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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / db9cd76635220ebc6451069667e9aaaacb4fc455 / . / 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
1020 should be zero-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates to the code generator that the parameter or return value
1025 should be sign-extended to a 32-bit value by the caller (for a parameter)
1026 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates that this parameter or return value should be treated in a
1030 special target-dependent fashion during while emitting code for a function
1031 call or return (usually, by putting it in a register as opposed to memory,
1032 though some targets use it to distinguish between two different kinds of
1033 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1034
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1035 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1036 <dd><p>This indicates that the pointer parameter should really be passed by
1037 value to the function. The attribute implies that a hidden copy of the
1038 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 is made between the caller and the callee, so the callee is unable to
1040 modify the value in the callee. This attribute is only valid on LLVM
1041 pointer arguments. It is generally used to pass structs and arrays by
1042 value, but is also valid on pointers to scalars. The copy is considered
1043 to belong to the caller not the callee (for example,
1044 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1045 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1046 values.</p>
1047
1048 <p>The byval attribute also supports specifying an alignment with
1049 the align attribute. It indicates the alignment of the stack slot to
1050 form and the known alignment of the pointer specified to the call site. If
1051 the alignment is not specified, then the code generator makes a
1052 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1053
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1054 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This indicates that the pointer parameter specifies the address of a
1056 structure that is the return value of the function in the source program.
1057 This pointer must be guaranteed by the caller to be valid: loads and
1058 stores to the structure may be assumed by the callee to not to trap. This
1059 may only be applied to the first parameter. This is not a valid attribute
1060 for return values. </dd>
1061
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1062 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1063 <dd>This indicates that pointer values
1064 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1065 value do not alias pointer values which are not <i>based</i> on it,
1066 ignoring certain "irrelevant" dependencies.
1067 For a call to the parent function, dependencies between memory
1068 references from before or after the call and from those during the call
1069 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1070 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1071 The caller shares the responsibility with the callee for ensuring that
1072 these requirements are met.
1073 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1074 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1075<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1076 Note that this definition of <tt>noalias</tt> is intentionally
1077 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1078 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1079<br>
1080 For function return values, C99's <tt>restrict</tt> is not meaningful,
1081 while LLVM's <tt>noalias</tt> is.
1082 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1083
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1084 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1085 <dd>This indicates that the callee does not make any copies of the pointer
1086 that outlive the callee itself. This is not a valid attribute for return
1087 values.</dd>
1088
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1089 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This indicates that the pointer parameter can be excised using the
1091 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1092 attribute for return values.</dd>
1093</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1094
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1095</div>
1096
1097<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1098<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1099 <a name="gc">Garbage Collector Names</a>
1100</div>
1101
1102<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1103
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104<p>Each function may specify a garbage collector name, which is simply a
1105 string:</p>
1106
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1107<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1108define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1109</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1110
1111<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112 collector which will cause the compiler to alter its output in order to
1113 support the named garbage collection algorithm.</p>
1114
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1115</div>
1116
1117<!-- ======================================================================= -->
1118<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1119 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1120</div>
1121
1122<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1124<p>Function attributes are set to communicate additional information about a
1125 function. Function attributes are considered to be part of the function, not
1126 of the function type, so functions with different parameter attributes can
1127 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1128
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1129<p>Function attributes are simple keywords that follow the type specified. If
1130 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1131
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1132<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1133define void @f() noinline { ... }
1134define void @f() alwaysinline { ... }
1135define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1136define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1137</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1138
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1139<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1140 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1141 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1142 the backend should forcibly align the stack pointer. Specify the
1143 desired alignment, which must be a power of two, in parentheses.
1144
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1145 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1146 <dd>This attribute indicates that the inliner should attempt to inline this
1147 function into callers whenever possible, ignoring any active inlining size
1148 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1149
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1150 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1151 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1152 meaning the function can be patched and/or hooked even while it is
1153 loaded into memory. On x86, the function prologue will be preceded
1154 by six bytes of padding and will begin with a two-byte instruction.
1155 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1156 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1157
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1158 <dt><tt><b>inlinehint</b></tt></dt>
1159 <dd>This attribute indicates that the source code contained a hint that inlining
1160 this function is desirable (such as the "inline" keyword in C/C++). It
1161 is just a hint; it imposes no requirements on the inliner.</dd>
1162
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1163 <dt><tt><b>naked</b></tt></dt>
1164 <dd>This attribute disables prologue / epilogue emission for the function.
1165 This can have very system-specific consequences.</dd>
1166
1167 <dt><tt><b>noimplicitfloat</b></tt></dt>
1168 <dd>This attributes disables implicit floating point instructions.</dd>
1169
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the inliner should never inline this
1172 function in any situation. This attribute may not be used together with
1173 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1174
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1175 <dt><tt><b>noredzone</b></tt></dt>
1176 <dd>This attribute indicates that the code generator should not use a red
1177 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1178
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1179 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1180 <dd>This function attribute indicates that the function never returns
1181 normally. This produces undefined behavior at runtime if the function
1182 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1183
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1184 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1185 <dd>This function attribute indicates that the function never returns with an
1186 unwind or exceptional control flow. If the function does unwind, its
1187 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1188
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1189 <dt><tt><b>optsize</b></tt></dt>
1190 <dd>This attribute suggests that optimization passes and code generator passes
1191 make choices that keep the code size of this function low, and otherwise
1192 do optimizations specifically to reduce code size.</dd>
1193
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This attribute indicates that the function computes its result (or decides
1196 to unwind an exception) based strictly on its arguments, without
1197 dereferencing any pointer arguments or otherwise accessing any mutable
1198 state (e.g. memory, control registers, etc) visible to caller functions.
1199 It does not write through any pointer arguments
1200 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1201 changes any state visible to callers. This means that it cannot unwind
1202 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1203 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1204
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This attribute indicates that the function does not write through any
1207 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1208 arguments) or otherwise modify any state (e.g. memory, control registers,
1209 etc) visible to caller functions. It may dereference pointer arguments
1210 and read state that may be set in the caller. A readonly function always
1211 returns the same value (or unwinds an exception identically) when called
1212 with the same set of arguments and global state. It cannot unwind an
1213 exception by calling the <tt>C++</tt> exception throwing methods, but may
1214 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1215
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1216 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <dd>This attribute indicates that the function should emit a stack smashing
1218 protector. It is in the form of a "canary"&mdash;a random value placed on
1219 the stack before the local variables that's checked upon return from the
1220 function to see if it has been overwritten. A heuristic is used to
1221 determine if a function needs stack protectors or not.<br>
1222<br>
1223 If a function that has an <tt>ssp</tt> attribute is inlined into a
1224 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1225 function will have an <tt>ssp</tt> attribute.</dd>
1226
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1227 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1228 <dd>This attribute indicates that the function should <em>always</em> emit a
1229 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1230 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1231<br>
1232 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1233 function that doesn't have an <tt>sspreq</tt> attribute or which has
1234 an <tt>ssp</tt> attribute, then the resulting function will have
1235 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1236</dl>
1237
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1238</div>
1239
1240<!-- ======================================================================= -->
1241<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1242 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1243</div>
1244
1245<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1246
1247<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1248 the GCC "file scope inline asm" blocks. These blocks are internally
1249 concatenated by LLVM and treated as a single unit, but may be separated in
1250 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1251
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1252<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1253module asm "inline asm code goes here"
1254module asm "more can go here"
1255</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1256
1257<p>The strings can contain any character by escaping non-printable characters.
