092 <i>; yields {i32}:result1 = 4</i>
7093%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7094%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7095
7096%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7097%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7098 <i>; yields {i32}:result2 = 8</i>
7099%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7100
7101%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7102</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7103
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7104</div>
7105
7106<!-- _______________________________________________________________________ -->
7107<div class="doc_subsubsection">
7108 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7109</div>
7110<div class="doc_text">
7111<h5>Syntax:</h5>
7112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7113<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7114 integer bit width. Not all targets support all bit widths however.</p>
7115
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7116<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7117 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7118 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7119 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7120 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]7121</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7122
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7123<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7124<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7125 the value from memory. It then stores the value in <tt>val</tt> in the memory
7126 at <tt>ptr</tt>.</p>
7127
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7128<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7129<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7130 the <tt>val</tt> argument and the result must be integers of the same bit
7131 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7132 integer type. The targets may only lower integer representations they
7133 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7134
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7135<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7136<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7137 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7138 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7140<h5>Examples:</h5>
7141<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7142%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7143%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144 store i32 4, %ptr
7145
7146%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7147%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7148 <i>; yields {i32}:result1 = 4</i>
7149%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7150%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7151
7152%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7153%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7154 <i>; yields {i32}:result2 = 8</i>
7155
7156%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7157%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7158</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7159
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7160</div>
7161
7162<!-- _______________________________________________________________________ -->
7163<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7164 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165
7166</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7172 any integer bit width. Not all targets support all bit widths however.</p>
7173
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7174<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7175 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7176 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7177 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7178 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]7179</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7181<h5>Overview:</h5>
7182<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7183 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7184
7185<h5>Arguments:</h5>
7186<p>The intrinsic takes two arguments, the first a pointer to an integer value
7187 and the second an integer value. The result is also an integer value. These
7188 integer types can have any bit width, but they must all have the same bit
7189 width. The targets may only lower integer representations they support.</p>
7190
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7192<p>This intrinsic does a series of operations atomically. It first loads the
7193 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7194 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]7195
7196<h5>Examples:</h5>
7197<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7198%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7199%ptr = bitcast i8* %mallocP to i32*
7200 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7201%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7202 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7203%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7204 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7205%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7207%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7208</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7209
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7210</div>
7211
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7212<!-- _______________________________________________________________________ -->
7213<div class="doc_subsubsection">
7214 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7215
7216</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7217
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7218<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7220<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7222 any integer bit width and for different address spaces. Not all targets
7223 support all bit widths however.</p>
7224
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7225<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7226 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7227 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7228 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7229 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]7230</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7231
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7232<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7233<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7234 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7235
7236<h5>Arguments:</h5>
7237<p>The intrinsic takes two arguments, the first a pointer to an integer value
7238 and the second an integer value. The result is also an integer value. These
7239 integer types can have any bit width, but they must all have the same bit
7240 width. The targets may only lower integer representations they support.</p>
7241
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7242<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243<p>This intrinsic does a series of operations atomically. It first loads the
7244 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7245 result to <tt>ptr</tt>. It yields the original value stored
7246 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7247
7248<h5>Examples:</h5>
7249<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7250%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7251%ptr = bitcast i8* %mallocP to i32*
7252 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7253%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7254 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7255%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7256 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7257%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7258 <i>; yields {i32}:result3 = 2</i>
7259%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7260</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7262</div>
7263
7264<!-- _______________________________________________________________________ -->
7265<div class="doc_subsubsection">
7266 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7267 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7268 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7269 <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]7270</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7271
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7272<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7273
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7274<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7275<p>These are overloaded intrinsics. You can
7276 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7277 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7278 bit width and for different address spaces. Not all targets support all bit
7279 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7280
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7282 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7283 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7284 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7285 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]7286</pre>
7287
