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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / f9b2dc66c87256b55f9bdfe037d1fa6f705200e8 / . / 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;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<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
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
886<div class="doc_subsection">
887 <a name="functionstructure">Functions</a>
888</div>
889
890<div class="doc_text">
891
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]919<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]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]928<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]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
935 be significant and two identical functions can be merged</p>.
936
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
949<div class="doc_subsection">
950 <a name="aliasstructure">Aliases</a>
951</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]968<div class="doc_subsection">
969 <a name="namedmetadatastructure">Named Metadata</a>
970</div>
971
972<div class="doc_text">
973
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]991<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]993<div class="doc_text">
994
995<p>The return type and each parameter of a function type may have a set of
996 <i>parameter attributes</i> associated with them. Parameter attributes are
997 used to communicate additional information about the result or parameters of
998 a function. Parameter attributes are considered to be part of the function,
999 not of the function type, so functions with different parameter attributes
1000 can have the same function type.</p>
1001
1002<p>Parameter attributes are simple keywords that follow the type specified. If
1003 multiple parameter attributes are needed, they are space separated. For
1004 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1005
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1007declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1008declare i32 @atoi(i8 zeroext)
1009declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1010</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1013 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1014
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1015<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1020 should be zero-extended to the extent required by the target's ABI (which
1021 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1022 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1023
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1024 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1025 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1026 should be sign-extended to the extent required by the target's ABI (which
1027 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1028 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that this parameter or return value should be treated in a
1032 special target-dependent fashion during while emitting code for a function
1033 call or return (usually, by putting it in a register as opposed to memory,
1034 though some targets use it to distinguish between two different kinds of
1035 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1036
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1037 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1038 <dd><p>This indicates that the pointer parameter should really be passed by
1039 value to the function. The attribute implies that a hidden copy of the
1040 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 is made between the caller and the callee, so the callee is unable to
1042 modify the value in the callee. This attribute is only valid on LLVM
1043 pointer arguments. It is generally used to pass structs and arrays by
1044 value, but is also valid on pointers to scalars. The copy is considered
1045 to belong to the caller not the callee (for example,
1046 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1047 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1048 values.</p>
1049
1050 <p>The byval attribute also supports specifying an alignment with
1051 the align attribute. It indicates the alignment of the stack slot to
1052 form and the known alignment of the pointer specified to the call site. If
1053 the alignment is not specified, then the code generator makes a
1054 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1056 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1057 <dd>This indicates that the pointer parameter specifies the address of a
1058 structure that is the return value of the function in the source program.
1059 This pointer must be guaranteed by the caller to be valid: loads and
1060 stores to the structure may be assumed by the callee to not to trap. This
1061 may only be applied to the first parameter. This is not a valid attribute
1062 for return values. </dd>
1063
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1064 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1065 <dd>This indicates that pointer values
1066 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1067 value do not alias pointer values which are not <i>based</i> on it,
1068 ignoring certain "irrelevant" dependencies.
1069 For a call to the parent function, dependencies between memory
1070 references from before or after the call and from those during the call
1071 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1072 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1073 The caller shares the responsibility with the callee for ensuring that
1074 these requirements are met.
1075 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1076 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1077<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1078 Note that this definition of <tt>noalias</tt> is intentionally
1079 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1080 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1081<br>
1082 For function return values, C99's <tt>restrict</tt> is not meaningful,
1083 while LLVM's <tt>noalias</tt> is.
1084 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1085
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1086 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This indicates that the callee does not make any copies of the pointer
1088 that outlive the callee itself. This is not a valid attribute for return
1089 values.</dd>
1090
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1091 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This indicates that the pointer parameter can be excised using the
1093 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1094 attribute for return values.</dd>
1095</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1096
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1097</div>
1098
1099<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1100<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1101 <a name="gc">Garbage Collector Names</a>
1102</div>
1103
1104<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1106<p>Each function may specify a garbage collector name, which is simply a
1107 string:</p>
1108
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1109<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1110define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1111</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1112
1113<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1114 collector which will cause the compiler to alter its output in order to
1115 support the named garbage collection algorithm.</p>
1116
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1117</div>
1118
1119<!-- ======================================================================= -->
1120<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1121 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122</div>
1123
1124<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1125
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126<p>Function attributes are set to communicate additional information about a
1127 function. Function attributes are considered to be part of the function, not
1128 of the function type, so functions with different parameter attributes can
1129 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1131<p>Function attributes are simple keywords that follow the type specified. If
1132 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1133
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1134<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1135define void @f() noinline { ... }
1136define void @f() alwaysinline { ... }
1137define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1139</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1140
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1141<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1142 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1143 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1144 the backend should forcibly align the stack pointer. Specify the
1145 desired alignment, which must be a power of two, in parentheses.
1146
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This attribute indicates that the inliner should attempt to inline this
1149 function into callers whenever possible, ignoring any active inlining size
1150 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1151
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1152 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1153 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1154 meaning the function can be patched and/or hooked even while it is
1155 loaded into memory. On x86, the function prologue will be preceded
1156 by six bytes of padding and will begin with a two-byte instruction.
1157 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1158 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1159
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1160 <dt><tt><b>inlinehint</b></tt></dt>
1161 <dd>This attribute indicates that the source code contained a hint that inlining
1162 this function is desirable (such as the "inline" keyword in C/C++). It
1163 is just a hint; it imposes no requirements on the inliner.</dd>
1164
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>naked</b></tt></dt>
1166 <dd>This attribute disables prologue / epilogue emission for the function.
1167 This can have very system-specific consequences.</dd>
1168
1169 <dt><tt><b>noimplicitfloat</b></tt></dt>
1170 <dd>This attributes disables implicit floating point instructions.</dd>
1171
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1172 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1173 <dd>This attribute indicates that the inliner should never inline this
1174 function in any situation. This attribute may not be used together with
1175 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1176
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1177 <dt><tt><b>noredzone</b></tt></dt>
1178 <dd>This attribute indicates that the code generator should not use a red
1179 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1180
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This function attribute indicates that the function never returns
1183 normally. This produces undefined behavior at runtime if the function
1184 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1185
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This function attribute indicates that the function never returns with an
1188 unwind or exceptional control flow. If the function does unwind, its
1189 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1190
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1191 <dt><tt><b>optsize</b></tt></dt>
1192 <dd>This attribute suggests that optimization passes and code generator passes
1193 make choices that keep the code size of this function low, and otherwise
1194 do optimizations specifically to reduce code size.</dd>
1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the function computes its result (or decides
1198 to unwind an exception) based strictly on its arguments, without
1199 dereferencing any pointer arguments or otherwise accessing any mutable
1200 state (e.g. memory, control registers, etc) visible to caller functions.
1201 It does not write through any pointer arguments
1202 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1203 changes any state visible to callers. This means that it cannot unwind
1204 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1205 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1206
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute indicates that the function does not write through any
1209 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1210 arguments) or otherwise modify any state (e.g. memory, control registers,
1211 etc) visible to caller functions. It may dereference pointer arguments
1212 and read state that may be set in the caller. A readonly function always
1213 returns the same value (or unwinds an exception identically) when called
1214 with the same set of arguments and global state. It cannot unwind an
1215 exception by calling the <tt>C++</tt> exception throwing methods, but may
1216 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1217
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function should emit a stack smashing
1220 protector. It is in the form of a "canary"&mdash;a random value placed on
1221 the stack before the local variables that's checked upon return from the
1222 function to see if it has been overwritten. A heuristic is used to
1223 determine if a function needs stack protectors or not.<br>
1224<br>
1225 If a function that has an <tt>ssp</tt> attribute is inlined into a
1226 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1227 function will have an <tt>ssp</tt> attribute.</dd>
1228
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This attribute indicates that the function should <em>always</em> emit a
1231 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1232 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1233<br>
1234 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1235 function that doesn't have an <tt>sspreq</tt> attribute or which has
1236 an <tt>ssp</tt> attribute, then the resulting function will have
1237 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1238</dl>
1239
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1240</div>
1241
1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1244 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1245</div>
1246
1247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1250 the GCC "file scope inline asm" blocks. These blocks are internally
1251 concatenated by LLVM and treated as a single unit, but may be separated in
1252 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1253
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1254<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1255module asm "inline asm code goes here"
1256module asm "more can go here"
1257</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1258
1259<p>The strings can contain any character by escaping non-printable characters.
1260 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]1261 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1262
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263<p>The inline asm code is simply printed to the machine code .s file when
1264 assembly code is generated.</p>
1265
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1266</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1267
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="datalayout">Data Layout</a>
1271</div>
1272
1273<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1276 data is to be laid out in memory. The syntax for the data layout is
1277 simply:</p>
1278
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1279<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1280target datalayout = "<i>layout specification</i>"
1281</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282
1283<p>The <i>layout specification</i> consists of a list of specifications
1284 separated by the minus sign character ('-'). Each specification starts with
1285 a letter and may include other information after the letter to define some
1286 aspect of the data layout. The specifications accepted are as follows:</p>
1287
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1288<dl>
1289 <dt><tt>E</tt></dt>
1290 <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]1291 bits with the most significance have the lowest address location.</dd>
1292
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1294 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 the bits with the least significance have the lowest address
1296 location.</dd>
1297
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1298 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1299 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300 <i>preferred</i> alignments. All sizes are in bits. Specifying
1301 the <i>pref</i> alignment is optional. If omitted, the
1302 preceding <tt>:</tt> should be omitted too.</dd>
1303
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1304 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1305 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1306 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1307
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1308 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1309 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1310 <i>size</i>.</dd>
1311
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1313 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1314 <i>size</i>. Only values of <i>size</i> that are supported by the target
1315 will work. 32 (float) and 64 (double) are supported on all targets;
1316 80 or 128 (different flavors of long double) are also supported on some
1317 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1320 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1321 <i>size</i>.</dd>
1322
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1323 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1326
1327 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1328 <dd>This specifies a set of native integer widths for the target CPU
1329 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1330 "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]1331 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1332 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1334
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1335<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1336 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337 specifications in the <tt>datalayout</tt> keyword. The default specifications
1338 are given in this list:</p>
1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340<ul>
1341 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1342 <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]1343 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1344 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1345 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1346 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1347 <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]1348 alignment of 64-bits</li>
1349 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1350 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1351 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1352 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1353 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1354 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1355</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1356
1357<p>When LLVM is determining the alignment for a given type, it uses the
1358 following rules:</p>
1359
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360<ol>
1361 <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]1362 specification is used.</li>
1363
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1364 <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]1365 smallest integer type that is larger than the bitwidth of the sought type
1366 is used. If none of the specifications are larger than the bitwidth then
1367 the the largest integer type is used. For example, given the default
1368 specifications above, the i7 type will use the alignment of i8 (next
1369 largest) while both i65 and i256 will use the alignment of i64 (largest
1370 specified).</li>
1371
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1372 <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]1373 largest vector type that is smaller than the sought vector type will be
1374 used as a fall back. This happens because &lt;128 x double&gt; can be
1375 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1377
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1378</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1379
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1380<!-- ======================================================================= -->
1381<div class="doc_subsection">
1382 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1383</div>
1384
1385<div class="doc_text">
1386
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1387<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1388with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1389is undefined. Pointer values are associated with address ranges
1390according to the following rules:</p>
1391
1392<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1393 <li>A pointer value is associated with the addresses associated with
1394 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1395 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1396 range of the variable's storage.</li>
1397 <li>The result value of an allocation instruction is associated with
1398 the address range of the allocated storage.</li>
1399 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1400 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1401 <li>An integer constant other than zero or a pointer value returned
1402 from a function not defined within LLVM may be associated with address
1403 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1404 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1405 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1406</ul>
1407
1408<p>A pointer value is <i>based</i> on another pointer value according
1409 to the following rules:</p>
1410
1411<ul>
1412 <li>A pointer value formed from a
1413 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1414 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1415 <li>The result value of a
1416 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1417 of the <tt>bitcast</tt>.</li>
1418 <li>A pointer value formed by an
1419 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1420 pointer values that contribute (directly or indirectly) to the
1421 computation of the pointer's value.</li>
1422 <li>The "<i>based</i> on" relationship is transitive.</li>
1423</ul>
1424
1425<p>Note that this definition of <i>"based"</i> is intentionally
1426 similar to the definition of <i>"based"</i> in C99, though it is
1427 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428
1429<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1430<tt><a href="#i_load">load</a></tt> merely indicates the size and
1431alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1432interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1433<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1434and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1435
1436<p>Consequently, type-based alias analysis, aka TBAA, aka
1437<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1438LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1439additional information which specialized optimization passes may use
1440to implement type-based alias analysis.</p>
1441
1442</div>
1443
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1444<!-- ======================================================================= -->
1445<div class="doc_subsection">
1446 <a name="volatile">Volatile Memory Accesses</a>
1447</div>
1448
1449<div class="doc_text">
1450
1451<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1452href="#i_store"><tt>store</tt></a>s, and <a
1453href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1454The optimizers must not change the number of volatile operations or change their
1455order of execution relative to other volatile operations. The optimizers
1456<i>may</i> change the order of volatile operations relative to non-volatile
1457operations. This is not Java's "volatile" and has no cross-thread
1458synchronization behavior.</p>
1459
1460</div>
1461
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1462<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1464<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1466<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1468<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1469 intermediate representation. Being typed enables a number of optimizations
1470 to be performed on the intermediate representation directly, without having
1471 to do extra analyses on the side before the transformation. A strong type
1472 system makes it easier to read the generated code and enables novel analyses
1473 and transformations that are not feasible to perform on normal three address
1474 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1475
1476</div>
1477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1478<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1479<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1480Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1482<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1483
1484<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1485
1486<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1488 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1489 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1490 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1491 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1492 </tr>
1493 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1494 <td><a href="#t_floating">floating point</a></td>
1495 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1496 </tr>
1497 <tr>
1498 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499 <td><a href="#t_integer">integer</a>,
1500 <a href="#t_floating">floating point</a>,
1501 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1502 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1503 <a href="#t_struct">structure</a>,
1504 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1505 <a href="#t_label">label</a>,
1506 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1507 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1508 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 <tr>
1510 <td><a href="#t_primitive">primitive</a></td>
1511 <td><a href="#t_label">label</a>,
1512 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1513 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1514 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1515 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1516 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517 </tr>
1518 <tr>
1519 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1520 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1521 <a href="#t_function">function</a>,
1522 <a href="#t_pointer">pointer</a>,
1523 <a href="#t_struct">structure</a>,
1524 <a href="#t_pstruct">packed structure</a>,
1525 <a href="#t_vector">vector</a>,
1526 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1527 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1528 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1529 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1530</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1531
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1532<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1533 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1534 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1536</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1540
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1541<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1542
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1543<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1544 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1545
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1546</div>
1547
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1548<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1549<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1550
1551<div class="doc_text">
1552
1553<h5>Overview:</h5>
1554<p>The integer type is a very simple type that simply specifies an arbitrary
1555 bit width for the integer type desired. Any bit width from 1 bit to
1556 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1557
1558<h5>Syntax:</h5>
1559<pre>
1560 iN
1561</pre>
1562
1563<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1564 value.</p>
1565
1566<h5>Examples:</h5>
1567<table class="layout">
1568 <tr class="layout">
1569 <td class="left"><tt>i1</tt></td>
1570 <td class="left">a single-bit integer.</td>
1571 </tr>
1572 <tr class="layout">
1573 <td class="left"><tt>i32</tt></td>
1574 <td class="left">a 32-bit integer.</td>
1575 </tr>
1576 <tr class="layout">
1577 <td class="left"><tt>i1942652</tt></td>
1578 <td class="left">a really big integer of over 1 million bits.</td>
1579 </tr>
1580</table>
1581
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1582</div>
1583
1584<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1585<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1586
1587<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1588
1589<table>
1590 <tbody>
1591 <tr><th>Type</th><th>Description</th></tr>
1592 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1593 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1594 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1595 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1596 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1597 </tbody>
1598</table>
1599
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1600</div>
1601
1602<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1603<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1604
1605<div class="doc_text">
1606
1607<h5>Overview:</h5>
1608<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>
1609
1610<h5>Syntax:</h5>
1611<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1612 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1613</pre>
1614
1615</div>
1616
1617<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1618<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1619
1620<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1621
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<h5>Overview:</h5>
1623<p>The void type does not represent any value and has no size.</p>
1624
1625<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626<pre>
1627 void
1628</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1629
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1630</div>
1631
1632<!-- _______________________________________________________________________ -->
1633<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1634
1635<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1636
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1637<h5>Overview:</h5>
1638<p>The label type represents code labels.</p>
1639
1640<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1641<pre>
1642 label
1643</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1644
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1645</div>
1646
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1647<!-- _______________________________________________________________________ -->
1648<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1649
1650<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1651
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1652<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1653<p>The metadata type represents embedded metadata. No derived types may be
1654 created from metadata except for <a href="#t_function">function</a>
1655 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1656
1657<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1658<pre>
1659 metadata
1660</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1661
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1662</div>
1663
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1664
1665<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1669
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1670<p>The real power in LLVM comes from the derived types in the system. This is
1671 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1672 useful types. Each of these types contain one or more element types which
1673 may be a primitive type, or another derived type. For example, it is
1674 possible to have a two dimensional array, using an array as the element type
1675 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1676
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1677
1678</div>
1679
1680<!-- _______________________________________________________________________ -->
1681<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1682
1683<div class="doc_text">
1684
1685<p>Aggregate Types are a subset of derived types that can contain multiple
1686 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1687 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1688 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1689
1690</div>
1691
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1692<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1693<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1695<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1699 sequentially in memory. The array type requires a size (number of elements)
1700 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1701
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1702<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1703<pre>
1704 [&lt;# elements&gt; x &lt;elementtype&gt;]
1705</pre>
1706
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1707<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1708 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1709
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1710<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1711<table class="layout">
1712 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1713 <td class="left"><tt>[40 x i32]</tt></td>
1714 <td class="left">Array of 40 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[41 x i32]</tt></td>
1718 <td class="left">Array of 41 32-bit integer values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>[4 x i8]</tt></td>
1722 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1723 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725<p>Here are some examples of multidimensional arrays:</p>
1726<table class="layout">
1727 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1728 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1729 <td class="left">3x4 array of 32-bit integer values.</td>
1730 </tr>
1731 <tr class="layout">
1732 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1733 <td class="left">12x10 array of single precision floating point values.</td>
1734 </tr>
1735 <tr class="layout">
1736 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1737 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1738 </tr>
1739</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1740
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1741<p>There is no restriction on indexing beyond the end of the array implied by
1742 a static type (though there are restrictions on indexing beyond the bounds
1743 of an allocated object in some cases). This means that single-dimension
1744 'variable sized array' addressing can be implemented in LLVM with a zero
1745 length array type. An implementation of 'pascal style arrays' in LLVM could
1746 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756<p>The function type can be thought of as a function signature. It consists of
1757 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]1758 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1759
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1761<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1762 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1763</pre>
1764
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1765<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]1766 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1767 which indicates that the function takes a variable number of arguments.