1258 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]1259 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1260
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261<p>The inline asm code is simply printed to the machine code .s file when
1262 assembly code is generated.</p>
1263
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1264</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1265
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1266<!-- ======================================================================= -->
1267<div class="doc_subsection">
1268 <a name="datalayout">Data Layout</a>
1269</div>
1270
1271<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1272
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1273<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 data is to be laid out in memory. The syntax for the data layout is
1275 simply:</p>
1276
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1277<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1278target datalayout = "<i>layout specification</i>"
1279</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1280
1281<p>The <i>layout specification</i> consists of a list of specifications
1282 separated by the minus sign character ('-'). Each specification starts with
1283 a letter and may include other information after the letter to define some
1284 aspect of the data layout. The specifications accepted are as follows:</p>
1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286<dl>
1287 <dt><tt>E</tt></dt>
1288 <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]1289 bits with the most significance have the lowest address location.</dd>
1290
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1291 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1292 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1293 the bits with the least significance have the lowest address
1294 location.</dd>
1295
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1296 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1297 <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]1298 <i>preferred</i> alignments. All sizes are in bits. Specifying
1299 the <i>pref</i> alignment is optional. If omitted, the
1300 preceding <tt>:</tt> should be omitted too.</dd>
1301
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1302 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1303 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1305
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1306 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1307 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1308 <i>size</i>.</dd>
1309
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1310 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1311 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1312 <i>size</i>. Only values of <i>size</i> that are supported by the target
1313 will work. 32 (float) and 64 (double) are supported on all targets;
1314 80 or 128 (different flavors of long double) are also supported on some
1315 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1318 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 <i>size</i>.</dd>
1320
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1321 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1322 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1323 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1324
1325 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1326 <dd>This specifies a set of native integer widths for the target CPU
1327 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1328 "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]1329 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1330 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1334 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1335 specifications in the <tt>datalayout</tt> keyword. The default specifications
1336 are given in this list:</p>
1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338<ul>
1339 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1340 <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]1341 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1342 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1343 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1344 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1345 <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]1346 alignment of 64-bits</li>
1347 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1348 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1349 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1350 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1351 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1352 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1353</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1354
1355<p>When LLVM is determining the alignment for a given type, it uses the
1356 following rules:</p>
1357
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358<ol>
1359 <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]1360 specification is used.</li>
1361
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1362 <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]1363 smallest integer type that is larger than the bitwidth of the sought type
1364 is used. If none of the specifications are larger than the bitwidth then
1365 the the largest integer type is used. For example, given the default
1366 specifications above, the i7 type will use the alignment of i8 (next
1367 largest) while both i65 and i256 will use the alignment of i64 (largest
1368 specified).</li>
1369
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1370 <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]1371 largest vector type that is smaller than the sought vector type will be
1372 used as a fall back. This happens because &lt;128 x double&gt; can be
1373 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1374</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1375
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1377
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1378<!-- ======================================================================= -->
1379<div class="doc_subsection">
1380 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1381</div>
1382
1383<div class="doc_text">
1384
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1385<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1386with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1387is undefined. Pointer values are associated with address ranges
1388according to the following rules:</p>
1389
1390<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1391 <li>A pointer value is associated with the addresses associated with
1392 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1393 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1394 range of the variable's storage.</li>
1395 <li>The result value of an allocation instruction is associated with
1396 the address range of the allocated storage.</li>
1397 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1398 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1399 <li>An integer constant other than zero or a pointer value returned
1400 from a function not defined within LLVM may be associated with address
1401 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1402 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1403 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1404</ul>
1405
1406<p>A pointer value is <i>based</i> on another pointer value according
1407 to the following rules:</p>
1408
1409<ul>
1410 <li>A pointer value formed from a
1411 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1412 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1413 <li>The result value of a
1414 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1415 of the <tt>bitcast</tt>.</li>
1416 <li>A pointer value formed by an
1417 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1418 pointer values that contribute (directly or indirectly) to the
1419 computation of the pointer's value.</li>
1420 <li>The "<i>based</i> on" relationship is transitive.</li>
1421</ul>
1422
1423<p>Note that this definition of <i>"based"</i> is intentionally
1424 similar to the definition of <i>"based"</i> in C99, though it is
1425 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426
1427<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1428<tt><a href="#i_load">load</a></tt> merely indicates the size and
1429alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1430interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1431<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1432and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1433
1434<p>Consequently, type-based alias analysis, aka TBAA, aka
1435<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1436LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1437additional information which specialized optimization passes may use
1438to implement type-based alias analysis.</p>
1439
1440</div>
1441
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1442<!-- ======================================================================= -->
1443<div class="doc_subsection">
1444 <a name="volatile">Volatile Memory Accesses</a>
1445</div>
1446
1447<div class="doc_text">
1448
1449<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1450href="#i_store"><tt>store</tt></a>s, and <a
1451href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1452The optimizers must not change the number of volatile operations or change their
1453order of execution relative to other volatile operations. The optimizers
1454<i>may</i> change the order of volatile operations relative to non-volatile
1455operations. This is not Java's "volatile" and has no cross-thread
1456synchronization behavior.</p>
1457
1458</div>
1459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1462<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1466<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1467 intermediate representation. Being typed enables a number of optimizations
1468 to be performed on the intermediate representation directly, without having
1469 to do extra analyses on the side before the transformation. A strong type
1470 system makes it easier to read the generated code and enables novel analyses
1471 and transformations that are not feasible to perform on normal three address
1472 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1473
1474</div>
1475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1476<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1477<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1479
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1480<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1481
1482<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1483
1484<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1485 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1486 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1489 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
1491 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492 <td><a href="#t_floating">floating point</a></td>
1493 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1494 </tr>
1495 <tr>
1496 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497 <td><a href="#t_integer">integer</a>,
1498 <a href="#t_floating">floating point</a>,
1499 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1500 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1501 <a href="#t_struct">structure</a>,
1502 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1503 <a href="#t_label">label</a>,
1504 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1505 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1506 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1507 <tr>
1508 <td><a href="#t_primitive">primitive</a></td>
1509 <td><a href="#t_label">label</a>,
1510 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1511 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1512 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1513 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1514 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1515 </tr>
1516 <tr>
1517 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1518 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519 <a href="#t_function">function</a>,
1520 <a href="#t_pointer">pointer</a>,
1521 <a href="#t_struct">structure</a>,
1522 <a href="#t_pstruct">packed structure</a>,
1523 <a href="#t_vector">vector</a>,
1524 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1525 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1527 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1530<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1531 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1532 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1534</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1536<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1537<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1538
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1540
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1541<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1542 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1543
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1544</div>
1545
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1546<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1547<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1548
1549<div class="doc_text">
1550
1551<h5>Overview:</h5>
1552<p>The integer type is a very simple type that simply specifies an arbitrary
1553 bit width for the integer type desired. Any bit width from 1 bit to
1554 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1555
1556<h5>Syntax:</h5>
1557<pre>
1558 iN
1559</pre>
1560
1561<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1562 value.</p>
1563
1564<h5>Examples:</h5>
1565<table class="layout">
1566 <tr class="layout">
1567 <td class="left"><tt>i1</tt></td>
1568 <td class="left">a single-bit integer.</td>
1569 </tr>
1570 <tr class="layout">
1571 <td class="left"><tt>i32</tt></td>
1572 <td class="left">a 32-bit integer.</td>
1573 </tr>
1574 <tr class="layout">
1575 <td class="left"><tt>i1942652</tt></td>
1576 <td class="left">a really big integer of over 1 million bits.</td>
1577 </tr>
1578</table>
1579
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1580</div>
1581
1582<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1583<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1584
1585<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1586
1587<table>
1588 <tbody>
1589 <tr><th>Type</th><th>Description</th></tr>
1590 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1591 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1592 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1593 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1594 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1595 </tbody>
1596</table>
1597
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1598</div>
1599
1600<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1601<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1602
1603<div class="doc_text">
1604
1605<h5>Overview:</h5>
1606<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>
1607
1608<h5>Syntax:</h5>
1609<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1610 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1611</pre>
1612
1613</div>
1614
1615<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1616<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1617
1618<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1619
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1620<h5>Overview:</h5>
1621<p>The void type does not represent any value and has no size.</p>
1622
1623<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1624<pre>
1625 void
1626</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1627
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1628</div>
1629
1630<!-- _______________________________________________________________________ -->
1631<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1632
1633<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1634
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1635<h5>Overview:</h5>
1636<p>The label type represents code labels.</p>
1637
1638<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1639<pre>
1640 label
1641</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1642
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1643</div>
1644
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
1646<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1647
1648<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1649
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1650<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1651<p>The metadata type represents embedded metadata. No derived types may be
1652 created from metadata except for <a href="#t_function">function</a>
1653 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1654
1655<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1656<pre>
1657 metadata
1658</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1659
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1660</div>
1661
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1662
1663<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1664<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1665
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1666<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1667
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1668<p>The real power in LLVM comes from the derived types in the system. This is
1669 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1670 useful types. Each of these types contain one or more element types which
1671 may be a primitive type, or another derived type. For example, it is
1672 possible to have a two dimensional array, using an array as the element type
1673 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1674
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1675
1676</div>
1677
1678<!-- _______________________________________________________________________ -->
1679<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1680
1681<div class="doc_text">
1682
1683<p>Aggregate Types are a subset of derived types that can contain multiple
1684 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1685 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1686 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1687
1688</div>
1689
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1690<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1696<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697 sequentially in memory. The array type requires a size (number of elements)
1698 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1699
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1700<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1701<pre>
1702 [&lt;# elements&gt; x &lt;elementtype&gt;]
1703</pre>
1704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1705<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1706 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1707
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1708<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1709<table class="layout">
1710 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1711 <td class="left"><tt>[40 x i32]</tt></td>
1712 <td class="left">Array of 40 32-bit integer values.</td>
1713 </tr>
1714 <tr class="layout">
1715 <td class="left"><tt>[41 x i32]</tt></td>
1716 <td class="left">Array of 41 32-bit integer values.</td>
1717 </tr>
1718 <tr class="layout">
1719 <td class="left"><tt>[4 x i8]</tt></td>
1720 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1721 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1722</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1723<p>Here are some examples of multidimensional arrays:</p>
1724<table class="layout">
1725 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1726 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1727 <td class="left">3x4 array of 32-bit integer values.</td>
1728 </tr>
1729 <tr class="layout">
1730 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1731 <td class="left">12x10 array of single precision floating point values.</td>
1732 </tr>
1733 <tr class="layout">
1734 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1735 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1736 </tr>
1737</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1738
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1739<p>There is no restriction on indexing beyond the end of the array implied by
1740 a static type (though there are restrictions on indexing beyond the bounds
1741 of an allocated object in some cases). This means that single-dimension
1742 'variable sized array' addressing can be implemented in LLVM with a zero
1743 length array type. An implementation of 'pascal style arrays' in LLVM could
1744 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1745
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1746</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1747
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1748<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1749<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1750
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1754<p>The function type can be thought of as a function signature. It consists of
1755 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]1756 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1757
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1759<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1760 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1761</pre>
1762
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1763<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]1764 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1765 which indicates that the function takes a variable number of arguments.
1766 Variable argument functions can access their arguments with
1767 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1768 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1769 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1770
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1772<table class="layout">
1773 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1774 <td class="left"><tt>i32 (i32)</tt></td>
1775 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1776 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1777 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1778 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1779 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1780 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1781 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1782 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1783 </td>
1784 </tr><tr class="layout">
1785 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1786 <td class="left">A vararg function that takes at least one
1787 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1788 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1789 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1790 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1791 </tr><tr class="layout">
1792 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1793 <td class="left">A function taking an <tt>i32</tt>, returning a
1794 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1795 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1796 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1797</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1804<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807<p>The structure type is used to represent a collection of data members together
1808 in memory. The packing of the field types is defined to match the ABI of the
1809 underlying processor. The elements of a structure may be any type that has a
1810 size.</p>
1811
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1812<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1813 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1814 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1815 Structures in registers are accessed using the
1816 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1817 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1819<pre>
1820 { &lt;type list&gt; }
1821</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1824<table class="layout">
1825 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1826 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1827 <td class="left">A triple of three <tt>i32</tt> values</td>
1828 </tr><tr class="layout">
1829 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1830 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1831 second element is a <a href="#t_pointer">pointer</a> to a
1832 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1833 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1834 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1835</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1837</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1840<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1841</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1843<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1844
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1845<h5>Overview:</h5>
1846<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1847 together in memory. There is no padding between fields. Further, the
1848 alignment of a packed structure is 1 byte. The elements of a packed
1849 structure may be any type that has a size.</p>
1850
1851<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1852 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1853 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1854
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1856<pre>
1857 &lt; { &lt;type list&gt; } &gt;
1858</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1859
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1860<h5>Examples:</h5>
1861<table class="layout">
1862 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1863 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1864 <td class="left">A triple of three <tt>i32</tt> values</td>
1865 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1866 <td class="left">
1867<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1868 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1869 second element is a <a href="#t_pointer">pointer</a> to a
1870 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1871 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1872 </tr>
1873</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1874
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1875</div>
1876
1877<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880<div class="doc_text">
1881
1882<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1883<p>The pointer type is used to specify memory locations.