7288<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7289 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7290 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7291 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7292 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]7293</pre>
7294
7295<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7296 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7297 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7298 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7299 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]7300</pre>
7301
7302<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7303 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7304 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7305 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7306 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]7307</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7309<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7310<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7311 the value stored in memory at <tt>ptr</tt>. It yields the original value
7312 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7313
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7314<h5>Arguments:</h5>
7315<p>These intrinsics take two arguments, the first a pointer to an integer value
7316 and the second an integer value. The result is also an integer value. These
7317 integer types can have any bit width, but they must all have the same bit
7318 width. The targets may only lower integer representations they support.</p>
7319
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7320<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7321<p>These intrinsics does a series of operations atomically. They first load the
7322 value stored at <tt>ptr</tt>. They then do the bitwise
7323 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7324 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7325
7326<h5>Examples:</h5>
7327<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7328%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7329%ptr = bitcast i8* %mallocP to i32*
7330 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7331%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7332 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7333%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7334 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7335%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7336 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7337%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338 <i>; yields {i32}:result3 = FF</i>
7339%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7340</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7342</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7343
7344<!-- _______________________________________________________________________ -->
7345<div class="doc_subsubsection">
7346 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7347 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7348 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7349 <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]7350</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7351
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7352<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7353
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7354<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7355<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7356 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7357 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7358 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7359
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7360<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7361 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7362 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7363 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7364 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]7365</pre>
7366
7367<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7368 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7369 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7370 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7371 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]7372</pre>
7373
7374<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7375 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7376 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7377 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7378 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]7379</pre>
7380
7381<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7382 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7383 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7384 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7385 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]7386</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7387
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7388<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7389<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7390 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7391 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7392
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7393<h5>Arguments:</h5>
7394<p>These intrinsics take two arguments, the first a pointer to an integer value
7395 and the second an integer value. The result is also an integer value. These
7396 integer types can have any bit width, but they must all have the same bit
7397 width. The targets may only lower integer representations they support.</p>
7398
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7399<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7400<p>These intrinsics does a series of operations atomically. They first load the
7401 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7402 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7403 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7404
7405<h5>Examples:</h5>
7406<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7407%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7408%ptr = bitcast i8* %mallocP to i32*
7409 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7410%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7411 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7412%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7413 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7414%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7415 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7416%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7417 <i>; yields {i32}:result3 = 8</i>
7418%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7419</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7420
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7421</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7422
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7423
7424<!-- ======================================================================= -->
7425<div class="doc_subsection">
7426 <a name="int_memorymarkers">Memory Use Markers</a>
7427</div>
7428
7429<div class="doc_text">
7430
7431<p>This class of intrinsics exists to information about the lifetime of memory
7432 objects and ranges where variables are immutable.</p>
7433
7434</div>
7435
7436<!-- _______________________________________________________________________ -->
7437<div class="doc_subsubsection">
7438 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7439</div>
7440
7441<div class="doc_text">
7442
7443<h5>Syntax:</h5>
7444<pre>
7445 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7446</pre>
7447
7448<h5>Overview:</h5>
7449<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7450 object's lifetime.</p>
7451
7452<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7453<p>The first argument is a constant integer representing the size of the
7454 object, or -1 if it is variable sized. The second argument is a pointer to
7455 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7456
7457<h5>Semantics:</h5>
7458<p>This intrinsic indicates that before this point in the code, the value of the
7459 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]7460 never be used and has an undefined value. A load from the pointer that
7461 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7462 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7463
7464</div>
7465
7466<!-- _______________________________________________________________________ -->
7467<div class="doc_subsubsection">
7468 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7469</div>
7470
7471<div class="doc_text">
7472
7473<h5>Syntax:</h5>
7474<pre>
7475 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7476</pre>
7477
7478<h5>Overview:</h5>
7479<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7480 object's lifetime.</p>
7481
7482<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7483<p>The first argument is a constant integer representing the size of the
7484 object, or -1 if it is variable sized. The second argument is a pointer to
7485 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7486
7487<h5>Semantics:</h5>
7488<p>This intrinsic indicates that after this point in the code, the value of the
7489 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7490 never be used and has an undefined value. Any stores into the memory object
7491 following this intrinsic may be removed as dead.