1768 Variable argument functions can access their arguments with
1769 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1770 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1771 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1774<table class="layout">
1775 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1776 <td class="left"><tt>i32 (i32)</tt></td>
1777 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1778 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1779 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1780 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1781 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1782 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1783 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1784 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1785 </td>
1786 </tr><tr class="layout">
1787 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1788 <td class="left">A vararg function that takes at least one
1789 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1790 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1791 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1792 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1793 </tr><tr class="layout">
1794 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1795 <td class="left">A function taking an <tt>i32</tt>, returning a
1796 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1797 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1798 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1799</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1801</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1804<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1806<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1809<p>The structure type is used to represent a collection of data members together
1810 in memory. The packing of the field types is defined to match the ABI of the
1811 underlying processor. The elements of a structure may be any type that has a
1812 size.</p>
1813
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1814<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1815 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1816 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1817 Structures in registers are accessed using the
1818 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1819 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1821<pre>
1822 { &lt;type list&gt; }
1823</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1825<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1826<table class="layout">
1827 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1828 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1829 <td class="left">A triple of three <tt>i32</tt> values</td>
1830 </tr><tr class="layout">
1831 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1832 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1833 second element is a <a href="#t_pointer">pointer</a> to a
1834 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1835 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1836 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1839</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1842<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1843</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1844
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1845<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1846
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1847<h5>Overview:</h5>
1848<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1849 together in memory. There is no padding between fields. Further, the
1850 alignment of a packed structure is 1 byte. The elements of a packed
1851 structure may be any type that has a size.</p>
1852
1853<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1854 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1855 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1856
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1857<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1858<pre>
1859 &lt; { &lt;type list&gt; } &gt;
1860</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1861
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1862<h5>Examples:</h5>
1863<table class="layout">
1864 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1865 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1866 <td class="left">A triple of three <tt>i32</tt> values</td>
1867 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1868 <td class="left">
1869<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1870 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1871 second element is a <a href="#t_pointer">pointer</a> to a
1872 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1873 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1874 </tr>
1875</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1876
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1877</div>
1878
1879<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1880<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1881
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1882<div class="doc_text">
1883
1884<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1885<p>The pointer type is used to specify memory locations.
1886 Pointers are commonly used to reference objects in memory.</p>
1887
1888<p>Pointer types may have an optional address space attribute defining the
1889 numbered address space where the pointed-to object resides. The default
1890 address space is number zero. The semantics of non-zero address
1891 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1892
1893<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1894 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1895
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1896<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1897<pre>
1898 &lt;type&gt; *
1899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1900
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1901<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1902<table class="layout">
1903 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1904 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1905 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1906 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1907 </tr>
1908 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1909 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1910 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1911 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1912 <tt>i32</tt>.</td>
1913 </tr>
1914 <tr class="layout">
1915 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1916 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1917 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1918 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1921</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1922
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1924<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1925
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1926<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1927
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1929<p>A vector type is a simple derived type that represents a vector of elements.
1930 Vector types are used when multiple primitive data are operated in parallel
1931 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1932 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1934
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1935<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1936<pre>
1937 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1938</pre>
1939
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1940<p>The number of elements is a constant integer value larger than 0; elementtype
1941 may be any integer or floating point type. Vectors of size zero are not
1942 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1944<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1945<table class="layout">
1946 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1947 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1948 <td class="left">Vector of 4 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1952 <td class="left">Vector of 8 32-bit floating-point values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1956 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1957 </tr>
1958</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1960</div>
1961
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1962<!-- _______________________________________________________________________ -->
1963<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1964<div class="doc_text">
1965
1966<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1968 corresponds (for example) to the C notion of a forward declared structure
1969 type. In LLVM, opaque types can eventually be resolved to any type (not just
1970 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971
1972<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1973<pre>
1974 opaque
1975</pre>
1976
1977<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978<table class="layout">
1979 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1980 <td class="left"><tt>opaque</tt></td>
1981 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1982 </tr>
1983</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1985</div>
1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<!-- ======================================================================= -->
1988<div class="doc_subsection">
1989 <a name="t_uprefs">Type Up-references</a>
1990</div>
1991
1992<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1995<p>An "up reference" allows you to refer to a lexically enclosing type without
1996 requiring it to have a name. For instance, a structure declaration may
1997 contain a pointer to any of the types it is lexically a member of. Example
1998 of up references (with their equivalent as named type declarations)
1999 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000
2001<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2002 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2003 { \2 }* %y = type { %y }*
2004 \1* %z = type %z*
2005</pre>
2006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2007<p>An up reference is needed by the asmprinter for printing out cyclic types
2008 when there is no declared name for a type in the cycle. Because the
2009 asmprinter does not want to print out an infinite type string, it needs a
2010 syntax to handle recursive types that have no names (all names are optional
2011 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Syntax:</h5>
2014<pre>
2015 \&lt;level&gt;
2016</pre>
2017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2018<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2019
2020<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
2023 <td class="left"><tt>\1*</tt></td>
2024 <td class="left">Self-referential pointer.</td>
2025 </tr>
2026 <tr class="layout">
2027 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2028 <td class="left">Recursive structure where the upref refers to the out-most
2029 structure.</td>
2030 </tr>
2031</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2032
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2034
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2035<!-- *********************************************************************** -->
2036<div class="doc_section"> <a name="constants">Constants</a> </div>
2037<!-- *********************************************************************** -->
2038
2039<div class="doc_text">
2040
2041<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043
2044</div>
2045
2046<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2047<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049<div class="doc_text">
2050
2051<dl>
2052 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2054 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2057 <dd>Standard integers (such as '4') are constants of
2058 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2059 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2060
2061 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2062 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2063 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2064 notation (see below). The assembler requires the exact decimal value of a
2065 floating-point constant. For example, the assembler accepts 1.25 but
2066 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2067 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2068
2069 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2070 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2072</dl>
2073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2074<p>The one non-intuitive notation for constants is the hexadecimal form of
2075 floating point constants. For example, the form '<tt>double
2076 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2077 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2078 constants are required (and the only time that they are generated by the
2079 disassembler) is when a floating point constant must be emitted but it cannot
2080 be represented as a decimal floating point number in a reasonable number of
2081 digits. For example, NaN's, infinities, and other special values are
2082 represented in their IEEE hexadecimal format so that assembly and disassembly
2083 do not cause any bits to change in the constants.</p>
2084
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2085<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2086 represented using the 16-digit form shown above (which matches the IEEE754
2087 representation for double); float values must, however, be exactly
2088 representable as IEE754 single precision. Hexadecimal format is always used
2089 for long double, and there are three forms of long double. The 80-bit format
2090 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2091 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2092 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2093 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2094 currently supported target uses this format. Long doubles will only work if
2095 they match the long double format on your target. All hexadecimal formats
2096 are big-endian (sign bit at the left).</p>
2097
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2098<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099</div>
2100
2101<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2102<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2103<a name="aggregateconstants"></a> <!-- old anchor -->
2104<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2105</div>
2106
2107<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2109<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2111
2112<dl>
2113 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2114 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2115 type definitions (a comma separated list of elements, surrounded by braces
2116 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2117 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2118 Structure constants must have <a href="#t_struct">structure type</a>, and
2119 the number and types of elements must match those specified by the
2120 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2121
2122 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2170<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2171@X = global i32 17
2172@Y = global i32 42
2173@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2174</pre>
2175
2176</div>
2177
2178<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2179<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2180<div class="doc_text">
2181
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2182<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]2183 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2184 Undefined values may be of any type (other than '<tt>label</tt>'
2185 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2187<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 program is well defined no matter what value is used. This gives the
2189 compiler more freedom to optimize. Here are some examples of (potentially
2190 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2191
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2192
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2193<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2194 %A = add %X, undef
2195 %B = sub %X, undef
2196 %C = xor %X, undef
2197Safe:
2198 %A = undef
2199 %B = undef
2200 %C = undef
2201</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2202
2203<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]2204 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]2205
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2206<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2207 %A = or %X, undef
2208 %B = and %X, undef
2209Safe:
2210 %A = -1
2211 %B = 0
2212Unsafe:
2213 %A = undef
2214 %B = undef
2215</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2216
2217<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2218 For example, if <tt>%X</tt> has a zero bit, then the output of the
2219 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2220 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2221 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2222 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2223 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2224 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2225 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2226
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2227<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2228 %A = select undef, %X, %Y
2229 %B = select undef, 42, %Y
2230 %C = select %X, %Y, undef
2231Safe:
2232 %A = %X (or %Y)
2233 %B = 42 (or %Y)
2234 %C = %Y
2235Unsafe:
2236 %A = undef
2237 %B = undef
2238 %C = undef
2239</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2240
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2241<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2242 branch) conditions can go <em>either way</em>, but they have to come from one
2243 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2244 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2245 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2246 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2247 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2248 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2250<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2251 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2252
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2253 %B = undef
2254 %C = xor %B, %B
2255
2256 %D = undef
2257 %E = icmp lt %D, 4
2258 %F = icmp gte %D, 4
2259
2260Safe:
2261 %A = undef
2262 %B = undef
2263 %C = undef
2264 %D = undef
2265 %E = undef
2266 %F = undef
2267</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2268
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2269<p>This example points out that two '<tt>undef</tt>' operands are not
2270 necessarily the same. This can be surprising to people (and also matches C
2271 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2272 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2273 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2274 its value over its "live range". This is true because the variable doesn't
2275 actually <em>have a live range</em>. Instead, the value is logically read
2276 from arbitrary registers that happen to be around when needed, so the value
2277 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2278 need to have the same semantics or the core LLVM "replace all uses with"
2279 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2280
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2281<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2282 %A = fdiv undef, %X
2283 %B = fdiv %X, undef
2284Safe:
2285 %A = undef
2286b: unreachable
2287</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2288
2289<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2290 value</em> and <em>undefined behavior</em>. An undefined value (like
2291 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2292 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2293 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2294 defined on SNaN's. However, in the second example, we can make a more
2295 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2296 arbitrary value, we are allowed to assume that it could be zero. Since a
2297 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2298 the operation does not execute at all. This allows us to delete the divide and
2299 all code after it. Because the undefined operation "can't happen", the
2300 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2301
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2302<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2303a: store undef -> %X
2304b: store %X -> undef
2305Safe:
2306a: &lt;deleted&gt;
2307b: unreachable
2308</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2309
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2310<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2311 undefined value can be assumed to not have any effect; we can assume that the
2312 value is overwritten with bits that happen to match what was already there.
2313 However, a store <em>to</em> an undefined location could clobber arbitrary
2314 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2315
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2316</div>
2317
2318<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2319<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2320<div class="doc_text">
2321
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2322<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2323 instead of representing an unspecified bit pattern, they represent the
2324 fact that an instruction or constant expression which cannot evoke side
2325 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2326 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2327
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2328<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]2329 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2330 <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]2331
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2332<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2333
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2334<ul>
2335<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2336 their operands.</li>
2337
2338<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2339 to their dynamic predecessor basic block.</li>
2340
2341<li>Function arguments depend on the corresponding actual argument values in
2342 the dynamic callers of their functions.</li>
2343
2344<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2345 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2346 control back to them.</li>
2347
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2348<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2349 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2350 or exception-throwing call instructions that dynamically transfer control
2351 back to them.</li>
2352
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2353<li>Non-volatile loads and stores depend on the most recent stores to all of the
2354 referenced memory addresses, following the order in the IR
2355 (including loads and stores implied by intrinsics such as
2356 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2357
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2358<!-- TODO: In the case of multiple threads, this only applies if the store
2359 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2361<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2362
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2363<li>An instruction with externally visible side effects depends on the most
2364 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2365 the order in the IR. (This includes
2366 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2367
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2368<li>An instruction <i>control-depends</i> on a
2369 <a href="#terminators">terminator instruction</a>
2370 if the terminator instruction has multiple successors and the instruction
2371 is always executed when control transfers to one of the successors, and
2372 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2373
2374<li>Dependence is transitive.</li>
2375
2376</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2377
2378<p>Whenever a trap value is generated, all values which depend on it evaluate
2379 to trap. If they have side effects, the evoke their side effects as if each
2380 operand with a trap value were undef. If they have externally-visible side
2381 effects, the behavior is undefined.</p>
2382
2383<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2384
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2385<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2386entry:
2387 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2388 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2389 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2390 store i32 0, i32* %trap_yet_again ; undefined behavior
2391
2392 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2393 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2394
2395 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2396
2397 %narrowaddr = bitcast i32* @g to i16*
2398 %wideaddr = bitcast i32* @g to i64*
2399 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2400 %trap4 = load i64* %widaddr ; Returns a trap value.
2401
2402 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2403 %br i1 %cmp, %true, %end ; Branch to either destination.