1884 Pointers are commonly used to reference objects in memory.</p>
1885
1886<p>Pointer types may have an optional address space attribute defining the
1887 numbered address space where the pointed-to object resides. The default
1888 address space is number zero. The semantics of non-zero address
1889 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1890
1891<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1892 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1893
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1894<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1895<pre>
1896 &lt;type&gt; *
1897</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1898
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1899<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1900<table class="layout">
1901 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1902 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1903 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1904 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1905 </tr>
1906 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1907 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1908 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1909 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1910 <tt>i32</tt>.</td>
1911 </tr>
1912 <tr class="layout">
1913 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1914 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1915 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1916 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1917</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1920
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1922<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1924<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1925
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1926<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927<p>A vector type is a simple derived type that represents a vector of elements.
1928 Vector types are used when multiple primitive data are operated in parallel
1929 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1930 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1931 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1932
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1933<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1934<pre>
1935 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1936</pre>
1937
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1938<p>The number of elements is a constant integer value larger than 0; elementtype
1939 may be any integer or floating point type. Vectors of size zero are not
1940 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1941
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1945 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1946 <td class="left">Vector of 4 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1950 <td class="left">Vector of 8 32-bit floating-point values.</td>
1951 </tr>
1952 <tr class="layout">
1953 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1954 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
1956</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1958</div>
1959
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960<!-- _______________________________________________________________________ -->
1961<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1962<div class="doc_text">
1963
1964<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1965<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1966 corresponds (for example) to the C notion of a forward declared structure
1967 type. In LLVM, opaque types can eventually be resolved to any type (not just
1968 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1969
1970<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971<pre>
1972 opaque
1973</pre>
1974
1975<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1976<table class="layout">
1977 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1978 <td class="left"><tt>opaque</tt></td>
1979 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1980 </tr>
1981</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1982
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1983</div>
1984
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1985<!-- ======================================================================= -->
1986<div class="doc_subsection">
1987 <a name="t_uprefs">Type Up-references</a>
1988</div>
1989
1990<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1991
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1992<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993<p>An "up reference" allows you to refer to a lexically enclosing type without
1994 requiring it to have a name. For instance, a structure declaration may
1995 contain a pointer to any of the types it is lexically a member of. Example
1996 of up references (with their equivalent as named type declarations)
1997 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1998
1999<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2000 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2001 { \2 }* %y = type { %y }*
2002 \1* %z = type %z*
2003</pre>
2004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2005<p>An up reference is needed by the asmprinter for printing out cyclic types
2006 when there is no declared name for a type in the cycle. Because the
2007 asmprinter does not want to print out an infinite type string, it needs a
2008 syntax to handle recursive types that have no names (all names are optional
2009 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2010
2011<h5>Syntax:</h5>
2012<pre>
2013 \&lt;level&gt;
2014</pre>
2015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2016<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]2017
2018<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2019<table class="layout">
2020 <tr class="layout">
2021 <td class="left"><tt>\1*</tt></td>
2022 <td class="left">Self-referential pointer.</td>
2023 </tr>
2024 <tr class="layout">
2025 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2026 <td class="left">Recursive structure where the upref refers to the out-most
2027 structure.</td>
2028 </tr>
2029</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2030
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2031</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2032
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2033<!-- *********************************************************************** -->
2034<div class="doc_section"> <a name="constants">Constants</a> </div>
2035<!-- *********************************************************************** -->
2036
2037<div class="doc_text">
2038
2039<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2040 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042</div>
2043
2044<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2045<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046
2047<div class="doc_text">
2048
2049<dl>
2050 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2051 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2052 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2055 <dd>Standard integers (such as '4') are constants of
2056 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2057 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2058
2059 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2060 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2061 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2062 notation (see below). The assembler requires the exact decimal value of a
2063 floating-point constant. For example, the assembler accepts 1.25 but
2064 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2065 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2066
2067 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2068 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2069 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2070</dl>
2071
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2072<p>The one non-intuitive notation for constants is the hexadecimal form of
2073 floating point constants. For example, the form '<tt>double
2074 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2075 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2076 constants are required (and the only time that they are generated by the
2077 disassembler) is when a floating point constant must be emitted but it cannot
2078 be represented as a decimal floating point number in a reasonable number of
2079 digits. For example, NaN's, infinities, and other special values are
2080 represented in their IEEE hexadecimal format so that assembly and disassembly
2081 do not cause any bits to change in the constants.</p>
2082
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2083<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2084 represented using the 16-digit form shown above (which matches the IEEE754
2085 representation for double); float values must, however, be exactly
2086 representable as IEE754 single precision. Hexadecimal format is always used
2087 for long double, and there are three forms of long double. The 80-bit format
2088 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2089 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2090 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2091 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2092 currently supported target uses this format. Long doubles will only work if
2093 they match the long double format on your target. All hexadecimal formats
2094 are big-endian (sign bit at the left).</p>
2095
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2096<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2100<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2101<a name="aggregateconstants"></a> <!-- old anchor -->
2102<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2103</div>
2104
2105<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2106
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2107<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2109
2110<dl>
2111 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2112 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113 type definitions (a comma separated list of elements, surrounded by braces
2114 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2115 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2116 Structure constants must have <a href="#t_struct">structure type</a>, and
2117 the number and types of elements must match those specified by the
2118 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2119
2120 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2121 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2122 definitions (a comma separated list of elements, surrounded by square
2123 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2124 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2125 the number and types of elements must match those specified by the
2126 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2127
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2128 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2129 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2130 definitions (a comma separated list of elements, surrounded by
2131 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2132 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2133 have <a href="#t_vector">vector type</a>, and the number and types of
2134 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2135
2136 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2138 value to zero of <em>any</em> type, including scalar and
2139 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2140 This is often used to avoid having to print large zero initializers
2141 (e.g. for large arrays) and is always exactly equivalent to using explicit
2142 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2143
2144 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2145 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2146 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2147 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2148 be interpreted as part of the instruction stream, metadata is a place to
2149 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2150</dl>
2151
2152</div>
2153
2154<!-- ======================================================================= -->
2155<div class="doc_subsection">
2156 <a name="globalconstants">Global Variable and Function Addresses</a>
2157</div>
2158
2159<div class="doc_text">
2160
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2161<p>The addresses of <a href="#globalvars">global variables</a>
2162 and <a href="#functionstructure">functions</a> are always implicitly valid
2163 (link-time) constants. These constants are explicitly referenced when
2164 the <a href="#identifiers">identifier for the global</a> is used and always
2165 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2166 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2167
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2168<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2169@X = global i32 17
2170@Y = global i32 42
2171@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2172</pre>
2173
2174</div>
2175
2176<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2177<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2178<div class="doc_text">
2179
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2180<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]2181 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2182 Undefined values may be of any type (other than '<tt>label</tt>'
2183 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2185<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186 program is well defined no matter what value is used. This gives the
2187 compiler more freedom to optimize. Here are some examples of (potentially
2188 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2189
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2190
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2191<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2192 %A = add %X, undef
2193 %B = sub %X, undef
2194 %C = xor %X, undef
2195Safe:
2196 %A = undef
2197 %B = undef
2198 %C = undef
2199</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2200
2201<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]2202 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]2203
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2204<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2205 %A = or %X, undef
2206 %B = and %X, undef
2207Safe:
2208 %A = -1
2209 %B = 0
2210Unsafe:
2211 %A = undef
2212 %B = undef
2213</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2214
2215<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2216 For example, if <tt>%X</tt> has a zero bit, then the output of the
2217 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2218 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2219 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2220 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2221 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2222 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2223 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2224
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2225<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2226 %A = select undef, %X, %Y
2227 %B = select undef, 42, %Y
2228 %C = select %X, %Y, undef
2229Safe:
2230 %A = %X (or %Y)
2231 %B = 42 (or %Y)
2232 %C = %Y
2233Unsafe:
2234 %A = undef
2235 %B = undef
2236 %C = undef
2237</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2238
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2239<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2240 branch) conditions can go <em>either way</em>, but they have to come from one
2241 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2242 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2243 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2244 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2245 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2246 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2247
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2248<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2250
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2251 %B = undef
2252 %C = xor %B, %B
2253
2254 %D = undef
2255 %E = icmp lt %D, 4
2256 %F = icmp gte %D, 4
2257
2258Safe:
2259 %A = undef
2260 %B = undef
2261 %C = undef
2262 %D = undef
2263 %E = undef
2264 %F = undef
2265</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2266
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2267<p>This example points out that two '<tt>undef</tt>' operands are not
2268 necessarily the same. This can be surprising to people (and also matches C
2269 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2270 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2271 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2272 its value over its "live range". This is true because the variable doesn't
2273 actually <em>have a live range</em>. Instead, the value is logically read
2274 from arbitrary registers that happen to be around when needed, so the value
2275 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2276 need to have the same semantics or the core LLVM "replace all uses with"
2277 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2278
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2279<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2280 %A = fdiv undef, %X
2281 %B = fdiv %X, undef
2282Safe:
2283 %A = undef
2284b: unreachable
2285</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2286
2287<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2288 value</em> and <em>undefined behavior</em>. An undefined value (like
2289 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2290 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2291 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2292 defined on SNaN's. However, in the second example, we can make a more
2293 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2294 arbitrary value, we are allowed to assume that it could be zero. Since a
2295 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2296 the operation does not execute at all. This allows us to delete the divide and
2297 all code after it. Because the undefined operation "can't happen", the
2298 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2299
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2300<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2301a: store undef -> %X
2302b: store %X -> undef
2303Safe:
2304a: &lt;deleted&gt;
2305b: unreachable
2306</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2307
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2308<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2309 undefined value can be assumed to not have any effect; we can assume that the
2310 value is overwritten with bits that happen to match what was already there.