7492
7493</div>
7494
7495<!-- _______________________________________________________________________ -->
7496<div class="doc_subsubsection">
7497 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7498</div>
7499
7500<div class="doc_text">
7501
7502<h5>Syntax:</h5>
7503<pre>
7504 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7505</pre>
7506
7507<h5>Overview:</h5>
7508<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7509 a memory object will not change.</p>
7510
7511<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7512<p>The first argument is a constant integer representing the size of the
7513 object, or -1 if it is variable sized. The second argument is a pointer to
7514 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7515
7516<h5>Semantics:</h5>
7517<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7518 the return value, the referenced memory location is constant and
7519 unchanging.</p>
7520
7521</div>
7522
7523<!-- _______________________________________________________________________ -->
7524<div class="doc_subsubsection">
7525 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7526</div>
7527
7528<div class="doc_text">
7529
7530<h5>Syntax:</h5>
7531<pre>
7532 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7533</pre>
7534
7535<h5>Overview:</h5>
7536<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7537 a memory object are mutable.</p>
7538
7539<h5>Arguments:</h5>
7540<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7541 The second argument is a constant integer representing the size of the
7542 object, or -1 if it is variable sized and the third argument is a pointer
7543 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7544
7545<h5>Semantics:</h5>
7546<p>This intrinsic indicates that the memory is mutable again.</p>
7547
7548</div>
7549
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7550<!-- ======================================================================= -->
7551<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7552 <a name="int_general">General Intrinsics</a>
7553</div>
7554
7555<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7556
7557<p>This class of intrinsics is designed to be generic and has no specific
7558 purpose.</p>
7559
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7560</div>
7561
7562<!-- _______________________________________________________________________ -->
7563<div class="doc_subsubsection">
7564 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7565</div>
7566
7567<div class="doc_text">
7568
7569<h5>Syntax:</h5>
7570<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7571 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]7572</pre>
7573
7574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7575<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7576
7577<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7578<p>The first argument is a pointer to a value, the second is a pointer to a
7579 global string, the third is a pointer to a global string which is the source
7580 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7581
7582<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7583<p>This intrinsic allows annotation of local variables with arbitrary strings.
7584 This can be useful for special purpose optimizations that want to look for
7585 these annotations. These have no other defined use, they are ignored by code
7586 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7587
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7588</div>
7589
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7590<!-- _______________________________________________________________________ -->
7591<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7592 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7593</div>
7594
7595<div class="doc_text">
7596
7597<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7598<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7599 any integer bit width.</p>
7600
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7601<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7602 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7603 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7604 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7605 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7606 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]7607</pre>
7608
7609<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7610<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7611
7612<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7613<p>The first argument is an integer value (result of some expression), the
7614 second is a pointer to a global string, the third is a pointer to a global
7615 string which is the source file name, and the last argument is the line
7616 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7617
7618<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7619<p>This intrinsic allows annotations to be put on arbitrary expressions with
7620 arbitrary strings. This can be useful for special purpose optimizations that
7621 want to look for these annotations. These have no other defined use, they
7622 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7623
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7624</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7625
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7626<!-- _______________________________________________________________________ -->
7627<div class="doc_subsubsection">
7628 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7629</div>
7630
7631<div class="doc_text">
7632
7633<h5>Syntax:</h5>
7634<pre>
7635 declare void @llvm.trap()
7636</pre>
7637
7638<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7640
7641<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7642<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7643
7644<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7645<p>This intrinsics is lowered to the target dependent trap instruction. If the
7646 target does not have a trap instruction, this intrinsic will be lowered to
7647 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7648
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7649</div>
7650
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7651<!-- _______________________________________________________________________ -->
7652<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7653 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7654</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7655
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7656<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7657
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7658<h5>Syntax:</h5>
7659<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7660 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7662
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7663<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7664<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7665 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7666 ensure that it is placed on the stack before local variables.</p>
7667
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7668<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7669<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7670 arguments. The first argument is the value loaded from the stack
7671 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7672 that has enough space to hold the value of the guard.</p>
7673
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7674<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7675<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7676 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7677 stack. This is to ensure that if a local variable on the stack is
7678 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7679 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7680 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7681 function.</p>
7682
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7683</div>
7684
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7685<!-- _______________________________________________________________________ -->
7686<div class="doc_subsubsection">
7687 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7688</div>
7689
7690<div class="doc_text">
7691
7692<h5>Syntax:</h5>
7693<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7694 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7695 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7696</pre>
7697
7698<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7699<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7700 the optimizers to determine at compile time whether a) an operation (like
7701 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7702 runtime check for overflow isn't necessary. An object in this context means
7703 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7704
7705<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7706<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7707 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7708 is a boolean 0 or 1. This argument determines whether you want the
7709 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]7710 1, variables are not allowed.</p>
7711
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7712<h5>Semantics:</h5>
7713<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7714 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7715 depending on the <tt>type</tt> argument, if the size cannot be determined at
7716 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7717
7718</div>
7719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7720<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7721<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7722<address>
7723 <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]7727
7728 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7729 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7730 Last modified: $Date$
7731</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7732
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7733</body>
7734</html>