2404
2405true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2406 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2407 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2408 br label %end
2409
2410end:
2411 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2412 ; Both edges into this PHI are
2413 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2414 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2415
2416 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2417 ; so this is defined (ignoring earlier
2418 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2419</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2420
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2421</div>
2422
2423<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2424<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2425 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2426<div class="doc_text">
2427
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2428<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2429
2430<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2431 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2432 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2433
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2434<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2435 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2436 comparisons against null. Pointer equality tests between labels addresses
2437 results in undefined behavior &mdash; though, again, comparison against null
2438 is ok, and no label is equal to the null pointer. This may be passed around
2439 as an opaque pointer sized value as long as the bits are not inspected. This
2440 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2441 long as the original value is reconstituted before the <tt>indirectbr</tt>
2442 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2443
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2444<p>Finally, some targets may provide defined semantics when using the value as
2445 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2446
2447</div>
2448
2449
2450<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2451<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2452</div>
2453
2454<div class="doc_text">
2455
2456<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 to be used as constants. Constant expressions may be of
2458 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2459 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2460 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2461
2462<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2463 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2464 <dd>Truncate a constant to another type. The bit size of CST must be larger
2465 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2466
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2467 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2468 <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]2469 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2470
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2471 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2472 <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]2473 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2474
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2475 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2476 <dd>Truncate a floating point constant to another floating point type. The
2477 size of CST must be larger than the size of TYPE. Both types must be
2478 floating point.</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>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2481 <dd>Floating point extend a constant to another type. The size of CST must be
2482 smaller or equal to the size of TYPE. Both types must be floating
2483 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2486 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2487 constant. TYPE must be a scalar or vector integer type. CST must be of
2488 scalar or vector floating point type. Both CST and TYPE must be scalars,
2489 or vectors of the same number of elements. If the value won't fit in the
2490 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2491
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2493 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2494 constant. TYPE must be a scalar or vector integer type. CST must be of
2495 scalar or vector floating point type. Both CST and TYPE must be scalars,
2496 or vectors of the same number of elements. If the value won't fit in the
2497 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2499 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2500 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501 constant. TYPE must be a scalar or vector floating point type. CST must be
2502 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2503 vectors of the same number of elements. If the value won't fit in the
2504 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2505
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2507 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2508 constant. TYPE must be a scalar or vector floating point type. CST must be
2509 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2510 vectors of the same number of elements. If the value won't fit in the
2511 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2512
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2513 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2514 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2515 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2516 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2517 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2518
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2521 type. CST must be of integer type. The CST value is zero extended,
2522 truncated, or unchanged to make it fit in a pointer size. This one is
2523 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2524
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2526 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2527 are the same as those for the <a href="#i_bitcast">bitcast
2528 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2529
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2530 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2531 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2532 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2533 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2534 instruction, the index list may have zero or more indexes, which are
2535 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2536
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2538 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2539
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2540 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2541 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2542
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2543 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2544 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2545
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2546 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2547 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2548 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2549
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2550 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2551 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2552 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2553
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2554 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2556 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2557
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2558 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2559 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2560 constants. The index list is interpreted in a similar manner as indices in
2561 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2562 index value must be specified.</dd>
2563
2564 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2565 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2566 constants. The index list is interpreted in a similar manner as indices in
2567 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2568 index value must be specified.</dd>
2569
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2570 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2572 be any of the <a href="#binaryops">binary</a>
2573 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2574 on operands are the same as those for the corresponding instruction
2575 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2576</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2577
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2578</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2580<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2581<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2582<!-- *********************************************************************** -->
2583
2584<!-- ======================================================================= -->
2585<div class="doc_subsection">
2586<a name="inlineasm">Inline Assembler Expressions</a>
2587</div>
2588
2589<div class="doc_text">
2590
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2591<p>LLVM supports inline assembler expressions (as opposed
2592 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2593 a special value. This value represents the inline assembler as a string
2594 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2595 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2596 expression has side effects, and a flag indicating whether the function
2597 containing the asm needs to align its stack conservatively. An example
2598 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2599
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2600<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2601i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2602</pre>
2603
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2604<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2605 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2606 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2607
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2608<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2609%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]2610</pre>
2611
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612<p>Inline asms with side effects not visible in the constraint list must be
2613 marked as having side effects. This is done through the use of the
2614 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2615
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2616<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2617call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2618</pre>
2619
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2620<p>In some cases inline asms will contain code that will not work unless the
2621 stack is aligned in some way, such as calls or SSE instructions on x86,
2622 yet will not contain code that does that alignment within the asm.
2623 The compiler should make conservative assumptions about what the asm might
2624 contain and should generate its usual stack alignment code in the prologue
2625 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2626
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2627<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2628call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2629</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2630
2631<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2632 first.</p>
2633
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2634<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2635 documented here. Constraints on what can be done (e.g. duplication, moving,
2636 etc need to be documented). This is probably best done by reference to
2637 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2638</div>
2639
2640<div class="doc_subsubsection">
2641<a name="inlineasm_md">Inline Asm Metadata</a>
2642</div>
2643
2644<div class="doc_text">
2645
2646<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2647 attached to it that contains a list of constant integers. If present, the
2648 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2649 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2650 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2651 source code that produced it. For example:</p>
2652
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2653<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2654call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2655...
2656!42 = !{ i32 1234567 }
2657</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2658
2659<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2660 IR. If the MDNode contains multiple constants, the code generator will use
2661 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2662
2663</div>
2664
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2665<!-- ======================================================================= -->
2666<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2667 Strings</a>
2668</div>
2669
2670<div class="doc_text">
2671
2672<p>LLVM IR allows metadata to be attached to instructions in the program that
2673 can convey extra information about the code to the optimizers and code
2674 generator. One example application of metadata is source-level debug
2675 information. There are two metadata primitives: strings and nodes. All
2676 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2677 preceding exclamation point ('<tt>!</tt>').</p>
2678
2679<p>A metadata string is a string surrounded by double quotes. It can contain
2680 any character by escaping non-printable characters with "\xx" where "xx" is
2681 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2682
2683<p>Metadata nodes are represented with notation similar to structure constants
2684 (a comma separated list of elements, surrounded by braces and preceded by an
2685 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2686 10}</tt>". Metadata nodes can have any values as their operand.</p>
2687
2688<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2689 metadata nodes, which can be looked up in the module symbol table. For
2690 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2691
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2692<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2693 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2694
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2695<div class="doc_code">
2696<pre>
2697call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2698</pre>
2699</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2700
2701<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2702 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2703
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2704<div class="doc_code">
2705<pre>
2706%indvar.next = add i64 %indvar, 1, !dbg !21
2707</pre>
2708</div>
2709
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2710</div>
2711
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2712
2713<!-- *********************************************************************** -->
2714<div class="doc_section">
2715 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2716</div>
2717<!-- *********************************************************************** -->
2718
2719<p>LLVM has a number of "magic" global variables that contain data that affect
2720code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2721of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2722section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2723by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2724
2725<!-- ======================================================================= -->
2726<div class="doc_subsection">
2727<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2728</div>
2729
2730<div class="doc_text">
2731
2732<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2733href="#linkage_appending">appending linkage</a>. This array contains a list of
2734pointers to global variables and functions which may optionally have a pointer
2735cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2736
2737<pre>
2738 @X = global i8 4
2739 @Y = global i32 123
2740
2741 @llvm.used = appending global [2 x i8*] [
2742 i8* @X,
2743 i8* bitcast (i32* @Y to i8*)
2744 ], section "llvm.metadata"
2745</pre>
2746
2747<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2748compiler, assembler, and linker are required to treat the symbol as if there is
2749a reference to the global that it cannot see. For example, if a variable has
2750internal linkage and no references other than that from the <tt>@llvm.used</tt>
2751list, it cannot be deleted. This is commonly used to represent references from
2752inline asms and other things the compiler cannot "see", and corresponds to
2753"attribute((used))" in GNU C.</p>
2754
2755<p>On some targets, the code generator must emit a directive to the assembler or
2756object file to prevent the assembler and linker from molesting the symbol.</p>
2757
2758</div>
2759
2760<!-- ======================================================================= -->
2761<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2762<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2763</div>
2764
2765<div class="doc_text">
2766
2767<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2768<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2769touching the symbol. On targets that support it, this allows an intelligent
2770linker to optimize references to the symbol without being impeded as it would be
2771by <tt>@llvm.used</tt>.</p>
2772
2773<p>This is a rare construct that should only be used in rare circumstances, and
2774should not be exposed to source languages.</p>
2775
2776</div>
2777
2778<!-- ======================================================================= -->
2779<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2780<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2781</div>
2782
2783<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2784<pre>
2785%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2786@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2787</pre>
2788<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.
2789</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2790
2791</div>
2792
2793<!-- ======================================================================= -->
2794<div class="doc_subsection">
2795<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2796</div>
2797
2798<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2799<pre>
2800%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2801@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2802</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2803
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2804<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.
2805</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2806
2807</div>
2808
2809
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2810<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2811<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2812<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2813
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2814<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2815
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816<p>The LLVM instruction set consists of several different classifications of
2817 instructions: <a href="#terminators">terminator
2818 instructions</a>, <a href="#binaryops">binary instructions</a>,
2819 <a href="#bitwiseops">bitwise binary instructions</a>,
2820 <a href="#memoryops">memory instructions</a>, and
2821 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_subsection"> <a name="terminators">Terminator
2827Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2830
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2831<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2832 in a program ends with a "Terminator" instruction, which indicates which
2833 block should be executed after the current block is finished. These
2834 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2835 control flow, not values (the one exception being the
2836 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2837
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2838<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2839 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2840 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2841 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2842 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2843 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2844 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2845 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2846
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2847</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2849<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2850<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2851Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2852
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2853<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2856<pre>
2857 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]2858 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2859</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2862<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2863 a value) from a function back to the caller.</p>
2864
2865<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2866 value and then causes control flow, and one that just causes control flow to
2867 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2869<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2871 return value. The type of the return value must be a
2872 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2875 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2876 value or a return value with a type that does not match its type, or if it
2877 has a void return type and contains a '<tt>ret</tt>' instruction with a
2878 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2879
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2880<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2881<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2882 the calling function's context. If the caller is a
2883 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2884 instruction after the call. If the caller was an
2885 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2886 the beginning of the "normal" destination block. If the instruction returns
2887 a value, that value shall set the call or invoke instruction's return
2888 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2891<pre>
2892 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2893 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2894 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]2895</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2896
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2897</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2898<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2899<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2901<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2904<pre>
2905 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]2906</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2907
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2908<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2909<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2910 different basic block in the current function. There are two forms of this
2911 instruction, corresponding to a conditional branch and an unconditional
2912 branch.</p>
2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2916 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2917 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2918 target.</p>
2919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2921<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2923 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2924 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2927<pre>
2928Test:
2929 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2930 br i1 %cond, label %IfEqual, label %IfUnequal
2931IfEqual:
2932 <a href="#i_ret">ret</a> i32 1
2933IfUnequal:
2934 <a href="#i_ret">ret</a> i32 0
2935</pre>
2936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2937</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2939<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2940<div class="doc_subsubsection">
2941 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2942</div>
2943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2944<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2945
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2946<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2947<pre>
2948 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2949</pre>
2950
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2951<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2952<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]2953 several different places. It is a generalization of the '<tt>br</tt>'
2954 instruction, allowing a branch to occur to one of many possible
2955 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2958<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2959 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2960 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2961 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2964<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2966 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2967 transferred to the corresponding destination; otherwise, control flow is
2968 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2969
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2970<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2971<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972 <tt>switch</tt> instruction, this instruction may be code generated in
2973 different ways. For example, it could be generated as a series of chained
2974 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2975
2976<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977<pre>
2978 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2979 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2980 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2981
2982 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2983 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2984
2985 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %val, label %otherwise [ i32 0, label %onzero
2987 i32 1, label %onone
2988 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2989</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2991</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2992
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2993
2994<!-- _______________________________________________________________________ -->
2995<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2996 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2997</div>
2998
2999<div class="doc_text">
3000
3001<h5>Syntax:</h5>
3002<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3003 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]3004</pre>
3005
3006<h5>Overview:</h5>
3007
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3008<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3009 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3010 "<tt>address</tt>". Address must be derived from a <a
3011 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3012
3013<h5>Arguments:</h5>
3014
3015<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3016 rest of the arguments indicate the full set of possible destinations that the
3017 address may point to. Blocks are allowed to occur multiple times in the
3018 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3019
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3020<p>This destination list is required so that dataflow analysis has an accurate
3021 understanding of the CFG.</p>
3022
3023<h5>Semantics:</h5>
3024
3025<p>Control transfers to the block specified in the address argument. All
3026 possible destination blocks must be listed in the label list, otherwise this
3027 instruction has undefined behavior. This implies that jumps to labels
3028 defined in other functions have undefined behavior as well.</p>
3029
3030<h5>Implementation:</h5>
3031
3032<p>This is typically implemented with a jump through a register.</p>
3033
3034<h5>Example:</h5>
3035<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3036 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3037</pre>
3038
3039</div>
3040
3041
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3042<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3043<div class="doc_subsubsection">
3044 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3045</div>
3046
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3047<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3048
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3049<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3050<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3051 &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]3052 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3053</pre>
3054
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3055<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3056<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3057 function, with the possibility of control flow transfer to either the
3058 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3059 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3060 control flow will return to the "normal" label. If the callee (or any
3061 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3062 instruction, control is interrupted and continued at the dynamically nearest
3063 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3064
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3065<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3066<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3067
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3068<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3069 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3070 convention</a> the call should use. If none is specified, the call
3071 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3072
3073 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3074 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3075 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3076
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3077 <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]3078 function value being invoked. In most cases, this is a direct function
3079 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3080 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3081
3082 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3084
3085 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3086 signature argument types and parameter attributes. All arguments must be
3087 of <a href="#t_firstclass">first class</a> type. If the function
3088 signature indicates the function accepts a variable number of arguments,
3089 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3092 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3093
3094 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3095 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3097 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3099 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3100</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3101
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3102<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3103<p>This instruction is designed to operate as a standard
3104 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3105 primary difference is that it establishes an association with a label, which
3106 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107
3108<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3110 exception. Additionally, this is important for implementation of
3111 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3113<p>For the purposes of the SSA form, the definition of the value returned by the
3114 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3115 block to the "normal" label. If the callee unwinds then no return value is
3116 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3117
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3118<p>Note that the code generator does not yet completely support unwind, and
3119that the invoke/unwind semantics are likely to change in future versions.</p>
3120
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3121<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3122<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3123 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3124 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3125 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3126 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3127</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3128
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3130
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3131<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3132
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3133<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3134Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3135
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3136<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3137
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3138<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3139<pre>
3140 unwind
3141</pre>
3142
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3143<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3144<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145 at the first callee in the dynamic call stack which used
3146 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3147 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3148
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151 immediately halt. The dynamic call stack is then searched for the
3152 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3153 Once found, execution continues at the "exceptional" destination block
3154 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3155 instruction in the dynamic call chain, undefined behavior results.</p>
3156
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3157<p>Note that the code generator does not yet completely support unwind, and
3158that the invoke/unwind semantics are likely to change in future versions.</p>
3159
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3160</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3161
3162<!-- _______________________________________________________________________ -->
3163
3164<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3165Instruction</a> </div>
3166
3167<div class="doc_text">
3168
3169<h5>Syntax:</h5>
3170<pre>
3171 unreachable
3172</pre>
3173
3174<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3175<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3176 instruction is used to inform the optimizer that a particular portion of the
3177 code is not reachable. This can be used to indicate that the code after a
3178 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3179
3180<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3183</div>
3184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3185<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3186<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3188<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189
3190<p>Binary operators are used to do most of the computation in a program. They
3191 require two operands of the same type, execute an operation on them, and
3192 produce a single value. The operands might represent multiple data, as is
3193 the case with the <a href="#t_vector">vector</a> data type. The result value
3194 has the same type as its operands.</p>
3195
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3196<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3198</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201<div class="doc_subsubsection">
3202 <a name="i_add">'<tt>add</tt>' Instruction</a>
3203</div>
3204
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3205<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3206
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3207<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3208<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3209 &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]3210 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3211 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3212 &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]3213</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3216<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3217
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3218<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219<p>The two arguments to the '<tt>add</tt>' instruction must
3220 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3221 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3223<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3224<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3225
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3226<p>If the sum has unsigned overflow, the result returned is the mathematical
3227 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]3228
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3229<p>Because LLVM integers use a two's complement representation, this instruction
3230 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3231
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3232<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3233 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3234 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3235 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3236 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3238<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239<pre>
3240 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3241</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3243</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3245<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3246<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3247 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3248</div>
3249
3250<div class="doc_text">
3251
3252<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3253<pre>
3254 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3255</pre>
3256
3257<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3258<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3259
3260<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3261<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3263 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3264
3265<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3266<p>The value produced is the floating point sum of the two operands.</p>
3267
3268<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3269<pre>
3270 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3271</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3273</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3277 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3278</div>
3279
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3280<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3281
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3282<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3283<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3284 &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]3285 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3286 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3287 &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]3288</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3290<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3291<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3292 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3293
3294<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3295 '<tt>neg</tt>' instruction present in most other intermediate
3296 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3297
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3298<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3299<p>The two arguments to the '<tt>sub</tt>' instruction must
3300 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3301 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3302
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3303<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3304<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3306<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3307 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3308 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3309
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310<p>Because LLVM integers use a two's complement representation, this instruction
3311 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3312
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3313<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3314 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3315 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3316 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3317 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3319<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3320<pre>
3321 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3322 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3323</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3325</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3327<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3328<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3329 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3330</div>
3331
3332<div class="doc_text">
3333
3334<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3335<pre>
3336 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3337</pre>
3338
3339<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3340<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3341 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3342
3343<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344 '<tt>fneg</tt>' instruction present in most other intermediate
3345 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3346
3347<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3348<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3350 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3351
3352<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3353<p>The value produced is the floating point difference of the two operands.</p>
3354
3355<h5>Example:</h5>
3356<pre>
3357 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3358 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3360
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3361</div>
3362
3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3365 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3366</div>
3367
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3368<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3370<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3372 &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]3373 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3374 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3375 &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]3376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3380
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3381<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3382<p>The two arguments to the '<tt>mul</tt>' instruction must
3383 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3384 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3385
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3386<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3387<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389<p>If the result of the multiplication has unsigned overflow, the result
3390 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3391 width of the result.</p>
3392
3393<p>Because LLVM integers use a two's complement representation, and the result
3394 is the same width as the operands, this instruction returns the correct
3395 result for both signed and unsigned integers. If a full product
3396 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3397 be sign-extended or zero-extended as appropriate to the width of the full
3398 product.</p>
3399
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3400<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3401 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3402 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3403 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3404 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3405
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3406<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3407<pre>
3408 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3409</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3411</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3413<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3414<div class="doc_subsubsection">
3415 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3416</div>
3417
3418<div class="doc_text">
3419
3420<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421<pre>
3422 &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]3423</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3424
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3425<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3427
3428<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3429<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3431 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3432
3433<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3434<p>The value produced is the floating point product of the two operands.</p>
3435
3436<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3437<pre>
3438 &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]3439</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3441</div>
3442
3443<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3444<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3445</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3447<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3448
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3449<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3451 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3452 &lt;result&gt; = udiv 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]3453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3457
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3459<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3461 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3464<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3465
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3466<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3468
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3469<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3471<p>If the <tt>exact</tt> keyword is present, the result value of the
3472 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3473 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3474
3475
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3479</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3481</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3485</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3491 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3492 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3493</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3497
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3499<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3501 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504<p>The value produced is the signed integer quotient of the two operands rounded
3505 towards zero.</p>
3506
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3507<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3509
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3510<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511 undefined behavior; this is a rare case, but can occur, for example, by doing
3512 a 32-bit division of -2147483648 by -1.</p>
3513
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3514<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3515 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3516 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3517
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3521</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3523</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3527Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3529<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3532<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3533 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3534</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536<h5>Overview:</h5>
3537<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3538
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3540<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3542 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3545<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548<pre>
3549 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3552</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3554<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3555<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3556</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3558<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3565<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3567 division of its two arguments.</p>
3568
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3570<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3572 values. Both arguments must have identical types.</p>
3573
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576 This instruction always performs an unsigned division to get the
3577 remainder.</p>
3578
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3579<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3581
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3582<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3584<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585<pre>
3586 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3587</pre>
3588
3589</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3594</div>
3595
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3600 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3605 division of its two operands. This instruction can also take
3606 <a href="#t_vector">vector</a> versions of the values in which case the
3607 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3608
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3609<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3610<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3612 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3613
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3614<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3615<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3616 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3617 <i>modulo</i> operator (where the result is either zero or has the same sign
3618 as the divisor, <tt>op2</tt>) of a value.