2311 However, a store <em>to</em> an undefined location could clobber arbitrary
2312 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2313
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2314</div>
2315
2316<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2317<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2318<div class="doc_text">
2319
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2320<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2321 instead of representing an unspecified bit pattern, they represent the
2322 fact that an instruction or constant expression which cannot evoke side
2323 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2324 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2325
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2326<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]2327 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2328 <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]2329
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2330<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2332<ul>
2333<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2334 their operands.</li>
2335
2336<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2337 to their dynamic predecessor basic block.</li>
2338
2339<li>Function arguments depend on the corresponding actual argument values in
2340 the dynamic callers of their functions.</li>
2341
2342<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2343 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2344 control back to them.</li>
2345
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2346<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2347 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2348 or exception-throwing call instructions that dynamically transfer control
2349 back to them.</li>
2350
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2351<li>Non-volatile loads and stores depend on the most recent stores to all of the
2352 referenced memory addresses, following the order in the IR
2353 (including loads and stores implied by intrinsics such as
2354 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2355
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2356<!-- TODO: In the case of multiple threads, this only applies if the store
2357 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2358
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2359<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2361<li>An instruction with externally visible side effects depends on the most
2362 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2363 the order in the IR. (This includes
2364 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2365
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2366<li>An instruction <i>control-depends</i> on a
2367 <a href="#terminators">terminator instruction</a>
2368 if the terminator instruction has multiple successors and the instruction
2369 is always executed when control transfers to one of the successors, and
2370 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2371
2372<li>Dependence is transitive.</li>
2373
2374</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2375
2376<p>Whenever a trap value is generated, all values which depend on it evaluate
2377 to trap. If they have side effects, the evoke their side effects as if each
2378 operand with a trap value were undef. If they have externally-visible side
2379 effects, the behavior is undefined.</p>
2380
2381<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2382
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2383<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2384entry:
2385 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2386 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2387 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2388 store i32 0, i32* %trap_yet_again ; undefined behavior
2389
2390 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2391 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2392
2393 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2394
2395 %narrowaddr = bitcast i32* @g to i16*
2396 %wideaddr = bitcast i32* @g to i64*
2397 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2398 %trap4 = load i64* %widaddr ; Returns a trap value.
2399
2400 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2401 %br i1 %cmp, %true, %end ; Branch to either destination.
2402
2403true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2404 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2405 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2406 br label %end
2407
2408end:
2409 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2410 ; Both edges into this PHI are
2411 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2412 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2413
2414 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2415 ; so this is defined (ignoring earlier
2416 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2417</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2418
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2419</div>
2420
2421<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2422<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2423 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2424<div class="doc_text">
2425
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2426<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2427
2428<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2429 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2430 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2431
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2432<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2433 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2434 comparisons against null. Pointer equality tests between labels addresses
2435 results in undefined behavior &mdash; though, again, comparison against null
2436 is ok, and no label is equal to the null pointer. This may be passed around
2437 as an opaque pointer sized value as long as the bits are not inspected. This
2438 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2439 long as the original value is reconstituted before the <tt>indirectbr</tt>
2440 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2441
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2442<p>Finally, some targets may provide defined semantics when using the value as
2443 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2444
2445</div>
2446
2447
2448<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2449<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2450</div>
2451
2452<div class="doc_text">
2453
2454<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2455 to be used as constants. Constant expressions may be of
2456 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2457 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2458 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2459
2460<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2461 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Truncate a constant to another type. The bit size of CST must be larger
2463 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2464
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2465 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2466 <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]2467 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2468
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2469 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2470 <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]2471 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2472
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2473 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2474 <dd>Truncate a floating point constant to another floating point type. The
2475 size of CST must be larger than the size of TYPE. Both types must be
2476 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2477
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2478 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479 <dd>Floating point extend a constant to another type. The size of CST must be
2480 smaller or equal to the size of TYPE. Both types must be floating
2481 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2482
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2483 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2485 constant. TYPE must be a scalar or vector integer type. CST must be of
2486 scalar or vector floating point type. Both CST and TYPE must be scalars,
2487 or vectors of the same number of elements. If the value won't fit in the
2488 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2489
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2490 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2491 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2492 constant. TYPE must be a scalar or vector integer type. CST must be of
2493 scalar or vector floating point type. Both CST and TYPE must be scalars,
2494 or vectors of the same number of elements. If the value won't fit in the
2495 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2496
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2497 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2498 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector floating point type. CST must be
2500 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2501 vectors of the same number of elements. If the value won't fit in the
2502 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector floating point type. CST must be
2507 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2508 vectors of the same number of elements. If the value won't fit in the
2509 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2510
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2512 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2513 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2514 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2515 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2516
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2517 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2518 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2519 type. CST must be of integer type. The CST value is zero extended,
2520 truncated, or unchanged to make it fit in a pointer size. This one is
2521 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2522
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2523 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2524 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2525 are the same as those for the <a href="#i_bitcast">bitcast
2526 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2527
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2528 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2529 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2530 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2531 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2532 instruction, the index list may have zero or more indexes, which are
2533 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2534
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2535 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2537
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2538 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2539 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2540
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2541 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2542 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2543
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2544 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2545 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2546 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2547
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2549 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2550 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2551
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2552 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2554 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2555
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2556 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2557 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2558 constants. The index list is interpreted in a similar manner as indices in
2559 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2560 index value must be specified.</dd>
2561
2562 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2563 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2564 constants. The index list is interpreted in a similar manner as indices in
2565 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2566 index value must be specified.</dd>
2567
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2568 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2569 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2570 be any of the <a href="#binaryops">binary</a>
2571 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2572 on operands are the same as those for the corresponding instruction
2573 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2574</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2575
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2576</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2578<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2579<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2580<!-- *********************************************************************** -->
2581
2582<!-- ======================================================================= -->
2583<div class="doc_subsection">
2584<a name="inlineasm">Inline Assembler Expressions</a>
2585</div>
2586
2587<div class="doc_text">
2588
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2589<p>LLVM supports inline assembler expressions (as opposed
2590 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2591 a special value. This value represents the inline assembler as a string
2592 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2593 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2594 expression has side effects, and a flag indicating whether the function
2595 containing the asm needs to align its stack conservatively. An example
2596 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2597
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2598<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2599i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2600</pre>
2601
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2602<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2603 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2604 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2605
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2606<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2607%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]2608</pre>
2609
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2610<p>Inline asms with side effects not visible in the constraint list must be
2611 marked as having side effects. This is done through the use of the
2612 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2613
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2614<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2615call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2616</pre>
2617
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2618<p>In some cases inline asms will contain code that will not work unless the
2619 stack is aligned in some way, such as calls or SSE instructions on x86,
2620 yet will not contain code that does that alignment within the asm.
2621 The compiler should make conservative assumptions about what the asm might
2622 contain and should generate its usual stack alignment code in the prologue
2623 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2624
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2625<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2626call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2627</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2628
2629<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2630 first.</p>
2631
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2632<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2633 documented here. Constraints on what can be done (e.g. duplication, moving,
2634 etc need to be documented). This is probably best done by reference to
2635 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2636</div>
2637
2638<div class="doc_subsubsection">
2639<a name="inlineasm_md">Inline Asm Metadata</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2645 attached to it that contains a list of constant integers. If present, the
2646 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2647 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2648 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2649 source code that produced it. For example:</p>
2650
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2651<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2652call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2653...
2654!42 = !{ i32 1234567 }
2655</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2656
2657<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]2658 IR. If the MDNode contains multiple constants, the code generator will use
2659 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]2660
2661</div>
2662
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2663<!-- ======================================================================= -->
2664<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2665 Strings</a>
2666</div>
2667
2668<div class="doc_text">
2669
2670<p>LLVM IR allows metadata to be attached to instructions in the program that
2671 can convey extra information about the code to the optimizers and code
2672 generator. One example application of metadata is source-level debug
2673 information. There are two metadata primitives: strings and nodes. All
2674 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2675 preceding exclamation point ('<tt>!</tt>').</p>
2676
2677<p>A metadata string is a string surrounded by double quotes. It can contain
2678 any character by escaping non-printable characters with "\xx" where "xx" is
2679 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2680
2681<p>Metadata nodes are represented with notation similar to structure constants
2682 (a comma separated list of elements, surrounded by braces and preceded by an
2683 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2684 10}</tt>". Metadata nodes can have any values as their operand.</p>
2685
2686<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2687 metadata nodes, which can be looked up in the module symbol table. For
2688 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2689
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2690<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2691 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2692
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2693 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2694 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2695 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2696
2697<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2698 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2699
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2700 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2701 %indvar.next = add i64 %indvar, 1, !dbg !21
2702 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2703</div>
2704
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2705
2706<!-- *********************************************************************** -->
2707<div class="doc_section">
2708 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2709</div>
2710<!-- *********************************************************************** -->
2711
2712<p>LLVM has a number of "magic" global variables that contain data that affect
2713code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2714of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2715section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2716by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2717
2718<!-- ======================================================================= -->
2719<div class="doc_subsection">
2720<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2721</div>
2722
2723<div class="doc_text">
2724
2725<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2726href="#linkage_appending">appending linkage</a>. This array contains a list of
2727pointers to global variables and functions which may optionally have a pointer
2728cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2729
2730<pre>
2731 @X = global i8 4
2732 @Y = global i32 123
2733
2734 @llvm.used = appending global [2 x i8*] [
2735 i8* @X,
2736 i8* bitcast (i32* @Y to i8*)
2737 ], section "llvm.metadata"
2738</pre>
2739
2740<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2741compiler, assembler, and linker are required to treat the symbol as if there is
2742a reference to the global that it cannot see. For example, if a variable has
2743internal linkage and no references other than that from the <tt>@llvm.used</tt>
2744list, it cannot be deleted. This is commonly used to represent references from
2745inline asms and other things the compiler cannot "see", and corresponds to
2746"attribute((used))" in GNU C.</p>
2747
2748<p>On some targets, the code generator must emit a directive to the assembler or
2749object file to prevent the assembler and linker from molesting the symbol.</p>
2750
2751</div>
2752
2753<!-- ======================================================================= -->
2754<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2755<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2756</div>
2757
2758<div class="doc_text">
2759
2760<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2761<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2762touching the symbol. On targets that support it, this allows an intelligent
2763linker to optimize references to the symbol without being impeded as it would be
2764by <tt>@llvm.used</tt>.</p>
2765
2766<p>This is a rare construct that should only be used in rare circumstances, and
2767should not be exposed to source languages.</p>
2768
2769</div>
2770
2771<!-- ======================================================================= -->
2772<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2773<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2774</div>
2775
2776<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2777<pre>
2778%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2779@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2780</pre>
2781<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.
2782</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2783
2784</div>
2785
2786<!-- ======================================================================= -->
2787<div class="doc_subsection">
2788<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2789</div>
2790
2791<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2792<pre>
2793%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2794@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2795</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2796
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2797<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.
2798</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2799
2800</div>
2801
2802
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2803<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2804<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2805<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2807<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2808
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809<p>The LLVM instruction set consists of several different classifications of
2810 instructions: <a href="#terminators">terminator
2811 instructions</a>, <a href="#binaryops">binary instructions</a>,
2812 <a href="#bitwiseops">bitwise binary instructions</a>,
2813 <a href="#memoryops">memory instructions</a>, and
2814 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2815
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2816</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2817
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2818<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2819<div class="doc_subsection"> <a name="terminators">Terminator
2820Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2821
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2822<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2825 in a program ends with a "Terminator" instruction, which indicates which
2826 block should be executed after the current block is finished. These
2827 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2828 control flow, not values (the one exception being the
2829 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2830
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2831<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2833 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2834 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2835 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2836 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2837 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2838 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2839
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2840</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2843<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2844Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2846<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2848<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2849<pre>
2850 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]2851 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2852</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2855<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2856 a value) from a function back to the caller.</p>
2857
2858<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2859 value and then causes control flow, and one that just causes control flow to
2860 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2863<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2864 return value. The type of the return value must be a
2865 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2867<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2868 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2869 value or a return value with a type that does not match its type, or if it
2870 has a void return type and contains a '<tt>ret</tt>' instruction with a
2871 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2872
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2873<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2875 the calling function's context. If the caller is a
2876 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2877 instruction after the call. If the caller was an
2878 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2879 the beginning of the "normal" destination block. If the instruction returns
2880 a value, that value shall set the call or invoke instruction's return
2881 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2884<pre>
2885 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2886 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2887 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]2888</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2889
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2890</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2891<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2892<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2893
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2894<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2897<pre>
2898 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]2899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2903 different basic block in the current function. There are two forms of this
2904 instruction, corresponding to a conditional branch and an unconditional
2905 branch.</p>
2906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2907<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2909 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2910 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2911 target.</p>
2912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2914<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2916 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2917 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2919<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2920<pre>
2921Test:
2922 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2923 br i1 %cond, label %IfEqual, label %IfUnequal
2924IfEqual:
2925 <a href="#i_ret">ret</a> i32 1
2926IfUnequal:
2927 <a href="#i_ret">ret</a> i32 0
2928</pre>
2929
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2930</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2933<div class="doc_subsubsection">
2934 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2935</div>
2936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2937<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2938
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2939<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2940<pre>
2941 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2942</pre>
2943
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2944<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2945<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]2946 several different places. It is a generalization of the '<tt>br</tt>'
2947 instruction, allowing a branch to occur to one of many possible
2948 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2950<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2953 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2954 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2955
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2956<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2957<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2958 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2959 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2960 transferred to the corresponding destination; otherwise, control flow is
2961 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2962
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2963<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2964<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965 <tt>switch</tt> instruction, this instruction may be code generated in
2966 different ways. For example, it could be generated as a series of chained
2967 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2968
2969<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2970<pre>
2971 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2972 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2973 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2974
2975 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2976 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2977
2978 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2979 switch i32 %val, label %otherwise [ i32 0, label %onzero
2980 i32 1, label %onone
2981 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2982</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2983
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2984</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2985
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2986
2987<!-- _______________________________________________________________________ -->
2988<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2989 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2990</div>
2991
2992<div class="doc_text">
2993
2994<h5>Syntax:</h5>
2995<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2996 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]2997</pre>
2998
2999<h5>Overview:</h5>
3000
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3001<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3002 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3003 "<tt>address</tt>". Address must be derived from a <a
3004 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3005
3006<h5>Arguments:</h5>
3007
3008<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3009 rest of the arguments indicate the full set of possible destinations that the
3010 address may point to. Blocks are allowed to occur multiple times in the
3011 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3012
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3013<p>This destination list is required so that dataflow analysis has an accurate
3014 understanding of the CFG.</p>
3015
3016<h5>Semantics:</h5>
3017
3018<p>Control transfers to the block specified in the address argument. All
3019 possible destination blocks must be listed in the label list, otherwise this
3020 instruction has undefined behavior. This implies that jumps to labels
3021 defined in other functions have undefined behavior as well.</p>
3022
3023<h5>Implementation:</h5>
3024
3025<p>This is typically implemented with a jump through a register.</p>
3026
3027<h5>Example:</h5>
3028<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3029 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3030</pre>
3031
3032</div>
3033
3034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3035<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3036<div class="doc_subsubsection">
3037 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3038</div>
3039
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3040<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3041
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3042<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3043<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3044 &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]3045 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3046</pre>
3047
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3048<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3050 function, with the possibility of control flow transfer to either the
3051 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3052 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3053 control flow will return to the "normal" label. If the callee (or any
3054 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3055 instruction, control is interrupted and continued at the dynamically nearest
3056 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3057
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3058<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3059<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3061<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3063 convention</a> the call should use. If none is specified, the call
3064 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3065
3066 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3068 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3069
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070 <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]3071 function value being invoked. In most cases, this is a direct function
3072 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3073 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3074
3075 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3076 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3077
3078 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3079 signature argument types and parameter attributes. All arguments must be
3080 of <a href="#t_firstclass">first class</a> type. If the function
3081 signature indicates the function accepts a variable number of arguments,
3082 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3083
3084 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3086
3087 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3089
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3090 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3091 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3092 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3093</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3094
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3096<p>This instruction is designed to operate as a standard
3097 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3098 primary difference is that it establishes an association with a label, which
3099 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3100
3101<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3102 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3103 exception. Additionally, this is important for implementation of
3104 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3105
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3106<p>For the purposes of the SSA form, the definition of the value returned by the
3107 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3108 block to the "normal" label. If the callee unwinds then no return value is
3109 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3110
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3111<p>Note that the code generator does not yet completely support unwind, and
3112that the invoke/unwind semantics are likely to change in future versions.</p>
3113
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3114<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3115<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3116 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3117 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3118 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3119 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3120</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3122</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3123
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3124<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3125
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3126<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3127Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3128
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3129<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3130
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3131<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3132<pre>
3133 unwind
3134</pre>
3135
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3136<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3137<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3138 at the first callee in the dynamic call stack which used
3139 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3140 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3141
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3142<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3143<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144 immediately halt. The dynamic call stack is then searched for the
3145 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3146 Once found, execution continues at the "exceptional" destination block
3147 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3148 instruction in the dynamic call chain, undefined behavior results.</p>
3149
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3150<p>Note that the code generator does not yet completely support unwind, and
3151that the invoke/unwind semantics are likely to change in future versions.</p>
3152
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3153</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154
3155<!-- _______________________________________________________________________ -->
3156
3157<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3158Instruction</a> </div>
3159
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163<pre>
3164 unreachable
3165</pre>
3166
3167<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3168<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169 instruction is used to inform the optimizer that a particular portion of the
3170 code is not reachable. This can be used to indicate that the code after a
3171 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3172
3173<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3174<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3175
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3176</div>
3177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3178<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3179<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3180
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3181<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182
3183<p>Binary operators are used to do most of the computation in a program. They
3184 require two operands of the same type, execute an operation on them, and
3185 produce a single value. The operands might represent multiple data, as is
3186 the case with the <a href="#t_vector">vector</a> data type. The result value
3187 has the same type as its operands.</p>
3188
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3189<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3190
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3191</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3193<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3194<div class="doc_subsubsection">
3195 <a name="i_add">'<tt>add</tt>' Instruction</a>
3196</div>
3197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3198<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3202 &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]3203 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3204 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3205 &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]3206</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3208<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3209<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3212<p>The two arguments to the '<tt>add</tt>' instruction must
3213 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3214 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3216<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3217<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3218
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219<p>If the sum has unsigned overflow, the result returned is the mathematical
3220 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]3221
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222<p>Because LLVM integers use a two's complement representation, this instruction
3223 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3224
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3225<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3226 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3227 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3228 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3229 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3230
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3231<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3232<pre>
3233 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3234</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3236</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3238<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3240 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3241</div>
3242
3243<div class="doc_text">
3244
3245<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3246<pre>
3247 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3248</pre>
3249
3250<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3251<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3252
3253<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3254<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3255 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3256 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3257
3258<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3259<p>The value produced is the floating point sum of the two operands.</p>
3260
3261<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3262<pre>
3263 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3264</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3266</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3268<!-- _______________________________________________________________________ -->
3269<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3270 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3271</div>
3272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3273<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3275<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3276<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3277 &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]3278 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3279 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3280 &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]3281</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3283<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3284<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3286
3287<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3288 '<tt>neg</tt>' instruction present in most other intermediate
3289 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3292<p>The two arguments to the '<tt>sub</tt>' instruction must
3293 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3294 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3297<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3299<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3300 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3301 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3302
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3303<p>Because LLVM integers use a two's complement representation, this instruction
3304 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3306<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3307 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3308 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3309 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3310 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3312<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3313<pre>
3314 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3315 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3316</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3318</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3320<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3321<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3322 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3323</div>
3324
3325<div class="doc_text">
3326
3327<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3328<pre>
3329 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3330</pre>
3331
3332<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3333<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3334 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3335
3336<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3337 '<tt>fneg</tt>' instruction present in most other intermediate
3338 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3339
3340<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3341<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3343 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3344
3345<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3346<p>The value produced is the floating point difference of the two operands.</p>
3347
3348<h5>Example:</h5>
3349<pre>
3350 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3351 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3352</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3353
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3354</div>
3355
3356<!-- _______________________________________________________________________ -->
3357<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3358 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3359</div>