3619 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3621 Math Forum</a>. For a table of how this is implemented in various languages,
3622 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3623 Wikipedia: modulo operation</a>.</p>
3624
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3625<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3626 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3627
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3628<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629 Overflow also leads to undefined behavior; this is a rare case, but can
3630 occur, for example, by taking the remainder of a 32-bit division of
3631 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3632 lets srem be implemented using instructions that return both the result of
3633 the division and the remainder.)</p>
3634
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636<pre>
3637 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3638</pre>
3639
3640</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3642<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3643<div class="doc_subsubsection">
3644 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3645
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3646<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3647
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3648<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649<pre>
3650 &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]3651</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3652
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3653<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3654<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3655 its two operands.</p>
3656
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3657<h5>Arguments:</h5>
3658<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3660 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3661
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3662<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663<p>This instruction returns the <i>remainder</i> of a division. The remainder
3664 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3665
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3666<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3667<pre>
3668 &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]3669</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3671</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3672
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3673<!-- ======================================================================= -->
3674<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3675Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3676
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3677<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678
3679<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3680 program. They are generally very efficient instructions and can commonly be
3681 strength reduced from other instructions. They require two operands of the
3682 same type, execute an operation on them, and produce a single value. The
3683 resulting value is the same type as its operands.</p>
3684
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3685</div>
3686
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3687<!-- _______________________________________________________________________ -->
3688<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3689Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3691<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3693<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3695 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3696 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3697 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3698 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3699</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3702<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3703 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3704
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3705<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3707 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3708 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3709
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3710<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3712 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3713 is (statically or dynamically) negative or equal to or larger than the number
3714 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3715 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3716 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3717
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3718<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3719 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]3720 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3721 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3722 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3723 they would if the shift were expressed as a mul instruction with the same
3724 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3725
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726<h5>Example:</h5>
3727<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3728 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3729 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3730 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3731 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3732 &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]3733</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3734
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3735</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3739Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3741<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3743<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3745 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3746 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3747</pre>
3748
3749<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3751 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3754<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3755 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3756 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3757
3758<h5>Semantics:</h5>
3759<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3760 significant bits of the result will be filled with zero bits after the shift.
3761 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3762 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3763 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3764 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3765
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3766<p>If the <tt>exact</tt> keyword is present, the result value of the
3767 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3768 shifted out are non-zero.</p>
3769
3770
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3771<h5>Example:</h5>
3772<pre>
3773 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3774 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3775 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3776 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3777 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3778 &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]3779</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3780
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3781</div>
3782
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3783<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3784<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3785Instruction</a> </div>
3786<div class="doc_text">
3787
3788<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3790 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3791 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3792</pre>
3793
3794<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3795<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3796 operand shifted to the right a specified number of bits with sign
3797 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3798
3799<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3800<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3801 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3802 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3803
3804<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805<p>This instruction always performs an arithmetic shift right operation, The
3806 most significant bits of the result will be filled with the sign bit
3807 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3808 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3809 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3810 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3811
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3812<p>If the <tt>exact</tt> keyword is present, the result value of the
3813 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3814 shifted out are non-zero.</p>
3815
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3816<h5>Example:</h5>
3817<pre>
3818 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3819 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3820 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3821 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3822 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3823 &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]3824</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3826</div>
3827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3828<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3829<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3830Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3831
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3832<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3834<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3835<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3836 &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]3837</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3839<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3841 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3843<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3844<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3846 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3849<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3851<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3852 <tbody>
3853 <tr>
3854 <td>In0</td>
3855 <td>In1</td>
3856 <td>Out</td>
3857 </tr>
3858 <tr>
3859 <td>0</td>
3860 <td>0</td>
3861 <td>0</td>
3862 </tr>
3863 <tr>
3864 <td>0</td>
3865 <td>1</td>
3866 <td>0</td>
3867 </tr>
3868 <tr>
3869 <td>1</td>
3870 <td>0</td>
3871 <td>0</td>
3872 </tr>
3873 <tr>
3874 <td>1</td>
3875 <td>1</td>
3876 <td>1</td>
3877 </tr>
3878 </tbody>
3879</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3881<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3882<pre>
3883 &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]3884 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3885 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3886</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3887</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3888<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3889<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3890
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3891<div class="doc_text">
3892
3893<h5>Syntax:</h5>
3894<pre>
3895 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3896</pre>
3897
3898<h5>Overview:</h5>
3899<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3900 two operands.</p>
3901
3902<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3903<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3904 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3905 values. Both arguments must have identical types.</p>
3906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3908<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3910<table border="1" cellspacing="0" cellpadding="4">
3911 <tbody>
3912 <tr>
3913 <td>In0</td>
3914 <td>In1</td>
3915 <td>Out</td>
3916 </tr>
3917 <tr>
3918 <td>0</td>
3919 <td>0</td>
3920 <td>0</td>
3921 </tr>
3922 <tr>
3923 <td>0</td>
3924 <td>1</td>
3925 <td>1</td>
3926 </tr>
3927 <tr>
3928 <td>1</td>
3929 <td>0</td>
3930 <td>1</td>
3931 </tr>
3932 <tr>
3933 <td>1</td>
3934 <td>1</td>
3935 <td>1</td>
3936 </tr>
3937 </tbody>
3938</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3940<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3941<pre>
3942 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3943 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3944 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3945</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3947</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3949<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3950<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3951Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3954
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3955<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3956<pre>
3957 &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]3958</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3960<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3962 its two operands. The <tt>xor</tt> is used to implement the "one's
3963 complement" operation, which is the "~" operator in C.</p>
3964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3965<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3966<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3968 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3970<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3971<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3973<table border="1" cellspacing="0" cellpadding="4">
3974 <tbody>
3975 <tr>
3976 <td>In0</td>
3977 <td>In1</td>
3978 <td>Out</td>
3979 </tr>
3980 <tr>
3981 <td>0</td>
3982 <td>0</td>
3983 <td>0</td>
3984 </tr>
3985 <tr>
3986 <td>0</td>
3987 <td>1</td>
3988 <td>1</td>
3989 </tr>
3990 <tr>
3991 <td>1</td>
3992 <td>0</td>
3993 <td>1</td>
3994 </tr>
3995 <tr>
3996 <td>1</td>
3997 <td>1</td>
3998 <td>0</td>
3999 </tr>
4000 </tbody>
4001</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4003<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4004<pre>
4005 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4006 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4007 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4008 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4009</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4011</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4013<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4014<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4015 <a name="vectorops">Vector Operations</a>
4016</div>
4017
4018<div class="doc_text">
4019
4020<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021 target-independent manner. These instructions cover the element-access and
4022 vector-specific operations needed to process vectors effectively. While LLVM
4023 does directly support these vector operations, many sophisticated algorithms
4024 will want to use target-specific intrinsics to take full advantage of a
4025 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4026
4027</div>
4028
4029<!-- _______________________________________________________________________ -->
4030<div class="doc_subsubsection">
4031 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4032</div>
4033
4034<div class="doc_text">
4035
4036<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4037<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4038 &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]4039</pre>
4040
4041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4043 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4044
4045
4046<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4047<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4048 of <a href="#t_vector">vector</a> type. The second operand is an index
4049 indicating the position from which to extract the element. The index may be
4050 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4051
4052<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4053<p>The result is a scalar of the same type as the element type of
4054 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4055 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4056 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4059<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4060 &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]4061</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<!-- _______________________________________________________________________ -->
4066<div class="doc_subsubsection">
4067 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4068</div>
4069
4070<div class="doc_text">
4071
4072<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4073<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4074 &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]4075</pre>
4076
4077<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4079 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4080
4081<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4082<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4083 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4084 whose type must equal the element type of the first operand. The third
4085 operand is an index indicating the position at which to insert the value.
4086 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4087
4088<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4089<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4090 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4091 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4092 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4093
4094<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4095<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4096 &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]4097</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4099</div>
4100
4101<!-- _______________________________________________________________________ -->
4102<div class="doc_subsubsection">
4103 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4104</div>
4105
4106<div class="doc_text">
4107
4108<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4109<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4110 &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]4111</pre>
4112
4113<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4114<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4115 from two input vectors, returning a vector with the same element type as the
4116 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4117
4118<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4120 with types that match each other. The third argument is a shuffle mask whose
4121 element type is always 'i32'. The result of the instruction is a vector
4122 whose length is the same as the shuffle mask and whose element type is the
4123 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4124
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4125<p>The shuffle mask operand is required to be a constant vector with either
4126 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4127
4128<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129<p>The elements of the two input vectors are numbered from left to right across
4130 both of the vectors. The shuffle mask operand specifies, for each element of
4131 the result vector, which element of the two input vectors the result element
4132 gets. The element selector may be undef (meaning "don't care") and the
4133 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4134
4135<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4136<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4137 &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]4138 &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]4139 &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]4140 &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]4141 &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]4142 &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]4143 &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]4144 &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]4145</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4146
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4147</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4148
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4149<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4150<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4151 <a name="aggregateops">Aggregate Operations</a>
4152</div>
4153
4154<div class="doc_text">
4155
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4156<p>LLVM supports several instructions for working with
4157 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4158
4159</div>
4160
4161<!-- _______________________________________________________________________ -->
4162<div class="doc_subsubsection">
4163 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4164</div>
4165
4166<div class="doc_text">
4167
4168<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4169<pre>
4170 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4171</pre>
4172
4173<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4174<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4175 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4176
4177<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4179 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4180 <a href="#t_array">array</a> type. The operands are constant indices to
4181 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4183 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4184 <ul>
4185 <li>Since the value being indexed is not a pointer, the first index is
4186 omitted and assumed to be zero.</li>
4187 <li>At least one index must be specified.</li>
4188 <li>Not only struct indices but also array indices must be in
4189 bounds.</li>
4190 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4191
4192<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4193<p>The result is the value at the position in the aggregate specified by the
4194 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4195
4196<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4198 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4199</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4200
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4201</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4202
4203<!-- _______________________________________________________________________ -->
4204<div class="doc_subsubsection">
4205 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4206</div>
4207
4208<div class="doc_text">
4209
4210<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4211<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4212 &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]4213</pre>
4214
4215<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4216<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4217 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4218
4219<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4220<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4221 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4222 <a href="#t_array">array</a> type. The second operand is a first-class
4223 value to insert. The following operands are constant indices indicating
4224 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4225 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4226 value to insert must have the same type as the value identified by the
4227 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4228
4229<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4231 that of <tt>val</tt> except that the value at the position specified by the
4232 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4233
4234<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4235<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4236 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4237 %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]4238</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4239
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4240</div>
4241
4242
4243<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4244<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4245 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4246</div>
4247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4248<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4249
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250<p>A key design point of an SSA-based representation is how it represents
4251 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4252 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4253 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4255</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4257<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4258<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4259 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4260</div>
4261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4262<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4265<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4266 &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]4267</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4268
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4269<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4270<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 currently executing function, to be automatically released when this function
4272 returns to its caller. The object is always allocated in the generic address
4273 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4276<p>The '<tt>alloca</tt>' instruction
4277 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4278 runtime stack, returning a pointer of the appropriate type to the program.
4279 If "NumElements" is specified, it is the number of elements allocated,
4280 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4281 specified, the value result of the allocation is guaranteed to be aligned to
4282 at least that boundary. If not specified, or if zero, the target can choose
4283 to align the allocation on any convenient boundary compatible with the
4284 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4286<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4288<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4289<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4290 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4291 memory is automatically released when the function returns. The
4292 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4293 variables that must have an address available. When the function returns
4294 (either with the <tt><a href="#i_ret">ret</a></tt>
4295 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4296 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4297
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4298<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4299<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4300 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4301 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4302 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4303 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4304</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4306</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4307
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4308<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4309<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4310Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4312<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4316 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4317 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4318 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319</pre>
4320
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4321<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4322<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4324<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4326 from which to load. The pointer must point to
4327 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4328 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4329 number or order of execution of this <tt>load</tt> with other <a
4330 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4332<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333 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]4334 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335 alignment for the target. It is the responsibility of the code emitter to
4336 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4337 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338 produce less efficient code. An alignment of 1 is always safe.</p>
4339
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4340<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4341 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4342 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4343 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4344 and code generator that this load is not expected to be reused in the cache.