3360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3361<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3363<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3365 &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]3366 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3367 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3368 &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]3369</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3371<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3372<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3375<p>The two arguments to the '<tt>mul</tt>' instruction must
3376 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3377 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3378
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3380<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3381
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3382<p>If the result of the multiplication has unsigned overflow, the result
3383 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3384 width of the result.</p>
3385
3386<p>Because LLVM integers use a two's complement representation, and the result
3387 is the same width as the operands, this instruction returns the correct
3388 result for both signed and unsigned integers. If a full product
3389 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3390 be sign-extended or zero-extended as appropriate to the width of the full
3391 product.</p>
3392
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3393<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3394 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3395 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3396 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3397 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3399<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3400<pre>
3401 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3402</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3404</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3405
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3406<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407<div class="doc_subsubsection">
3408 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3409</div>
3410
3411<div class="doc_text">
3412
3413<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
3415 &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]3416</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3418<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3419<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3420
3421<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3422<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3424 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3427<p>The value produced is the floating point product of the two operands.</p>
3428
3429<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &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]3432</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3434</div>
3435
3436<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3437<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3438</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3440<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3442<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3445</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3447<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3448<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3449
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3451<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3453 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3456<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3457
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3458<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3459 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3460
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3461<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3466</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3468</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3470<!-- _______________________________________________________________________ -->
3471<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3472</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3474<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3477<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3478 &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]3479 &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]3480</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3481
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3484
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3486<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3488 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3489
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The value produced is the signed integer quotient of the two operands rounded
3492 towards zero.</p>
3493
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3494<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3496
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3497<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498 undefined behavior; this is a rare case, but can occur, for example, by doing
3499 a 32-bit division of -2147483648 by -1.</p>
3500
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3501<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3502 <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]3503 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3504
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3508</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3509
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3510</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3512<!-- _______________________________________________________________________ -->
3513<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3514Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3516<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3518<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3519<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3520 &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]3521</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523<h5>Overview:</h5>
3524<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3525
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3526<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3527<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3529 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3530
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3531<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3532<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3533
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3534<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3535<pre>
3536 &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]3537</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3540
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3541<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3542<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3543</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3545<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3546
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3547<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548<pre>
3549 &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]3550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3552<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3553<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3554 division of its two arguments.</p>
3555
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3556<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3557<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3558 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3559 values. Both arguments must have identical types.</p>
3560
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3561<h5>Semantics:</h5>
3562<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3563 This instruction always performs an unsigned division to get the
3564 remainder.</p>
3565
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3566<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3568
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3569<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3571<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3572<pre>
3573 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3574</pre>
3575
3576</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3578<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3579<div class="doc_subsubsection">
3580 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3581</div>
3582
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3584
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3585<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3586<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3587 &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]3588</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3590<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3592 division of its two operands. This instruction can also take
3593 <a href="#t_vector">vector</a> versions of the values in which case the
3594 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3595
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3596<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3597<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3599 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3600
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3602<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3604 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3605 a value. For more information about the difference,
3606 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3607 Math Forum</a>. For a table of how this is implemented in various languages,
3608 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3609 Wikipedia: modulo operation</a>.</p>
3610
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3611<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3613
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3614<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615 Overflow also leads to undefined behavior; this is a rare case, but can
3616 occur, for example, by taking the remainder of a 32-bit division of
3617 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3618 lets srem be implemented using instructions that return both the result of
3619 the division and the remainder.)</p>
3620
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3621<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3624</pre>
3625
3626</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3629<div class="doc_subsubsection">
3630 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3631
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3632<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3633
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3634<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &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]3637</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3638
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3639<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3641 its two operands.</p>
3642
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3643<h5>Arguments:</h5>
3644<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3645 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3646 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3647
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3648<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649<p>This instruction returns the <i>remainder</i> of a division. The remainder
3650 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3651
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3653<pre>
3654 &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]3655</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3657</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3658
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3659<!-- ======================================================================= -->
3660<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3661Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3663<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3664
3665<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3666 program. They are generally very efficient instructions and can commonly be
3667 strength reduced from other instructions. They require two operands of the
3668 same type, execute an operation on them, and produce a single value. The
3669 resulting value is the same type as its operands.</p>
3670
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3671</div>
3672
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3673<!-- _______________________________________________________________________ -->
3674<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3675Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3676
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3677<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3679<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3680<pre>
3681 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3682</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3683
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3684<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3685<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3686 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3687
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3688<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3690 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3691 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3692
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3693<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3695 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3696 is (statically or dynamically) negative or equal to or larger than the number
3697 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3698 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3699 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3700
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701<h5>Example:</h5>
3702<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3703 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3704 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3705 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3706 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3707 &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]3708</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3710</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3714Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3717
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3718<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3719<pre>
3720 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3721</pre>
3722
3723<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3725 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3726
3727<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3728<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3729 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3730 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3731
3732<h5>Semantics:</h5>
3733<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3734 significant bits of the result will be filled with zero bits after the shift.
3735 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3736 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3737 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3738 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Example:</h5>
3741<pre>
3742 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3743 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3744 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3745 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3746 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3747 &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]3748</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3750</div>
3751
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3752<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3754Instruction</a> </div>
3755<div class="doc_text">
3756
3757<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3760</pre>
3761
3762<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3763<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3764 operand shifted to the right a specified number of bits with sign
3765 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3766
3767<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3768<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3770 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773<p>This instruction always performs an arithmetic shift right operation, The
3774 most significant bits of the result will be filled with the sign bit
3775 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3776 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3777 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3778 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Example:</h5>
3781<pre>
3782 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3783 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3784 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3785 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3786 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3787 &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]3788</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3790</div>
3791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3792<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3793<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3794Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3796<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3799<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3800 &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]3801</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3803<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3804<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3805 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3806
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3807<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3808<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3809 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3810 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3812<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3813<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3815<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3816 <tbody>
3817 <tr>
3818 <td>In0</td>
3819 <td>In1</td>
3820 <td>Out</td>
3821 </tr>
3822 <tr>
3823 <td>0</td>
3824 <td>0</td>
3825 <td>0</td>
3826 </tr>
3827 <tr>
3828 <td>0</td>
3829 <td>1</td>
3830 <td>0</td>
3831 </tr>
3832 <tr>
3833 <td>1</td>
3834 <td>0</td>
3835 <td>0</td>
3836 </tr>
3837 <tr>
3838 <td>1</td>
3839 <td>1</td>
3840 <td>1</td>
3841 </tr>
3842 </tbody>
3843</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3845<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3846<pre>
3847 &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]3848 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3849 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3850</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3851</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3852<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3853<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3854
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855<div class="doc_text">
3856
3857<h5>Syntax:</h5>
3858<pre>
3859 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3860</pre>
3861
3862<h5>Overview:</h5>
3863<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3864 two operands.</p>
3865
3866<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3867<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3869 values. Both arguments must have identical types.</p>
3870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3871<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3872<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3873
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3874<table border="1" cellspacing="0" cellpadding="4">
3875 <tbody>
3876 <tr>
3877 <td>In0</td>
3878 <td>In1</td>
3879 <td>Out</td>
3880 </tr>
3881 <tr>
3882 <td>0</td>
3883 <td>0</td>
3884 <td>0</td>
3885 </tr>
3886 <tr>
3887 <td>0</td>
3888 <td>1</td>
3889 <td>1</td>
3890 </tr>
3891 <tr>
3892 <td>1</td>
3893 <td>0</td>
3894 <td>1</td>
3895 </tr>
3896 <tr>
3897 <td>1</td>
3898 <td>1</td>
3899 <td>1</td>
3900 </tr>
3901 </tbody>
3902</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<pre>
3906 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3907 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3908 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3911</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3913<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3914<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3915Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3917<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3919<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920<pre>
3921 &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]3922</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3924<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3925<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3926 its two operands. The <tt>xor</tt> is used to implement the "one's
3927 complement" operation, which is the "~" operator in C.</p>
3928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3930<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3932 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3934<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3935<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3937<table border="1" cellspacing="0" cellpadding="4">
3938 <tbody>
3939 <tr>
3940 <td>In0</td>
3941 <td>In1</td>
3942 <td>Out</td>
3943 </tr>
3944 <tr>
3945 <td>0</td>
3946 <td>0</td>
3947 <td>0</td>
3948 </tr>
3949 <tr>
3950 <td>0</td>
3951 <td>1</td>
3952 <td>1</td>
3953 </tr>
3954 <tr>
3955 <td>1</td>
3956 <td>0</td>
3957 <td>1</td>
3958 </tr>
3959 <tr>
3960 <td>1</td>
3961 <td>1</td>
3962 <td>0</td>
3963 </tr>
3964 </tbody>
3965</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3966
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3967<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968<pre>
3969 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3970 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3971 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3972 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3975</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3977<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3978<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3979 <a name="vectorops">Vector Operations</a>
3980</div>
3981
3982<div class="doc_text">
3983
3984<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3985 target-independent manner. These instructions cover the element-access and
3986 vector-specific operations needed to process vectors effectively. While LLVM
3987 does directly support these vector operations, many sophisticated algorithms
3988 will want to use target-specific intrinsics to take full advantage of a
3989 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3990
3991</div>
3992
3993<!-- _______________________________________________________________________ -->
3994<div class="doc_subsubsection">
3995 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3996</div>
3997
3998<div class="doc_text">
3999
4000<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4001<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4002 &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]4003</pre>
4004
4005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4007 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4008
4009
4010<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4012 of <a href="#t_vector">vector</a> type. The second operand is an index
4013 indicating the position from which to extract the element. The index may be
4014 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4015
4016<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4017<p>The result is a scalar of the same type as the element type of
4018 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4019 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4020 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4021
4022<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4023<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4024 &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]4025</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<!-- _______________________________________________________________________ -->
4030<div class="doc_subsubsection">
4031 <a name="i_insertelement">'<tt>insertelement</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>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4038 &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]4039</pre>
4040
4041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4043 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4044
4045<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4047 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4048 whose type must equal the element type of the first operand. The third
4049 operand is an index indicating the position at which to insert the value.