4345 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4346 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4347
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4348<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349<p>The location of memory pointed to is loaded. If the value being loaded is of
4350 scalar type then the number of bytes read does not exceed the minimum number
4351 of bytes needed to hold all bits of the type. For example, loading an
4352 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4353 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4354 is undefined if the value was not originally written using a store of the
4355 same type.</p>
4356
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4357<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358<pre>
4359 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4360 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4361 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4362</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4363
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4364</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4365
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4366<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4367<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4368Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4370<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4371
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4372<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4373<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4374 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>
4375 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]4376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4378<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4379<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4380
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4381<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4382<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4383 and an address at which to store it. The type of the
4384 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4385 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4386 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4387 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4388 order of execution of this <tt>store</tt> with other <a
4389 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4390
4391<p>The optional constant "align" argument specifies the alignment of the
4392 operation (that is, the alignment of the memory address). A value of 0 or an
4393 omitted "align" argument means that the operation has the preferential
4394 alignment for the target. It is the responsibility of the code emitter to
4395 ensure that the alignment information is correct. Overestimating the
4396 alignment results in an undefined behavior. Underestimating the alignment may
4397 produce less efficient code. An alignment of 1 is always safe.</p>
4398
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4399<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4400 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4401 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4402 instruction tells the optimizer and code generator that this load is
4403 not expected to be reused in the cache. The code generator may
4404 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4405 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4406
4407
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4408<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4409<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4410 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4411 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4412 does not exceed the minimum number of bytes needed to hold all bits of the
4413 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4414 writing a value of a type like <tt>i20</tt> with a size that is not an
4415 integral number of bytes, it is unspecified what happens to the extra bits
4416 that do not belong to the type, but they will typically be overwritten.</p>
4417
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4418<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4419<pre>
4420 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4421 store i32 3, i32* %ptr <i>; yields {void}</i>
4422 %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]4423</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4425</div>
4426
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4427<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4428<div class="doc_subsubsection">
4429 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4430</div>
4431
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4432<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4434<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4435<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4436 &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]4437 &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]4438</pre>
4439
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4442 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4443 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4444
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4445<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4446<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4447 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4448 elements of the aggregate object are indexed. The interpretation of each
4449 index is dependent on the type being indexed into. The first index always
4450 indexes the pointer value given as the first argument, the second index
4451 indexes a value of the type pointed to (not necessarily the value directly
4452 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4453 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4454 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4455 can never be pointers, since that would require loading the pointer before
4456 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4457
4458<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]4459 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4460 integer <b>constants</b> are allowed. When indexing into an array, pointer
4461 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]4462 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4464<p>For example, let's consider a C code fragment and how it gets compiled to
4465 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4466
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4467<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4468struct RT {
4469 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4470 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4471 char C;
4472};
4473struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4474 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4475 double Y;
4476 struct RT Z;
4477};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4478
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4479int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4480 return &amp;s[1].Z.B[5][13];
4481}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4482</pre>
4483
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4484<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4485
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4486<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4487%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4488%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4490define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4491entry:
4492 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4493 ret i32* %reg
4494}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4495</pre>
4496
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4497<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4498<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]4499 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4500 }</tt>' type, a structure. The second index indexes into the third element
4501 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4502 i8 }</tt>' type, another structure. The third index indexes into the second
4503 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4504 array. The two dimensions of the array are subscripted into, yielding an
4505 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4506 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4508<p>Note that it is perfectly legal to index partially through a structure,
4509 returning a pointer to an inner element. Because of this, the LLVM code for
4510 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4511
4512<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4513 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4514 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4515 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4516 %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]4517 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4518 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4519 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4520 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4521</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4522
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4523<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4524 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4525 base pointer is not an <i>in bounds</i> address of an allocated object,
4526 or if any of the addresses that would be formed by successive addition of
4527 the offsets implied by the indices to the base address with infinitely
4528 precise arithmetic are not an <i>in bounds</i> address of that allocated
4529 object. The <i>in bounds</i> addresses for an allocated object are all
4530 the addresses that point into the object, plus the address one byte past
4531 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4532
4533<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4534 the base address with silently-wrapping two's complement arithmetic, and
4535 the result value of the <tt>getelementptr</tt> may be outside the object
4536 pointed to by the base pointer. The result value may not necessarily be
4537 used to access memory though, even if it happens to point into allocated
4538 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4539 section for more information.</p>
4540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4541<p>The getelementptr instruction is often confusing. For some more insight into
4542 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4543
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4544<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4545<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4546 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4547 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4548 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4549 %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]4550 <i>; yields i8*:eptr</i>
4551 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4552 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4553 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4554</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4555
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4556</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4558<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4559<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4560</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4562<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4563
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4564<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4565 which all take a single operand and a type. They perform various bit
4566 conversions on the operand.</p>
4567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4568</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4569
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4570<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4571<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4572 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4573</div>
4574<div class="doc_text">
4575
4576<h5>Syntax:</h5>
4577<pre>
4578 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4579</pre>
4580
4581<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4582<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4583 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4584
4585<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4586<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
4587 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4588 of the same number of integers.
4589 The bit size of the <tt>value</tt> must be larger than
4590 the bit size of the destination type, <tt>ty2</tt>.
4591 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4594<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4595 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4596 source size must be larger than the destination size, <tt>trunc</tt> cannot
4597 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4598
4599<h5>Example:</h5>
4600<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4601 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4602 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4603 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
4604 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4605</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4607</div>
4608
4609<!-- _______________________________________________________________________ -->
4610<div class="doc_subsubsection">
4611 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4612</div>
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
4616<pre>
4617 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4618</pre>
4619
4620<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4621<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4622 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4623
4624
4625<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]4626<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
4627 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4628 of the same number of integers.
4629 The bit size of the <tt>value</tt> must be smaller than
4630 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4632
4633<h5>Semantics:</h5>
4634<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]4635 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4636
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4637<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]4638
4639<h5>Example:</h5>
4640<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4641 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4642 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]4643 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4644</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4646</div>
4647
4648<!-- _______________________________________________________________________ -->
4649<div class="doc_subsubsection">
4650 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4651</div>
4652<div class="doc_text">
4653
4654<h5>Syntax:</h5>
4655<pre>
4656 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4657</pre>
4658
4659<h5>Overview:</h5>
4660<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4661
4662<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4663<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
4664 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4665 of the same number of integers.
4666 The bit size of the <tt>value</tt> must be smaller than
4667 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4668 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4669
4670<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4672 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4673 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4674
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4675<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]4676
4677<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4678<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4679 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4680 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4681 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4682</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4683
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4684</div>
4685
4686<!-- _______________________________________________________________________ -->
4687<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4688 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4689</div>
4690
4691<div class="doc_text">
4692
4693<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4694<pre>
4695 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4696</pre>
4697
4698<h5>Overview:</h5>
4699<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4700 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4701
4702<h5>Arguments:</h5>
4703<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4704 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4705 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]4706 <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]4707 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4708
4709<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4711 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712 <a href="#t_floating">floating point</a> type. If the value cannot fit
4713 within the destination type, <tt>ty2</tt>, then the results are
4714 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4715
4716<h5>Example:</h5>
4717<pre>
4718 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4719 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4720</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4722</div>
4723
4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4726 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4727</div>
4728<div class="doc_text">
4729
4730<h5>Syntax:</h5>
4731<pre>
4732 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4733</pre>
4734
4735<h5>Overview:</h5>
4736<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]4737 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4740<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4742 a <a href="#t_floating">floating point</a> type to cast it to. The source
4743 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4744
4745<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4746<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4747 <a href="#t_floating">floating point</a> type to a larger
4748 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4749 used to make a <i>no-op cast</i> because it always changes bits. Use
4750 <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]4751
4752<h5>Example:</h5>
4753<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]4754 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
4755 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4756</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4757
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4758</div>
4759
4760<!-- _______________________________________________________________________ -->
4761<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4762 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764<div class="doc_text">
4765
4766<h5>Syntax:</h5>
4767<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4768 &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]4769</pre>
4770
4771<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4772<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4774
4775<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4777 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4778 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4779 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4780 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4781
4782<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4783<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4784 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4785 towards zero) unsigned integer value. If the value cannot fit
4786 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4787
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4788<h5>Example:</h5>
4789<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4790 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4791 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4792 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4793</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4794
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4795</div>
4796
4797<!-- _______________________________________________________________________ -->
4798<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4799 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800</div>
4801<div class="doc_text">
4802
4803<h5>Syntax:</h5>
4804<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4805 &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]4806</pre>
4807
4808<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4809<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4810 <a href="#t_floating">floating point</a> <tt>value</tt> to
4811 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4812
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4813<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4814<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4815 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4816 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4817 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4818 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4819
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4820<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4821<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4822 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4823 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4824 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4825
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4826<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4827<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4828 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4829 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4830 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4831</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4832
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4833</div>
4834
4835<!-- _______________________________________________________________________ -->
4836<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4837 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4838</div>
4839<div class="doc_text">
4840
4841<h5>Syntax:</h5>
4842<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4843 &lt;result&gt; = 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]4844</pre>
4845
4846<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4847<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4849
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4850<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4851<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]4852 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4853 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4854 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4855 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4856
4857<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4858<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4859 integer quantity and converts it to the corresponding floating point
4860 value. If the value cannot fit in the floating point value, the results are
4861 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4862
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4863<h5>Example:</h5>
4864<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4865 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4866 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4868
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4869</div>
4870
4871<!-- _______________________________________________________________________ -->
4872<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4873 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4874</div>
4875<div class="doc_text">
4876
4877<h5>Syntax:</h5>
4878<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4879 &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]4880</pre>
4881
4882<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4884 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4885
4886<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4887<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]4888 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4889 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4890 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4891 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4892
4893<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4895 quantity and converts it to the corresponding floating point value. If the
4896 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4897
4898<h5>Example:</h5>
4899<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4900 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4901 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4902</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4904</div>
4905
4906<!-- _______________________________________________________________________ -->
4907<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4908 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4909</div>
4910<div class="doc_text">
4911
4912<h5>Syntax:</h5>
4913<pre>
4914 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4915</pre>
4916
4917<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4918<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4919 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4920
4921<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4922<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4923 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4924 <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]4925
4926<h5>Semantics:</h5>
4927<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4928 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4929 truncating or zero extending that value to the size of the integer type. If
4930 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4931 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4932 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4933 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4934
4935<h5>Example:</h5>
4936<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4937 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4938 %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]4939</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4940
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4941</div>
4942
4943<!-- _______________________________________________________________________ -->
4944<div class="doc_subsubsection">
4945 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4946</div>
4947<div class="doc_text">
4948
4949<h5>Syntax:</h5>
4950<pre>
4951 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4952</pre>
4953
4954<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4956 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4957
4958<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4959<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960 value to cast, and a type to cast it to, which must be a
4961 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4962
4963<h5>Semantics:</h5>
4964<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4966 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4967 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4968 than the size of a pointer then a zero extension is done. If they are the
4969 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4970
4971<h5>Example:</h5>
4972<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4973 %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]4974 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4975 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4976</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4977
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4978</div>
4979
4980<!-- _______________________________________________________________________ -->
4981<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4982 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4983</div>
4984<div class="doc_text">
4985
4986<h5>Syntax:</h5>
4987<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4988 &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]4989</pre>
4990
4991<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4992<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4993 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4994
4995<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4997 non-aggregate first class value, and a type to cast it to, which must also be
4998 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4999 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5000 identical. If the source type is a pointer, the destination type must also be
5001 a pointer. This instruction supports bitwise conversion of vectors to
5002 integers and to vectors of other types (as long as they have the same
5003 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5004
5005<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5006<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5007 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5008 this conversion. The conversion is done as if the <tt>value</tt> had been
5009 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5010 be converted to other pointer types with this instruction. To convert
5011 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5012 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5013
5014<h5>Example:</h5>
5015<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5016 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5017 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5018 %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]5019</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5020
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5021</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5022
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5023<!-- ======================================================================= -->
5024<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5026<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027
5028<p>The instructions in this category are the "miscellaneous" instructions, which
5029 defy better classification.</p>
5030
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5031</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5032
5033<!-- _______________________________________________________________________ -->
5034<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5035</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5037<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040<pre>
5041 &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]5042</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5046 boolean values based on comparison of its two integer, integer vector, or
5047 pointer operands.</p>
5048
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5049<h5>Arguments:</h5>
5050<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051 the condition code indicating the kind of comparison to perform. It is not a
5052 value, just a keyword. The possible condition code are:</p>
5053
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5054<ol>
5055 <li><tt>eq</tt>: equal</li>
5056 <li><tt>ne</tt>: not equal </li>
5057 <li><tt>ugt</tt>: unsigned greater than</li>
5058 <li><tt>uge</tt>: unsigned greater or equal</li>
5059 <li><tt>ult</tt>: unsigned less than</li>
5060 <li><tt>ule</tt>: unsigned less or equal</li>
5061 <li><tt>sgt</tt>: signed greater than</li>
5062 <li><tt>sge</tt>: signed greater or equal</li>
5063 <li><tt>slt</tt>: signed less than</li>
5064 <li><tt>sle</tt>: signed less or equal</li>
5065</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5067<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5069 typed. They must also be identical types.</p>
5070
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5071<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5072<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5073 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5074 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]5075 result, as follows:</p>
5076
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5077<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5078 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5079 <tt>false</tt> otherwise. No sign interpretation is necessary or
5080 performed.</li>
5081
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5082 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5083 <tt>false</tt> otherwise. No sign interpretation is necessary or
5084 performed.</li>
5085
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5086 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5087 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5088
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5089 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5090 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5091 to <tt>op2</tt>.</li>
5092
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5093 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5094 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5096 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5098
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5099 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5100 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5101
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5102 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5103 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5104 to <tt>op2</tt>.</li>
5105
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5106 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5107 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5108
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5109 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110 <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]5111</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5113<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5114 values are compared as if they were integers.</p>
5115
5116<p>If the operands are integer vectors, then they are compared element by
5117 element. The result is an <tt>i1</tt> vector with the same number of elements
5118 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5119
5120<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5121<pre>
5122 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5123 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5124 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5125 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5126 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5127 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5128</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5129
5130<p>Note that the code generator does not yet support vector types with
5131 the <tt>icmp</tt> instruction.</p>
5132
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133</div>
5134
5135<!-- _______________________________________________________________________ -->
5136<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5137</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5138
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5139<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5140
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5141<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5142<pre>
5143 &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]5144</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5145
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5146<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5147<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5148 values based on comparison of its operands.</p>
5149
5150<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]5151(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152
5153<p>If the operands are floating point vectors, then the result type is a vector
5154 of boolean with the same number of elements as the operands being
5155 compared.</p>
5156
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5157<h5>Arguments:</h5>
5158<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5159 the condition code indicating the kind of comparison to perform. It is not a
5160 value, just a keyword. The possible condition code are:</p>
5161
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5162<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5163 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5164 <li><tt>oeq</tt>: ordered and equal</li>
5165 <li><tt>ogt</tt>: ordered and greater than </li>
5166 <li><tt>oge</tt>: ordered and greater than or equal</li>
5167 <li><tt>olt</tt>: ordered and less than </li>
5168 <li><tt>ole</tt>: ordered and less than or equal</li>
5169 <li><tt>one</tt>: ordered and not equal</li>
5170 <li><tt>ord</tt>: ordered (no nans)</li>
5171 <li><tt>ueq</tt>: unordered or equal</li>
5172 <li><tt>ugt</tt>: unordered or greater than </li>
5173 <li><tt>uge</tt>: unordered or greater than or equal</li>
5174 <li><tt>ult</tt>: unordered or less than </li>
5175 <li><tt>ule</tt>: unordered or less than or equal</li>
5176 <li><tt>une</tt>: unordered or not equal</li>
5177 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5178 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5179</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5180
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5181<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5182 <i>unordered</i> means that either operand may be a QNAN.</p>
5183
5184<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5185 a <a href="#t_floating">floating point</a> type or
5186 a <a href="#t_vector">vector</a> of floating point type. They must have
5187 identical types.</p>
5188
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5189<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5190<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5191 according to the condition code given as <tt>cond</tt>. If the operands are
5192 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5193 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5194 follows:</p>
5195
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5196<ol>
5197 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5198
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5199 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5201
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5204
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5205 <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]5206 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5207
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5210
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5211 <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]5212 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5213
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5214 <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]5215 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5216
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5217 <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]5218
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5221
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5224
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5227
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5228 <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]5229 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5230
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5231 <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]5232 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5233
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5234 <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]5235 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5236
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5237 <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]5238
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5239 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5240</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5241
5242<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5243<pre>
5244 &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]5245 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5246 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5247 &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]5248</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5249
5250<p>Note that the code generator does not yet support vector types with
5251 the <tt>fcmp</tt> instruction.</p>
5252
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5253</div>
5254
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5255<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5256<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5257 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5258</div>
5259
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5260<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5261
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5262<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5263<pre>
5264 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5265</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5266
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5267<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5269 SSA graph representing the function.</p>
5270
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5271<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5272<p>The type of the incoming values is specified with the first type field. After
5273 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5274 one pair for each predecessor basic block of the current block. Only values
5275 of <a href="#t_firstclass">first class</a> type may be used as the value
5276 arguments to the PHI node. Only labels may be used as the label
5277 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5278
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5279<p>There must be no non-phi instructions between the start of a basic block and
5280 the PHI instructions: i.e. PHI instructions must be first in a basic
5281 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5282
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5283<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5284 occur on the edge from the corresponding predecessor block to the current
5285 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5286 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5287
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5288<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5289<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5290 specified by the pair corresponding to the predecessor basic block that
5291 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5292
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5293<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5294<pre>
5295Loop: ; Infinite loop that counts from 0 on up...
5296 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5297 %nextindvar = add i32 %indvar, 1
5298 br label %Loop
5299</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5301</div>
5302
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5303<!-- _______________________________________________________________________ -->
5304<div class="doc_subsubsection">
5305 <a name="i_select">'<tt>select</tt>' Instruction</a>
5306</div>
5307
5308<div class="doc_text">
5309
5310<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5311<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5312 &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>
5313
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5314 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5315</pre>
5316
5317<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5318<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5319 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5320
5321
5322<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5323<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5324 values indicating the condition, and two values of the
5325 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5326 vectors and the condition is a scalar, then entire vectors are selected, not
5327 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5328
5329<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5330<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5331 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5332
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5333<p>If the condition is a vector of i1, then the value arguments must be vectors
5334 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5335
5336<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5337<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5338 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5339</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5340
5341<p>Note that the code generator does not yet support conditions
5342 with vector type.</p>
5343
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5344</div>
5345
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5346<!-- _______________________________________________________________________ -->
5347<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5348 <a name="i_call">'<tt>call</tt>' Instruction</a>
5349</div>
5350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5351<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5353<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5354<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5355 &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]5356</pre>
5357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5358<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5359<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5361<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5362<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5363
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5364<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5365 <li>The optional "tail" marker indicates that the callee function does not
5366 access any allocas or varargs in the caller. Note that calls may be
5367 marked "tail" even if they do not occur before
5368 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5369 present, the function call is eligible for tail call optimization,
5370 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5371 optimized into a jump</a>. The code generator may optimize calls marked
5372 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5373 sibling call optimization</a> when the caller and callee have
5374 matching signatures, or 2) forced tail call optimization when the
5375 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5376 <ul>
5377 <li>Caller and callee both have the calling
5378 convention <tt>fastcc</tt>.</li>
5379 <li>The call is in tail position (ret immediately follows call and ret
5380 uses value of call or is void).</li>
5381 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5382 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5383 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5384 constraints are met.</a></li>
5385 </ul>
5386 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5387
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5388 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5389 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5390 defaults to using C calling conventions. The calling convention of the
5391 call must match the calling convention of the target function, or else the
5392 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5395 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5396 '<tt>inreg</tt>' attributes are valid here.</li>
5397
5398 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5399 type of the return value. Functions that return no value are marked
5400 <tt><a href="#t_void">void</a></tt>.</li>
5401
5402 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5403 being invoked. The argument types must match the types implied by this
5404 signature. This type can be omitted if the function is not varargs and if
5405 the function type does not return a pointer to a function.</li>
5406
5407 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5408 be invoked. In most cases, this is a direct function invocation, but
5409 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5410 to function value.</li>
5411
5412 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5413 signature argument types and parameter attributes. All arguments must be
5414 of <a href="#t_firstclass">first class</a> type. If the function
5415 signature indicates the function accepts a variable number of arguments,
5416 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5417
5418 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5419 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5420 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5421</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5422
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5423<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5424<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5425 a specified function, with its incoming arguments bound to the specified
5426 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5427 function, control flow continues with the instruction after the function
5428 call, and the return value of the function is bound to the result
5429 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5430
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5431<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5432<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5433 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5434 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5435 %X = tail call i32 @foo() <i>; yields i32</i>
5436 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5437 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5438
5439 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5440 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5441 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5442 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5443 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5444 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5445</pre>
5446
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5447<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5448standard C99 library as being the C99 library functions, and may perform
5449optimizations or generate code for them under that assumption. This is
5450something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5451freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5453</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5454
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5455<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5456<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5457 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5458</div>
5459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5460<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5461
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5462<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5463<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5464 &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]5465</pre>
5466
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5467<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5468<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5469 the "variable argument" area of a function call. It is used to implement the
5470 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5471
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5472<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5474 argument. It returns a value of the specified argument type and increments
5475 the <tt>va_list</tt> to point to the next argument. The actual type
5476 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5477
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5478<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5480 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5481 to the next argument. For more information, see the variable argument
5482 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5483
5484<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]5485 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5486 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5487
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5488<p><tt>va_arg</tt> is an LLVM instruction instead of
5489 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5490 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5491
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5492<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5493<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5494
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5495<p>Note that the code generator does not yet fully support va_arg on many
5496 targets. Also, it does not currently support va_arg with aggregate types on
5497 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5499</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5500
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5501<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5502<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5503<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5504
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5505<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5506
5507<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508 well known names and semantics and are required to follow certain
5509 restrictions. Overall, these intrinsics represent an extension mechanism for
5510 the LLVM language that does not require changing all of the transformations
5511 in LLVM when adding to the language (or the bitcode reader/writer, the
5512 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5513
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5514<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5515 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5516 begin with this prefix. Intrinsic functions must always be external
5517 functions: you cannot define the body of intrinsic functions. Intrinsic
5518 functions may only be used in call or invoke instructions: it is illegal to
5519 take the address of an intrinsic function. Additionally, because intrinsic
5520 functions are part of the LLVM language, it is required if any are added that
5521 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5523<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5524 family of functions that perform the same operation but on different data
5525 types. Because LLVM can represent over 8 million different integer types,
5526 overloading is used commonly to allow an intrinsic function to operate on any
5527 integer type. One or more of the argument types or the result type can be
5528 overloaded to accept any integer type. Argument types may also be defined as
5529 exactly matching a previous argument's type or the result type. This allows
5530 an intrinsic function which accepts multiple arguments, but needs all of them
5531 to be of the same type, to only be overloaded with respect to a single
5532 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5533
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534<p>Overloaded intrinsics will have the names of its overloaded argument types
5535 encoded into its function name, each preceded by a period. Only those types
5536 which are overloaded result in a name suffix. Arguments whose type is matched
5537 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5538 can take an integer of any width and returns an integer of exactly the same
5539 integer width. This leads to a family of functions such as
5540 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5541 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5542 suffix is required. Because the argument's type is matched against the return
5543 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5544
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5545<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5546 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5547
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5548</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5549
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5550<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5551<div class="doc_subsection">
5552 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5553</div>
5554
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5555<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5556
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5557<p>Variable argument support is defined in LLVM with
5558 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5559 intrinsic functions. These functions are related to the similarly named
5560 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5561
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562<p>All of these functions operate on arguments that use a target-specific value
5563 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5564 not define what this type is, so all transformations should be prepared to
5565 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5566
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5567<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]5568 instruction and the variable argument handling intrinsic functions are
5569 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5570
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5571<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5572define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5573 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5574 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5575 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5576 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5577
5578 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5579 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5580
5581 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5582 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5583 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5584 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5585 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5586
5587 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5588 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5589 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5590}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5591
5592declare void @llvm.va_start(i8*)
5593declare void @llvm.va_copy(i8*, i8*)
5594declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5595</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5596
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5597</div>
5598
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5599<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5600<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5601 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5602</div>
5603
5604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5605<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5608<pre>
5609 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5610</pre>
5611
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5612<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5613<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5614 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]5615
5616<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5617<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]5618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5619<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5620<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]5621 macro available in C. In a target-dependent way, it initializes
5622 the <tt>va_list</tt> element to which the argument points, so that the next
5623 call to <tt>va_arg</tt> will produce the first variable argument passed to
5624 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5625 need to know the last argument of the function as the compiler can figure
5626 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5627
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5628</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5629
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5630<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5631<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5632 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5633</div>
5634
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5635<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5636
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5637<h5>Syntax:</h5>
5638<pre>
5639 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5640</pre>
5641
5642<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5643<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5644 which has been initialized previously
5645 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5646 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5647
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5648<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5649<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]5650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5651<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5652<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]5653 macro available in C. In a target-dependent way, it destroys
5654 the <tt>va_list</tt> element to which the argument points. Calls
5655 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5656 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5657 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5658
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5659</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5660
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5661<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5662<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5663 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5664</div>
5665
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5666<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5667
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5668<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5669<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5670 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5671</pre>
5672
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5673<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5674<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5675 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5677<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5678<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]5679 The second argument is a pointer to a <tt>va_list</tt> element to copy
5680 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5681
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5682<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5683<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]5684 macro available in C. In a target-dependent way, it copies the
5685 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5686 element. This intrinsic is necessary because
5687 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5688 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5690</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5691
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5692<!-- ======================================================================= -->
5693<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5694 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5695</div>
5696
5697<div class="doc_text">
5698
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5699<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5700Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5702roots on the stack</a>, as well as garbage collector implementations that
5703require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5704barriers. Front-ends for type-safe garbage collected languages should generate
5705these intrinsics to make use of the LLVM garbage collectors. For more details,
5706see <a href="GarbageCollection.html">Accurate Garbage Collection with
5707LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5708
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709<p>The garbage collection intrinsics only operate on objects in the generic
5710 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5711
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712</div>
5713
5714<!-- _______________________________________________________________________ -->
5715<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5716 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5717</div>
5718
5719<div class="doc_text">
5720
5721<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5722<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5723 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5724</pre>
5725
5726<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5727<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]5728 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5729
5730<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732 root pointer. The second pointer (which must be either a constant or a
5733 global value address) contains the meta-data to be associated with the
5734 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5735
5736<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5737<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]5738 location. At compile-time, the code generator generates information to allow
5739 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5740 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5741 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5742
5743</div>
5744
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5745<!-- _______________________________________________________________________ -->
5746<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5747 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5748</div>
5749
5750<div class="doc_text">
5751
5752<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5753<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5754 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755</pre>
5756
5757<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5758<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5759 locations, allowing garbage collector implementations that require read
5760 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5761
5762<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5763<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]5764 allocated from the garbage collector. The first object is a pointer to the
5765 start of the referenced object, if needed by the language runtime (otherwise
5766 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5767
5768<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5769<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770 instruction, but may be replaced with substantially more complex code by the
5771 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5772 may only be used in a function which <a href="#gc">specifies a GC
5773 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5774
5775</div>
5776
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5777<!-- _______________________________________________________________________ -->
5778<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5779 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5780</div>
5781
5782<div class="doc_text">
5783
5784<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5785<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5786 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5787</pre>
5788
5789<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5790<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791 locations, allowing garbage collector implementations that require write
5792 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5793
5794<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5795<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]5796 object to store it to, and the third is the address of the field of Obj to
5797 store to. If the runtime does not require a pointer to the object, Obj may
5798 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5799
5800<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5801<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5802 instruction, but may be replaced with substantially more complex code by the
5803 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5804 may only be used in a function which <a href="#gc">specifies a GC
5805 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5806
5807</div>
5808
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5809<!-- ======================================================================= -->
5810<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5811 <a name="int_codegen">Code Generator Intrinsics</a>
5812</div>
5813
5814<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815
5816<p>These intrinsics are provided by LLVM to expose special features that may
5817 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818
5819</div>
5820
5821<!-- _______________________________________________________________________ -->
5822<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5823 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
5826<div class="doc_text">
5827
5828<h5>Syntax:</h5>
5829<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5830 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5831</pre>
5832
5833<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5834<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5835 target-specific value indicating the return address of the current function
5836 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5837
5838<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5839<p>The argument to this intrinsic indicates which function to return the address
5840 for. Zero indicates the calling function, one indicates its caller, etc.
5841 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5842
5843<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5845 indicating the return address of the specified call frame, or zero if it
5846 cannot be identified. The value returned by this intrinsic is likely to be
5847 incorrect or 0 for arguments other than zero, so it should only be used for
5848 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5850<p>Note that calling this intrinsic does not prevent function inlining or other
5851 aggressive transformations, so the value returned may not be that of the
5852 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5853
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5854</div>
5855
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5856<!-- _______________________________________________________________________ -->
5857<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5858 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5859</div>
5860
5861<div class="doc_text">
5862
5863<h5>Syntax:</h5>
5864<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5865 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5866</pre>
5867
5868<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5870 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5871
5872<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873<p>The argument to this intrinsic indicates which function to return the frame
5874 pointer for. Zero indicates the calling function, one indicates its caller,
5875 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5876
5877<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5878<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5879 indicating the frame address of the specified call frame, or zero if it
5880 cannot be identified. The value returned by this intrinsic is likely to be
5881 incorrect or 0 for arguments other than zero, so it should only be used for
5882 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5883
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884<p>Note that calling this intrinsic does not prevent function inlining or other
5885 aggressive transformations, so the value returned may not be that of the
5886 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5887
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5888</div>
5889
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5892 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5893</div>
5894
5895<div class="doc_text">
5896
5897<h5>Syntax:</h5>
5898<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5899 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5900</pre>
5901
5902<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5904 of the function stack, for use
5905 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5906 useful for implementing language features like scoped automatic variable
5907 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5908
5909<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5910<p>This intrinsic returns a opaque pointer value that can be passed
5911 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5912 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5913 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5914 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5915 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5916 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5917
5918</div>
5919
5920<!-- _______________________________________________________________________ -->
5921<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5922 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5923</div>
5924
5925<div class="doc_text">
5926
5927<h5>Syntax:</h5>
5928<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5929 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5930</pre>
5931
5932<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5933<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5934 the function stack to the state it was in when the
5935 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5936 executed. This is useful for implementing language features like scoped
5937 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5938
5939<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5940<p>See the description
5941 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5942
5943</div>
5944
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5945<!-- _______________________________________________________________________ -->
5946<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5947 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5948</div>
5949
5950<div class="doc_text">
5951
5952<h5>Syntax:</h5>
5953<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5954 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]5955</pre>
5956
5957<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5959 insert a prefetch instruction if supported; otherwise, it is a noop.
5960 Prefetches have no effect on the behavior of the program but can change its
5961 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5962
5963<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5965 specifier determining if the fetch should be for a read (0) or write (1),
5966 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5967 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5968 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971<p>This intrinsic does not modify the behavior of the program. In particular,
5972 prefetches cannot trap and do not produce a value. On targets that support
5973 this intrinsic, the prefetch can provide hints to the processor cache for
5974 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5975
5976</div>
5977
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5978<!-- _______________________________________________________________________ -->
5979<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5980 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5981</div>
5982
5983<div class="doc_text">
5984
5985<h5>Syntax:</h5>
5986<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5987 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5988</pre>
5989
5990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5992 Counter (PC) in a region of code to simulators and other tools. The method
5993 is target specific, but it is expected that the marker will use exported
5994 symbols to transmit the PC of the marker. The marker makes no guarantees
5995 that it will remain with any specific instruction after optimizations. It is
5996 possible that the presence of a marker will inhibit optimizations. The
5997 intended use is to be inserted after optimizations to allow correlations of
5998 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5999
6000<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6005 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6006
6007</div>
6008
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6009<!-- _______________________________________________________________________ -->
6010<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6011 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6012</div>
6013
6014<div class="doc_text">
6015
6016<h5>Syntax:</h5>
6017<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6018 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6019</pre>
6020
6021<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6022<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6023 counter register (or similar low latency, high accuracy clocks) on those
6024 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6025 should map to RPCC. As the backing counters overflow quickly (on the order
6026 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6027
6028<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029<p>When directly supported, reading the cycle counter should not modify any
6030 memory. Implementations are allowed to either return a application specific
6031 value or a system wide value. On backends without support, this is lowered
6032 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6033
6034</div>
6035
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6036<!-- ======================================================================= -->
6037<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6038 <a name="int_libc">Standard C Library Intrinsics</a>
6039</div>
6040
6041<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6042
6043<p>LLVM provides intrinsics for a few important standard C library functions.