4050 The index may be 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 vector of the same type as <tt>val</tt>. Its element values
4054 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4055 value <tt>elt</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; = 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]4061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4063</div>
4064
4065<!-- _______________________________________________________________________ -->
4066<div class="doc_subsubsection">
4067 <a name="i_shufflevector">'<tt>shufflevector</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>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4074 &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]4075</pre>
4076
4077<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4079 from two input vectors, returning a vector with the same element type as the
4080 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4081
4082<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4083<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4084 with types that match each other. The third argument is a shuffle mask whose
4085 element type is always 'i32'. The result of the instruction is a vector
4086 whose length is the same as the shuffle mask and whose element type is the
4087 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4089<p>The shuffle mask operand is required to be a constant vector with either
4090 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4091
4092<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093<p>The elements of the two input vectors are numbered from left to right across
4094 both of the vectors. The shuffle mask operand specifies, for each element of
4095 the result vector, which element of the two input vectors the result element
4096 gets. The element selector may be undef (meaning "don't care") and the
4097 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4098
4099<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4100<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4101 &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]4102 &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]4103 &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]4104 &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]4105 &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]4106 &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]4107 &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]4108 &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]4109</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4111</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4112
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4114<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4115 <a name="aggregateops">Aggregate Operations</a>
4116</div>
4117
4118<div class="doc_text">
4119
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4120<p>LLVM supports several instructions for working with
4121 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4122
4123</div>
4124
4125<!-- _______________________________________________________________________ -->
4126<div class="doc_subsubsection">
4127 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4128</div>
4129
4130<div class="doc_text">
4131
4132<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4133<pre>
4134 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4135</pre>
4136
4137<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4138<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4139 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4140
4141<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4143 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4144 <a href="#t_array">array</a> type. The operands are constant indices to
4145 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4146 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4147 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4148 <ul>
4149 <li>Since the value being indexed is not a pointer, the first index is
4150 omitted and assumed to be zero.</li>
4151 <li>At least one index must be specified.</li>
4152 <li>Not only struct indices but also array indices must be in
4153 bounds.</li>
4154 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4155
4156<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4157<p>The result is the value at the position in the aggregate specified by the
4158 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4159
4160<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4162 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4163</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4166
4167<!-- _______________________________________________________________________ -->
4168<div class="doc_subsubsection">
4169 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4170</div>
4171
4172<div class="doc_text">
4173
4174<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4175<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4176 &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]4177</pre>
4178
4179<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4180<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4181 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4182
4183<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4184<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4185 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4186 <a href="#t_array">array</a> type. The second operand is a first-class
4187 value to insert. The following operands are constant indices indicating
4188 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]4189 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4190 value to insert must have the same type as the value identified by the
4191 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4192
4193<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4195 that of <tt>val</tt> except that the value at the position specified by the
4196 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4199<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4200 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4201 %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]4202</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4203
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4204</div>
4205
4206
4207<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4208<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4209 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4210</div>
4211
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4212<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4213
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214<p>A key design point of an SSA-based representation is how it represents
4215 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4216 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4217 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4219</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4222<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4224</div>
4225
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4226<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4227
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4228<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4229<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4230 &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]4231</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4234<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235 currently executing function, to be automatically released when this function
4236 returns to its caller. The object is always allocated in the generic address
4237 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240<p>The '<tt>alloca</tt>' instruction
4241 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4242 runtime stack, returning a pointer of the appropriate type to the program.
4243 If "NumElements" is specified, it is the number of elements allocated,
4244 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4245 specified, the value result of the allocation is guaranteed to be aligned to
4246 at least that boundary. If not specified, or if zero, the target can choose
4247 to align the allocation on any convenient boundary compatible with the
4248 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4249
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4250<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4252<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4253<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4255 memory is automatically released when the function returns. The
4256 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4257 variables that must have an address available. When the function returns
4258 (either with the <tt><a href="#i_ret">ret</a></tt>
4259 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4260 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4261
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4262<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4263<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4264 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4265 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4266 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4267 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4268</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4270</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4271
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4272<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4273<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4274Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4275
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4276<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4277
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4278<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4279<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4280 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4281 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4282 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4283</pre>
4284
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4285<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4286<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4287
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4288<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4289<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4290 from which to load. The pointer must point to
4291 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4292 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4293 number or order of execution of this <tt>load</tt> with other <a
4294 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4296<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297 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]4298 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4299 alignment for the target. It is the responsibility of the code emitter to
4300 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4301 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302 produce less efficient code. An alignment of 1 is always safe.</p>
4303
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4304<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4305 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4306 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4307 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4308 and code generator that this load is not expected to be reused in the cache.
4309 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4310 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4311
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4312<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The location of memory pointed to is loaded. If the value being loaded is of
4314 scalar type then the number of bytes read does not exceed the minimum number
4315 of bytes needed to hold all bits of the type. For example, loading an
4316 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4317 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4318 is undefined if the value was not originally written using a store of the
4319 same type.</p>
4320
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4321<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4322<pre>
4323 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4324 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4325 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4326</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4328</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4330<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4331<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4332Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4334<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4336<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4337<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4338 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>
4339 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]4340</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4342<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4343<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4345<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4347 and an address at which to store it. The type of the
4348 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4349 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4350 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4351 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4352 order of execution of this <tt>store</tt> with other <a
4353 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4354
4355<p>The optional constant "align" argument specifies the alignment of the
4356 operation (that is, the alignment of the memory address). A value of 0 or an
4357 omitted "align" argument means that the operation has the preferential
4358 alignment for the target. It is the responsibility of the code emitter to
4359 ensure that the alignment information is correct. Overestimating the
4360 alignment results in an undefined behavior. Underestimating the alignment may
4361 produce less efficient code. An alignment of 1 is always safe.</p>
4362
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4363<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4364 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4365 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4366 instruction tells the optimizer and code generator that this load is
4367 not expected to be reused in the cache. The code generator may
4368 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4369 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4370
4371
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4372<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4373<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4374 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4375 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4376 does not exceed the minimum number of bytes needed to hold all bits of the
4377 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4378 writing a value of a type like <tt>i20</tt> with a size that is not an
4379 integral number of bytes, it is unspecified what happens to the extra bits
4380 that do not belong to the type, but they will typically be overwritten.</p>
4381
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4382<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383<pre>
4384 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4385 store i32 3, i32* %ptr <i>; yields {void}</i>
4386 %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]4387</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4389</div>
4390
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4391<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4392<div class="doc_subsubsection">
4393 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4394</div>
4395
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4396<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4398<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4399<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4400 &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]4401 &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]4402</pre>
4403
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4404<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4406 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4407 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4408
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4410<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4411 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4412 elements of the aggregate object are indexed. The interpretation of each
4413 index is dependent on the type being indexed into. The first index always
4414 indexes the pointer value given as the first argument, the second index
4415 indexes a value of the type pointed to (not necessarily the value directly
4416 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4417 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4418 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4419 can never be pointers, since that would require loading the pointer before
4420 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4421
4422<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]4423 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4424 integer <b>constants</b> are allowed. When indexing into an array, pointer
4425 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]4426 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4427
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4428<p>For example, let's consider a C code fragment and how it gets compiled to
4429 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4430
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4431<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4432struct RT {
4433 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4434 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4435 char C;
4436};
4437struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4438 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4439 double Y;
4440 struct RT Z;
4441};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4442
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4443int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4444 return &amp;s[1].Z.B[5][13];
4445}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4446</pre>
4447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4448<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4450<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4451%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4452%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4453
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4454define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4455entry:
4456 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4457 ret i32* %reg
4458}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4459</pre>
4460
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4461<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4462<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]4463 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4464 }</tt>' type, a structure. The second index indexes into the third element
4465 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4466 i8 }</tt>' type, another structure. The third index indexes into the second
4467 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4468 array. The two dimensions of the array are subscripted into, yielding an
4469 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4470 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4471
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4472<p>Note that it is perfectly legal to index partially through a structure,
4473 returning a pointer to an inner element. Because of this, the LLVM code for
4474 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4475
4476<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4477 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4478 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4479 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4480 %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]4481 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4482 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4483 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4484 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4485</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4486
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4487<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4488 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4489 base pointer is not an <i>in bounds</i> address of an allocated object,
4490 or if any of the addresses that would be formed by successive addition of
4491 the offsets implied by the indices to the base address with infinitely
4492 precise arithmetic are not an <i>in bounds</i> address of that allocated
4493 object. The <i>in bounds</i> addresses for an allocated object are all
4494 the addresses that point into the object, plus the address one byte past
4495 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4496
4497<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4498 the base address with silently-wrapping two's complement arithmetic, and
4499 the result value of the <tt>getelementptr</tt> may be outside the object
4500 pointed to by the base pointer. The result value may not necessarily be
4501 used to access memory though, even if it happens to point into allocated
4502 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4503 section for more information.</p>
4504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4505<p>The getelementptr instruction is often confusing. For some more insight into
4506 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4507
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4508<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4509<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4510 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4511 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4512 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4513 %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]4514 <i>; yields i8*:eptr</i>
4515 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4516 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4517 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4518</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4519
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4520</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4521