6044 These intrinsics allow source-language front-ends to pass information about
6045 the alignment of the pointer arguments to the code generator, providing
6046 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6047
6048</div>
6049
6050<!-- _______________________________________________________________________ -->
6051<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6052 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6053</div>
6054
6055<div class="doc_text">
6056
6057<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058<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]6059 integer bit width and for different address spaces. Not all targets support
6060 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6061
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6062<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6063 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]6064 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6065 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]6066 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6071 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6073<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6074 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6075 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6076
6077<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6078
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6079<p>The first argument is a pointer to the destination, the second is a pointer
6080 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6081 number of bytes to copy, the fourth argument is the alignment of the
6082 source and destination locations, and the fifth is a boolean indicating a
6083 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6084
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6085<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]6086 then the caller guarantees that both the source and destination pointers are
6087 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6088
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6089<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6090 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6091 The detailed access behavior is not very cleanly specified and it is unwise
6092 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6093
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6094<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6096<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6097 source location to the destination location, which are not allowed to
6098 overlap. It copies "len" bytes of memory over. If the argument is known to
6099 be aligned to some boundary, this can be specified as the fourth argument,
6100 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6101
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6102</div>
6103
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6104<!-- _______________________________________________________________________ -->
6105<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6106 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6107</div>
6108
6109<div class="doc_text">
6110
6111<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6112<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]6113 width and for different address space. Not all targets support all bit
6114 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6115
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6116<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6117 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]6118 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6119 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]6120 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6121</pre>
6122
6123<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6124<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6125 source location to the destination location. It is similar to the
6126 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6127 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6129<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6130 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6131 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6132
6133<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6135<p>The first argument is a pointer to the destination, the second is a pointer
6136 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6137 number of bytes to copy, the fourth argument is the alignment of the
6138 source and destination locations, and the fifth is a boolean indicating a
6139 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6140
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6141<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]6142 then the caller guarantees that the source and destination pointers are
6143 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6144
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6145<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6146 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6147 The detailed access behavior is not very cleanly specified and it is unwise
6148 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6149
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6150<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6153 source location to the destination location, which may overlap. It copies
6154 "len" bytes of memory over. If the argument is known to be aligned to some
6155 boundary, this can be specified as the fourth argument, otherwise it should
6156 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6157
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6158</div>
6159
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6160<!-- _______________________________________________________________________ -->
6161<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6162 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6163</div>
6164
6165<div class="doc_text">
6166
6167<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6168<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]6169 width and for different address spaces. However, not all targets support all
6170 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6171
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6172<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6173 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6174 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6175 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6176 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6177</pre>
6178
6179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6180<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6181 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6182
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6183<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6184 intrinsic does not return a value and takes extra alignment/volatile
6185 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6186
6187<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6188<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]6189 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6190 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6191 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6192
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6193<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]6194 then the caller guarantees that the destination pointer is aligned to that
6195 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6196
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6197<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6198 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6199 The detailed access behavior is not very cleanly specified and it is unwise
6200 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6201
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6202<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6204 at the destination location. If the argument is known to be aligned to some
6205 boundary, this can be specified as the fourth argument, otherwise it should
6206 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6207
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6208</div>
6209
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6210<!-- _______________________________________________________________________ -->
6211<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6212 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6213</div>
6214
6215<div class="doc_text">
6216
6217<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6218<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6219 floating point or vector of floating point type. Not all targets support all
6220 types however.</p>
6221
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6222<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6223 declare float @llvm.sqrt.f32(float %Val)
6224 declare double @llvm.sqrt.f64(double %Val)
6225 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6226 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6227 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6228</pre>
6229
6230<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6231<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6232 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6233 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6234 behavior for negative numbers other than -0.0 (which allows for better
6235 optimization, because there is no need to worry about errno being
6236 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]6237
6238<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The argument and return value are floating point numbers of the same
6240 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the sqrt of the specified operand if it is a
6244 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6245
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6246</div>
6247
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6250 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6257 floating point or vector of floating point type. Not all targets support all
6258 types however.</p>
6259
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6260<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6261 declare float @llvm.powi.f32(float %Val, i32 %power)
6262 declare double @llvm.powi.f64(double %Val, i32 %power)
6263 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6264 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6265 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6269<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6270 specified (positive or negative) power. The order of evaluation of
6271 multiplications is not defined. When a vector of floating point type is
6272 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6273
6274<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6275<p>The second argument is an integer power, and the first is a value to raise to
6276 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6277
6278<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6279<p>This function returns the first value raised to the second power with an
6280 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6281
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6282</div>
6283
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6284<!-- _______________________________________________________________________ -->
6285<div class="doc_subsubsection">
6286 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6287</div>
6288
6289<div class="doc_text">
6290
6291<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6292<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6293 floating point or vector of floating point type. Not all targets support all
6294 types however.</p>
6295
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6296<pre>
6297 declare float @llvm.sin.f32(float %Val)
6298 declare double @llvm.sin.f64(double %Val)
6299 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6300 declare fp128 @llvm.sin.f128(fp128 %Val)
6301 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6302</pre>
6303
6304<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6305<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6308<p>The argument and return value are floating point numbers of the same
6309 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>This function returns the sine of the specified operand, returning the same
6313 values as the libm <tt>sin</tt> functions would, and handles error conditions
6314 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6315
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6316</div>
6317
6318<!-- _______________________________________________________________________ -->
6319<div class="doc_subsubsection">
6320 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6321</div>
6322
6323<div class="doc_text">
6324
6325<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6326<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6327 floating point or vector of floating point type. Not all targets support all
6328 types however.</p>
6329
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6330<pre>
6331 declare float @llvm.cos.f32(float %Val)
6332 declare double @llvm.cos.f64(double %Val)
6333 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6334 declare fp128 @llvm.cos.f128(fp128 %Val)
6335 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6336</pre>
6337
6338<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6339<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6340
6341<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6342<p>The argument and return value are floating point numbers of the same
6343 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6344
6345<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6346<p>This function returns the cosine of the specified operand, returning the same
6347 values as the libm <tt>cos</tt> functions would, and handles error conditions
6348 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6349
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6350</div>
6351
6352<!-- _______________________________________________________________________ -->
6353<div class="doc_subsubsection">
6354 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6355</div>
6356
6357<div class="doc_text">
6358
6359<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6360<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6361 floating point or vector of floating point type. Not all targets support all
6362 types however.</p>
6363
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6364<pre>
6365 declare float @llvm.pow.f32(float %Val, float %Power)
6366 declare double @llvm.pow.f64(double %Val, double %Power)
6367 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6368 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6369 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6370</pre>
6371
6372<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6373<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6374 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6375
6376<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6377<p>The second argument is a floating point power, and the first is a value to
6378 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6379
6380<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6381<p>This function returns the first value raised to the second power, returning
6382 the same values as the libm <tt>pow</tt> functions would, and handles error
6383 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6384
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6385</div>
6386
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6387<!-- ======================================================================= -->
6388<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6389 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6390</div>
6391
6392<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6393
6394<p>LLVM provides intrinsics for a few important bit manipulation operations.
6395 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6396
6397</div>
6398
6399<!-- _______________________________________________________________________ -->
6400<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6401 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6402</div>
6403
6404<div class="doc_text">
6405
6406<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6407<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6409
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6410<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6411 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6412 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6413 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6414</pre>
6415
6416<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6417<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6418 values with an even number of bytes (positive multiple of 16 bits). These
6419 are useful for performing operations on data that is not in the target's
6420 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6421
6422<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6423<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6424 and low byte of the input i16 swapped. Similarly,
6425 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6426 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6427 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6428 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6429 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6430 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6431
6432</div>
6433
6434<!-- _______________________________________________________________________ -->
6435<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6436 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6437</div>
6438
6439<div class="doc_text">
6440
6441<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6442<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]6443 width. Not all targets support all bit widths however.</p>
6444
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6445<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6446 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6447 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6448 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6449 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6450 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6455 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6456
6457<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458<p>The only argument is the value to be counted. The argument may be of any
6459 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6460
6461<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<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]6463
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6464</div>
6465
6466<!-- _______________________________________________________________________ -->
6467<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6468 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6469</div>
6470
6471<div class="doc_text">
6472
6473<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6474<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6475 integer bit width. Not all targets support all bit widths however.</p>
6476
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6477<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6478 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6479 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6480 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6481 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6482 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6483</pre>
6484
6485<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6486<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6487 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6488
6489<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490<p>The only argument is the value to be counted. The argument may be of any
6491 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6492
6493<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6495 zeros in a variable. If the src == 0 then the result is the size in bits of
6496 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6497
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6498</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6499
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6500<!-- _______________________________________________________________________ -->
6501<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6502 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6503</div>
6504
6505<div class="doc_text">
6506
6507<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6508<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6509 integer bit width. Not all targets support all bit widths however.</p>
6510
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6511<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6512 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6513 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6514 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6515 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6516 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6517</pre>
6518
6519<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6520<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6521 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6522
6523<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6524<p>The only argument is the value to be counted. The argument may be of any
6525 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6526
6527<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6528<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6529 zeros in a variable. If the src == 0 then the result is the size in bits of
6530 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6531
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6532</div>
6533
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6534<!-- ======================================================================= -->
6535<div class="doc_subsection">
6536 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6537</div>
6538
6539<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540
6541<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6542
6543</div>
6544
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6545<!-- _______________________________________________________________________ -->
6546<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6547 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6548</div>
6549
6550<div class="doc_text">
6551
6552<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553<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]6554 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6555
6556<pre>
6557 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6558 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6559 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6560</pre>
6561
6562<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6563<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6564 a signed addition of the two arguments, and indicate whether an overflow
6565 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6566
6567<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6568<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]6569 be of integer types of any bit width, but they must have the same bit
6570 width. The second element of the result structure must be of
6571 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6572 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573
6574<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6575<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576 a signed addition of the two variables. They return a structure &mdash; the
6577 first element of which is the signed summation, and the second element of
6578 which is a bit specifying if the signed summation resulted in an
6579 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6580
6581<h5>Examples:</h5>
6582<pre>
6583 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6584 %sum = extractvalue {i32, i1} %res, 0
6585 %obit = extractvalue {i32, i1} %res, 1
6586 br i1 %obit, label %overflow, label %normal
6587</pre>
6588
6589</div>
6590
6591<!-- _______________________________________________________________________ -->
6592<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6593 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6594</div>
6595
6596<div class="doc_text">
6597
6598<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6599<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]6600 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6601
6602<pre>
6603 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6604 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6605 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6606</pre>
6607
6608<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6609<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6610 an unsigned addition of the two arguments, and indicate whether a carry
6611 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6612
6613<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6614<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]6615 be of integer types of any bit width, but they must have the same bit
6616 width. The second element of the result structure must be of
6617 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6618 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6619
6620<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6622 an unsigned addition of the two arguments. They return a structure &mdash;
6623 the first element of which is the sum, and the second element of which is a
6624 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6625
6626<h5>Examples:</h5>
6627<pre>
6628 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6629 %sum = extractvalue {i32, i1} %res, 0
6630 %obit = extractvalue {i32, i1} %res, 1
6631 br i1 %obit, label %carry, label %normal
6632</pre>
6633
6634</div>
6635
6636<!-- _______________________________________________________________________ -->
6637<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6638 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6639</div>
6640
6641<div class="doc_text">
6642
6643<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6644<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]6645 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6646
6647<pre>
6648 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6649 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6650 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6651</pre>
6652
6653<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6654<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6655 a signed subtraction of the two arguments, and indicate whether an overflow
6656 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6657
6658<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659<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]6660 be of integer types of any bit width, but they must have the same bit
6661 width. The second element of the result structure must be of
6662 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6663 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664
6665<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6667 a signed subtraction of the two arguments. They return a structure &mdash;
6668 the first element of which is the subtraction, and the second element of
6669 which is a bit specifying if the signed subtraction resulted in an
6670 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671
6672<h5>Examples:</h5>
6673<pre>
6674 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6675 %sum = extractvalue {i32, i1} %res, 0
6676 %obit = extractvalue {i32, i1} %res, 1
6677 br i1 %obit, label %overflow, label %normal
6678</pre>
6679
6680</div>
6681
6682<!-- _______________________________________________________________________ -->
6683<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6684 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6685</div>
6686
6687<div class="doc_text">
6688
6689<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690<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]6691 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<pre>
6694 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6695 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6696 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6697</pre>
6698
6699<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6700<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6701 an unsigned subtraction of the two arguments, and indicate whether an
6702 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6703
6704<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6705<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]6706 be of integer types of any bit width, but they must have the same bit
6707 width. The second element of the result structure must be of
6708 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6709 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6710
6711<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6712<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6713 an unsigned subtraction of the two arguments. They return a structure &mdash;
6714 the first element of which is the subtraction, and the second element of
6715 which is a bit specifying if the unsigned subtraction resulted in an
6716 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6717
6718<h5>Examples:</h5>
6719<pre>
6720 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6721 %sum = extractvalue {i32, i1} %res, 0
6722 %obit = extractvalue {i32, i1} %res, 1
6723 br i1 %obit, label %overflow, label %normal
6724</pre>
6725
6726</div>
6727
6728<!-- _______________________________________________________________________ -->
6729<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6730 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6731</div>
6732
6733<div class="doc_text">
6734
6735<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6736<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]6737 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6738
6739<pre>
6740 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6741 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6742 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6743</pre>
6744
6745<h5>Overview:</h5>
6746
6747<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748 a signed multiplication of the two arguments, and indicate whether an
6749 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6750
6751<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6752<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]6753 be of integer types of any bit width, but they must have the same bit
6754 width. The second element of the result structure must be of
6755 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6756 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6757
6758<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6759<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6760 a signed multiplication of the two arguments. They return a structure &mdash;
6761 the first element of which is the multiplication, and the second element of
6762 which is a bit specifying if the signed multiplication resulted in an
6763 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6764
6765<h5>Examples:</h5>
6766<pre>
6767 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6768 %sum = extractvalue {i32, i1} %res, 0
6769 %obit = extractvalue {i32, i1} %res, 1
6770 br i1 %obit, label %overflow, label %normal
6771</pre>
6772
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6773</div>
6774
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6775<!-- _______________________________________________________________________ -->
6776<div class="doc_subsubsection">
6777 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6778</div>
6779
6780<div class="doc_text">
6781
6782<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6783<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]6784 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6785
6786<pre>
6787 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6788 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6789 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6790</pre>
6791
6792<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6793<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794 a unsigned multiplication of the two arguments, and indicate whether an
6795 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6796
6797<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6798<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]6799 be of integer types of any bit width, but they must have the same bit
6800 width. The second element of the result structure must be of
6801 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6802 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6803
6804<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6805<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6806 an unsigned multiplication of the two arguments. They return a structure
6807 &mdash; the first element of which is the multiplication, and the second
6808 element of which is a bit specifying if the unsigned multiplication resulted
6809 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6814 %sum = extractvalue {i32, i1} %res, 0
6815 %obit = extractvalue {i32, i1} %res, 1
6816 br i1 %obit, label %overflow, label %normal
6817</pre>
6818
6819</div>
6820
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6821<!-- ======================================================================= -->
6822<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6823 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6824</div>
6825
6826<div class="doc_text">
6827
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6828<p>Half precision floating point is a storage-only format. This means that it is
6829 a dense encoding (in memory) but does not support computation in the
6830 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6831
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6832<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6833 value as an i16, then convert it to float with <a
6834 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6835 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6836 double etc). To store the value back to memory, it is first converted to
6837 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6838 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6839 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6840</div>
6841
6842<!-- _______________________________________________________________________ -->
6843<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6844 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6845</div>
6846
6847<div class="doc_text">
6848
6849<h5>Syntax:</h5>
6850<pre>
6851 declare i16 @llvm.convert.to.fp16(f32 %a)
6852</pre>
6853
6854<h5>Overview:</h5>
6855<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6856 a conversion from single precision floating point format to half precision
6857 floating point format.</p>
6858
6859<h5>Arguments:</h5>
6860<p>The intrinsic function contains single argument - the value to be
6861 converted.</p>
6862
6863<h5>Semantics:</h5>
6864<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6865 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6866 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6867 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6868
6869<h5>Examples:</h5>
6870<pre>
6871 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6872 store i16 %res, i16* @x, align 2
6873</pre>
6874
6875</div>
6876
6877<!-- _______________________________________________________________________ -->
6878<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6879 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6880</div>
6881
6882<div class="doc_text">
6883
6884<h5>Syntax:</h5>
6885<pre>
6886 declare f32 @llvm.convert.from.fp16(i16 %a)
6887</pre>
6888
6889<h5>Overview:</h5>
6890<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6891 a conversion from half precision floating point format to single precision
6892 floating point format.</p>
6893
6894<h5>Arguments:</h5>
6895<p>The intrinsic function contains single argument - the value to be
6896 converted.</p>
6897
6898<h5>Semantics:</h5>
6899<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6900 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6901 precision floating point format. The input half-float value is represented by
6902 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6903
6904<h5>Examples:</h5>
6905<pre>
6906 %a = load i16* @x, align 2
6907 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6908</pre>
6909
6910</div>
6911
6912<!-- ======================================================================= -->
6913<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6914 <a name="int_debugger">Debugger Intrinsics</a>
6915</div>
6916
6917<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6919<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6920 prefix), are described in
6921 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6922 Level Debugging</a> document.</p>
6923
6924</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6925
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6926<!-- ======================================================================= -->
6927<div class="doc_subsection">
6928 <a name="int_eh">Exception Handling Intrinsics</a>
6929</div>
6930
6931<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6932
6933<p>The LLVM exception handling intrinsics (which all start with
6934 <tt>llvm.eh.</tt> prefix), are described in
6935 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6936 Handling</a> document.</p>
6937
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6938</div>
6939
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6940<!-- ======================================================================= -->
6941<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6942 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6943</div>
6944
6945<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946
6947<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6948 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6949 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950 function pointer lacking the nest parameter - the caller does not need to
6951 provide a value for it. Instead, the value to use is stored in advance in a
6952 "trampoline", a block of memory usually allocated on the stack, which also
6953 contains code to splice the nest value into the argument list. This is used
6954 to implement the GCC nested function address extension.</p>
6955
6956<p>For example, if the function is
6957 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6958 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6959 follows:</p>
6960
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6961<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6962 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6963 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6964 %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]6965 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6966</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6967
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6968<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6969 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6971</div>
6972
6973<!-- _______________________________________________________________________ -->
6974<div class="doc_subsubsection">
6975 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6976</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6977
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6978<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6980<h5>Syntax:</h5>
6981<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6982 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]6983</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6987 function pointer suitable for executing it.</p>
6988
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6991 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6992 sufficiently aligned block of memory; this memory is written to by the
6993 intrinsic. Note that the size and the alignment are target-specific - LLVM
6994 currently provides no portable way of determining them, so a front-end that
6995 generates this intrinsic needs to have some target-specific knowledge.
6996 The <tt>func</tt> argument must hold a function bitcast to
6997 an <tt>i8*</tt>.</p>
6998
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7001 dependent code, turning it into a function. A pointer to this function is
7002 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7003 function pointer type</a> before being called. The new function's signature
7004 is the same as that of <tt>func</tt> with any arguments marked with
7005 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7006 is allowed, and it must be of pointer type. Calling the new function is
7007 equivalent to calling <tt>func</tt> with the same argument list, but
7008 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7009 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7010 by <tt>tramp</tt> is modified, then the effect of any later call to the
7011 returned function pointer is undefined.</p>
7012
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7013</div>
7014
7015<!-- ======================================================================= -->
7016<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7017 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7018</div>
7019
7020<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7022<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7023 hardware constructs for atomic operations and memory synchronization. This
7024 provides an interface to the hardware, not an interface to the programmer. It
7025 is aimed at a low enough level to allow any programming models or APIs
7026 (Application Programming Interfaces) which need atomic behaviors to map
7027 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7028 hardware provides a "universal IR" for source languages, it also provides a
7029 starting point for developing a "universal" atomic operation and
7030 synchronization IR.</p>
7031
7032<p>These do <em>not</em> form an API such as high-level threading libraries,
7033 software transaction memory systems, atomic primitives, and intrinsic
7034 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7035 application libraries. The hardware interface provided by LLVM should allow
7036 a clean implementation of all of these APIs and parallel programming models.
7037 No one model or paradigm should be selected above others unless the hardware
7038 itself ubiquitously does so.</p>
7039
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7040</div>
7041
7042<!-- _______________________________________________________________________ -->
7043<div class="doc_subsubsection">
7044 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7045</div>
7046<div class="doc_text">
7047<h5>Syntax:</h5>
7048<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7049 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]7050</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7052<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7053<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7054 specific pairs of memory access types.</p>
7055
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7056<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7057<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7058 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7059 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7060 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7061
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062<ul>
7063 <li><tt>ll</tt>: load-load barrier</li>
7064 <li><tt>ls</tt>: load-store barrier</li>
7065 <li><tt>sl</tt>: store-load barrier</li>
7066 <li><tt>ss</tt>: store-store barrier</li>
7067 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7068</ul>
7069
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7070<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071<p>This intrinsic causes the system to enforce some ordering constraints upon
7072 the loads and stores of the program. This barrier does not
7073 indicate <em>when</em> any events will occur, it only enforces
7074 an <em>order</em> in which they occur. For any of the specified pairs of load
7075 and store operations (f.ex. load-load, or store-load), all of the first
7076 operations preceding the barrier will complete before any of the second
7077 operations succeeding the barrier begin. Specifically the semantics for each
7078 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7079
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<ul>
7081 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7082 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7083 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7084 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7085 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7086 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7087 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7088 load after the barrier begins.</li>
7089</ul>
7090
7091<p>These semantics are applied with a logical "and" behavior when more than one
7092 is enabled in a single memory barrier intrinsic.</p>
7093
7094<p>Backends may implement stronger barriers than those requested when they do
7095 not support as fine grained a barrier as requested. Some architectures do
7096 not need all types of barriers and on such architectures, these become
7097 noops.</p>
7098
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7099<h5>Example:</h5>
7100<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7101%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7102%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7103 store i32 4, %ptr
7104
7105%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7106 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7107 <i>; guarantee the above finishes</i>
7108 store i32 8, %ptr <i>; before this begins</i>
7109</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7110
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7111</div>
7112
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7113<!-- _______________________________________________________________________ -->
7114<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7115 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7116</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7117
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7118<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7120<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7121<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7122 any integer bit width and for different address spaces. Not all targets
7123 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7124
7125<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7126 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7127 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7128 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7129 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]7130</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7131
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7132<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7133<p>This loads a value in memory and compares it to a given value. If they are
7134 equal, it stores a new value into the memory.</p>
7135
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7137<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7138 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7139 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7140 this integer type. While any bit width integer may be used, targets may only
7141 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7142
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7143<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7144<p>This entire intrinsic must be executed atomically. It first loads the value
7145 in memory pointed to by <tt>ptr</tt> and compares it with the
7146 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7147 memory. The loaded value is yielded in all cases. This provides the
7148 equivalent of an atomic compare-and-swap operation within the SSA
7149 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7151<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7152<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7153%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7154%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7155 store i32 4, %ptr
7156
7157%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7158%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159 <i>; yields {i32}:result1 = 4</i>
7160%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7161%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7162
7163%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7164%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165 <i>; yields {i32}:result2 = 8</i>
7166%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7167
7168%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7169</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7171</div>
7172
7173<!-- _______________________________________________________________________ -->
7174<div class="doc_subsubsection">
7175 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7176</div>
7177<div class="doc_text">
7178<h5>Syntax:</h5>
7179
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7180<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7181 integer bit width. Not all targets support all bit widths however.</p>
7182
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7183<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7184 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7185 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7186 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7187 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]7188</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7189
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7190<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7191<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7192 the value from memory. It then stores the value in <tt>val</tt> in the memory
7193 at <tt>ptr</tt>.</p>
7194
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7195<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7196<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7197 the <tt>val</tt> argument and the result must be integers of the same bit
7198 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7199 integer type. The targets may only lower integer representations they
7200 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7202<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7204 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7205 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7207<h5>Examples:</h5>
7208<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7209%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7210%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211 store i32 4, %ptr
7212
7213%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7214%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7215 <i>; yields {i32}:result1 = 4</i>
7216%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7217%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7218
7219%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7220%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7221 <i>; yields {i32}:result2 = 8</i>
7222
7223%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7224%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7225</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7226
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7227</div>
7228
7229<!-- _______________________________________________________________________ -->
7230<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7231 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7232
7233</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7234
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7235<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7236
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7237<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7238<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7239 any integer bit width. Not all targets support all bit widths however.</p>
7240
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7241<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7242 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7243 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7244 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7245 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]7246</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7247
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248<h5>Overview:</h5>
7249<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7250 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7251
7252<h5>Arguments:</h5>
7253<p>The intrinsic takes two arguments, the first a pointer to an integer value
7254 and the second an integer value. The result is also an integer value. These
7255 integer types can have any bit width, but they must all have the same bit
7256 width. The targets may only lower integer representations they support.</p>
7257
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7258<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7259<p>This intrinsic does a series of operations atomically. It first loads the
7260 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7261 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]7262
7263<h5>Examples:</h5>
7264<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7265%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7266%ptr = bitcast i8* %mallocP to i32*
7267 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7268%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7269 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7270%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7271 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7272%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7273 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7274%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7275</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7277</div>
7278
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7279<!-- _______________________________________________________________________ -->
7280<div class="doc_subsubsection">
7281 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7282
7283</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7284
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7285<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7286
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7287<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7288<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7289 any integer bit width and for different address spaces. Not all targets
7290 support all bit widths however.</p>
7291
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7292<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7293 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7294 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7295 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7296 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]7297</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7298
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7300<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7301 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7302
7303<h5>Arguments:</h5>
7304<p>The intrinsic takes two arguments, the first a pointer to an integer value
7305 and the second an integer value. The result is also an integer value. These
7306 integer types can have any bit width, but they must all have the same bit
7307 width. The targets may only lower integer representations they support.</p>
7308
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7309<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7310<p>This intrinsic does a series of operations atomically. It first loads the
7311 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7312 result to <tt>ptr</tt>. It yields the original value stored
7313 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7314
7315<h5>Examples:</h5>
7316<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7317%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7318%ptr = bitcast i8* %mallocP to i32*
7319 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7320%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7321 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7322%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7323 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7324%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7325 <i>; yields {i32}:result3 = 2</i>
7326%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7327</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7328
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7329</div>
7330
7331<!-- _______________________________________________________________________ -->
7332<div class="doc_subsubsection">
7333 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7334 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7335 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7336 <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]7337</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7338
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7339<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7340
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7342<p>These are overloaded intrinsics. You can
7343 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7344 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7345 bit width and for different address spaces. Not all targets support all bit
7346 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7347
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7349 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7350 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7351 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7352 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]7353</pre>
7354
7355<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7356 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7357 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7358 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7359 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]7360</pre>
7361
7362<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7363 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7364 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7365 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7366 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]7367</pre>
7368
7369<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7370 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7371 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7372 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7373 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]7374</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7375
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7376<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7377<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7378 the value stored in memory at <tt>ptr</tt>. It yields the original value
7379 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7381<h5>Arguments:</h5>
7382<p>These intrinsics take two arguments, the first a pointer to an integer value
7383 and the second an integer value. The result is also an integer value. These
7384 integer types can have any bit width, but they must all have the same bit
7385 width. The targets may only lower integer representations they support.</p>
7386
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7387<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388<p>These intrinsics does a series of operations atomically. They first load the
7389 value stored at <tt>ptr</tt>. They then do the bitwise
7390 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7391 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7392
7393<h5>Examples:</h5>
7394<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7395%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7396%ptr = bitcast i8* %mallocP to i32*
7397 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7398%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7399 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7400%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7401 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7402%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7403 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7404%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7405 <i>; yields {i32}:result3 = FF</i>
7406%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7407</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7409</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410
7411<!-- _______________________________________________________________________ -->
7412<div class="doc_subsubsection">
7413 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7414 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7415 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7416 <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]7417</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7420
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7421<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7422<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7423 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7424 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7425 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7426
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7427<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7428 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7429 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7430 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7431 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]7432</pre>
7433
7434<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7435 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7436 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7437 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7438 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]7439</pre>
7440
7441<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7442 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7443 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7444 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7445 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]7446</pre>
7447
7448<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7449 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7450 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7451 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7452 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]7453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7454
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7455<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7456<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7457 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7458 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7459
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7460<h5>Arguments:</h5>
7461<p>These intrinsics take two arguments, the first a pointer to an integer value
7462 and the second an integer value. The result is also an integer value. These
7463 integer types can have any bit width, but they must all have the same bit
7464 width. The targets may only lower integer representations they support.</p>
7465
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7466<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7467<p>These intrinsics does a series of operations atomically. They first load the
7468 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7469 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7470 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7471
7472<h5>Examples:</h5>
7473<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7474%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7475%ptr = bitcast i8* %mallocP to i32*
7476 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7477%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7478 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7479%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7480 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7481%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7482 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7483%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7484 <i>; yields {i32}:result3 = 8</i>
7485%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7486</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7487
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7488</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7489
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7490
7491<!-- ======================================================================= -->
7492<div class="doc_subsection">
7493 <a name="int_memorymarkers">Memory Use Markers</a>
7494</div>
7495
7496<div class="doc_text">
7497
7498<p>This class of intrinsics exists to information about the lifetime of memory
7499 objects and ranges where variables are immutable.</p>
7500
7501</div>
7502
7503<!-- _______________________________________________________________________ -->
7504<div class="doc_subsubsection">
7505 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7506</div>
7507
7508<div class="doc_text">
7509
7510<h5>Syntax:</h5>
7511<pre>
7512 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7513</pre>
7514
7515<h5>Overview:</h5>
7516<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7517 object's lifetime.</p>
7518
7519<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7520<p>The first argument is a constant integer representing the size of the
7521 object, or -1 if it is variable sized. The second argument is a pointer to
7522 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7523
7524<h5>Semantics:</h5>
7525<p>This intrinsic indicates that before this point in the code, the value of the
7526 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]7527 never be used and has an undefined value. A load from the pointer that
7528 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7529 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7547 object's lifetime.</p>
7548
7549<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7550<p>The first argument is a constant integer representing the size of the
7551 object, or -1 if it is variable sized. The second argument is a pointer to
7552 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7553
7554<h5>Semantics:</h5>
7555<p>This intrinsic indicates that after this point in the code, the value of the
7556 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7557 never be used and has an undefined value. Any stores into the memory object
7558 following this intrinsic may be removed as dead.
7559
7560</div>
7561
7562<!-- _______________________________________________________________________ -->
7563<div class="doc_subsubsection">
7564 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7565</div>
7566
7567<div class="doc_text">
7568
7569<h5>Syntax:</h5>
7570<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7571 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7572</pre>
7573
7574<h5>Overview:</h5>
7575<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7576 a memory object will not change.</p>
7577
7578<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7579<p>The first argument is a constant integer representing the size of the
7580 object, or -1 if it is variable sized. The second argument is a pointer to
7581 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7582
7583<h5>Semantics:</h5>
7584<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7585 the return value, the referenced memory location is constant and
7586 unchanging.</p>
7587
7588</div>
7589
7590<!-- _______________________________________________________________________ -->
7591<div class="doc_subsubsection">
7592 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7593</div>
7594
7595<div class="doc_text">
7596
7597<h5>Syntax:</h5>
7598<pre>
7599 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7600</pre>
7601
7602<h5>Overview:</h5>
7603<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7604 a memory object are mutable.</p>
7605
7606<h5>Arguments:</h5>
7607<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7608 The second argument is a constant integer representing the size of the
7609 object, or -1 if it is variable sized and the third argument is a pointer
7610 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7611
7612<h5>Semantics:</h5>
7613<p>This intrinsic indicates that the memory is mutable again.</p>
7614
7615</div>
7616
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7617<!-- ======================================================================= -->
7618<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7619 <a name="int_general">General Intrinsics</a>
7620</div>
7621
7622<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7623
7624<p>This class of intrinsics is designed to be generic and has no specific
7625 purpose.</p>
7626
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7627</div>
7628
7629<!-- _______________________________________________________________________ -->
7630<div class="doc_subsubsection">
7631 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7632</div>
7633
7634<div class="doc_text">
7635
7636<h5>Syntax:</h5>
7637<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7638 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]7639</pre>
7640
7641<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7642<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7643
7644<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7645<p>The first argument is a pointer to a value, the second is a pointer to a
7646 global string, the third is a pointer to a global string which is the source
7647 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7650<p>This intrinsic allows annotation of local variables with arbitrary strings.
7651 This can be useful for special purpose optimizations that want to look for
7652 these annotations. These have no other defined use, they are ignored by code
7653 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7654
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7655</div>
7656
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7657<!-- _______________________________________________________________________ -->
7658<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7659 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7660</div>
7661
7662<div class="doc_text">
7663
7664<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7666 any integer bit width.</p>
7667
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7668<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7669 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7670 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7671 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7672 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7673 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]7674</pre>
7675
7676<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7677<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7678
7679<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7680<p>The first argument is an integer value (result of some expression), the
7681 second is a pointer to a global string, the third is a pointer to a global
7682 string which is the source file name, and the last argument is the line
7683 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7684
7685<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7686<p>This intrinsic allows annotations to be put on arbitrary expressions with
7687 arbitrary strings. This can be useful for special purpose optimizations that
7688 want to look for these annotations. These have no other defined use, they
7689 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7690
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7691</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7692
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7693<!-- _______________________________________________________________________ -->
7694<div class="doc_subsubsection">
7695 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7696</div>
7697
7698<div class="doc_text">
7699
7700<h5>Syntax:</h5>
7701<pre>
7702 declare void @llvm.trap()
7703</pre>
7704
7705<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7707
7708<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7709<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7710
7711<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7712<p>This intrinsics is lowered to the target dependent trap instruction. If the
7713 target does not have a trap instruction, this intrinsic will be lowered to
7714 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7715
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7716</div>
7717
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7718<!-- _______________________________________________________________________ -->
7719<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7720 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7721</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7722
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7723<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7724
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7725<h5>Syntax:</h5>
7726<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7727 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7728</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7729
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7730<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7731<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7732 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7733 ensure that it is placed on the stack before local variables.</p>
7734
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7735<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7736<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7737 arguments. The first argument is the value loaded from the stack
7738 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7739 that has enough space to hold the value of the guard.</p>
7740
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7741<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7742<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7743 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7744 stack. This is to ensure that if a local variable on the stack is
7745 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7746 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7747 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7748 function.</p>
7749
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7750</div>
7751
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7752<!-- _______________________________________________________________________ -->
7753<div class="doc_subsubsection">
7754 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7755</div>
7756
7757<div class="doc_text">
7758
7759<h5>Syntax:</h5>
7760<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7761 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7762 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7763</pre>
7764
7765<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7766<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7767 the optimizers to determine at compile time whether a) an operation (like
7768 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7769 runtime check for overflow isn't necessary. An object in this context means
7770 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7771
7772<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7773<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7774 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7775 is a boolean 0 or 1. This argument determines whether you want the
7776 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]7777 1, variables are not allowed.</p>
7778
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7779<h5>Semantics:</h5>
7780<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7781 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7782 depending on the <tt>type</tt> argument, if the size cannot be determined at
7783 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7784
7785</div>
7786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7787<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7788<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7789<address>
7790 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7791 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7792 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7793 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7794
7795 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]7796 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7797 Last modified: $Date$
7798</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7799
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7800</body>
7801</html>