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4522<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4523<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4524</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4526<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4527
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4528<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529 which all take a single operand and a type. They perform various bit
4530 conversions on the operand.</p>
4531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4532</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4533
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4534<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4535<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4536 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4537</div>
4538<div class="doc_text">
4539
4540<h5>Syntax:</h5>
4541<pre>
4542 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4543</pre>
4544
4545<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4546<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4547 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4548
4549<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4551 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4552 size and type of the result, which must be
4553 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4554 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4555 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4556
4557<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4558<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4559 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4560 source size must be larger than the destination size, <tt>trunc</tt> cannot
4561 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4562
4563<h5>Example:</h5>
4564<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4565 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4566 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4567 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4568</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4569
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4570</div>
4571
4572<!-- _______________________________________________________________________ -->
4573<div class="doc_subsubsection">
4574 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4575</div>
4576<div class="doc_text">
4577
4578<h5>Syntax:</h5>
4579<pre>
4580 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4581</pre>
4582
4583<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4584<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4586
4587
4588<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4589<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4590 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4591 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4592 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4593 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4594
4595<h5>Semantics:</h5>
4596<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]4597 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4598
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4599<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]4600
4601<h5>Example:</h5>
4602<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4603 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4604 %Y = zext i1 true to i32 <i>; yields i32:1</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_sext">'<tt>sext .. to</tt>' Instruction</a>
4612</div>
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
4616<pre>
4617 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4618</pre>
4619
4620<h5>Overview:</h5>
4621<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4622
4623<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4624<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4625 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4626 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4627 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4632 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4633 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4634
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4635<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]4636
4637<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4638<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4639 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4640 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4641</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4643</div>
4644
4645<!-- _______________________________________________________________________ -->
4646<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4647 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4648</div>
4649
4650<div class="doc_text">
4651
4652<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4653<pre>
4654 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4655</pre>
4656
4657<h5>Overview:</h5>
4658<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4660
4661<h5>Arguments:</h5>
4662<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4664 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]4665 <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]4666 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4667
4668<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4670 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671 <a href="#t_floating">floating point</a> type. If the value cannot fit
4672 within the destination type, <tt>ty2</tt>, then the results are
4673 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4674
4675<h5>Example:</h5>
4676<pre>
4677 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4678 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4679</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4681</div>
4682
4683<!-- _______________________________________________________________________ -->
4684<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4685 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4686</div>
4687<div class="doc_text">
4688
4689<h5>Syntax:</h5>
4690<pre>
4691 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4692</pre>
4693
4694<h5>Overview:</h5>
4695<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]4696 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4697
4698<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4699<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4700 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4701 a <a href="#t_floating">floating point</a> type to cast it to. The source
4702 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4703
4704<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4705<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> type to a larger
4707 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4708 used to make a <i>no-op cast</i> because it always changes bits. Use
4709 <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]4710
4711<h5>Example:</h5>
4712<pre>
4713 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4714 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4715</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4717</div>
4718
4719<!-- _______________________________________________________________________ -->
4720<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4721 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4722</div>
4723<div class="doc_text">
4724
4725<h5>Syntax:</h5>
4726<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4727 &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]4728</pre>
4729
4730<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4731<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4733
4734<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4735<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4736 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4737 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4738 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4739 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4740
4741<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4742<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4744 towards zero) unsigned integer value. If the value cannot fit
4745 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4746
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4747<h5>Example:</h5>
4748<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4749 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4750 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4751 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4752</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4754</div>
4755
4756<!-- _______________________________________________________________________ -->
4757<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4758 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4759</div>
4760<div class="doc_text">
4761
4762<h5>Syntax:</h5>
4763<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4764 &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]4765</pre>
4766
4767<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4768<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4769 <a href="#t_floating">floating point</a> <tt>value</tt> to
4770 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4771
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4772<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4774 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4775 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4776 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4777 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4778
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4779<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4780<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4782 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4783 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4784
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4785<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4786<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4787 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4788 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4789 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4790</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4791
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4792</div>
4793
4794<!-- _______________________________________________________________________ -->
4795<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4796 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4797</div>
4798<div class="doc_text">
4799
4800<h5>Syntax:</h5>
4801<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4802 &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]4803</pre>
4804
4805<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4806<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4807 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4808
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4809<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4810<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]4811 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4812 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4813 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4814 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4815
4816<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4817<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4818 integer quantity and converts it to the corresponding floating point
4819 value. If the value cannot fit in the floating point value, the results are
4820 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4821
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4822<h5>Example:</h5>
4823<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4824 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4825 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4826</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4827
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4828</div>
4829
4830<!-- _______________________________________________________________________ -->
4831<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4832 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4833</div>
4834<div class="doc_text">
4835
4836<h5>Syntax:</h5>
4837<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4838 &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]4839</pre>
4840
4841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4843 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4844
4845<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4846<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]4847 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4848 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4849 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4850 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4851
4852<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4854 quantity and converts it to the corresponding floating point value. If the
4855 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4856
4857<h5>Example:</h5>
4858<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4859 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4860 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4861</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4867 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4868</div>
4869<div class="doc_text">
4870
4871<h5>Syntax:</h5>
4872<pre>
4873 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4874</pre>
4875
4876<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4877<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4878 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4879
4880<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4881<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4882 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4883 <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]4884
4885<h5>Semantics:</h5>
4886<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4888 truncating or zero extending that value to the size of the integer type. If
4889 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4890 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4891 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4892 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4893
4894<h5>Example:</h5>
4895<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4896 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4897 %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]4898</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4900</div>
4901
4902<!-- _______________________________________________________________________ -->
4903<div class="doc_subsubsection">
4904 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4905</div>
4906<div class="doc_text">
4907
4908<h5>Syntax:</h5>
4909<pre>
4910 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4911</pre>
4912
4913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4914<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4915 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4916
4917<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4918<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4919 value to cast, and a type to cast it to, which must be a
4920 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4921
4922<h5>Semantics:</h5>
4923<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4925 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4926 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4927 than the size of a pointer then a zero extension is done. If they are the
4928 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4929
4930<h5>Example:</h5>
4931<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4932 %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]4933 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4934 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4935</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4936
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4937</div>
4938
4939<!-- _______________________________________________________________________ -->
4940<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4941 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4942</div>
4943<div class="doc_text">
4944
4945<h5>Syntax:</h5>
4946<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4947 &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]4948</pre>
4949
4950<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4951<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4952 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4953
4954<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4956 non-aggregate first class value, and a type to cast it to, which must also be
4957 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4958 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4959 identical. If the source type is a pointer, the destination type must also be
4960 a pointer. This instruction supports bitwise conversion of vectors to
4961 integers and to vectors of other types (as long as they have the same
4962 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4963
4964<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4965<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4966 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4967 this conversion. The conversion is done as if the <tt>value</tt> had been
4968 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4969 be converted to other pointer types with this instruction. To convert
4970 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4971 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4972
4973<h5>Example:</h5>
4974<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4975 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4976 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4977 %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]4978</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4980</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4981
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4982<!-- ======================================================================= -->
4983<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4985<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4986
4987<p>The instructions in this category are the "miscellaneous" instructions, which
4988 defy better classification.</p>
4989
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4990</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4991
4992<!-- _______________________________________________________________________ -->
4993<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4994</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4996<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4998<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4999<pre>
5000 &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]5001</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5003<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5005 boolean values based on comparison of its two integer, integer vector, or
5006 pointer operands.</p>
5007
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5008<h5>Arguments:</h5>
5009<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5010 the condition code indicating the kind of comparison to perform. It is not a
5011 value, just a keyword. The possible condition code are:</p>
5012
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5013<ol>
5014 <li><tt>eq</tt>: equal</li>
5015 <li><tt>ne</tt>: not equal </li>
5016 <li><tt>ugt</tt>: unsigned greater than</li>
5017 <li><tt>uge</tt>: unsigned greater or equal</li>
5018 <li><tt>ult</tt>: unsigned less than</li>
5019 <li><tt>ule</tt>: unsigned less or equal</li>
5020 <li><tt>sgt</tt>: signed greater than</li>
5021 <li><tt>sge</tt>: signed greater or equal</li>
5022 <li><tt>slt</tt>: signed less than</li>
5023 <li><tt>sle</tt>: signed less or equal</li>
5024</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5026<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5028 typed. They must also be identical types.</p>
5029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5030<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5031<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5032 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5033 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]5034 result, as follows:</p>
5035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5036<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5037 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>false</tt> otherwise. No sign interpretation is necessary or
5039 performed.</li>
5040
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5041 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042 <tt>false</tt> otherwise. No sign interpretation is necessary or
5043 performed.</li>
5044
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5045 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5046 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5047
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5048 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5049 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5050 to <tt>op2</tt>.</li>
5051
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5052 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5053 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5054
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5055 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5057
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5058 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5060
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5063 to <tt>op2</tt>.</li>
5064
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5065 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5067
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5068 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5069 <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]5070</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5072<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073 values are compared as if they were integers.</p>
5074
5075<p>If the operands are integer vectors, then they are compared element by
5076 element. The result is an <tt>i1</tt> vector with the same number of elements
5077 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5078
5079<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<pre>
5081 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5082 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5083 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5084 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5085 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5086 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5087</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5088
5089<p>Note that the code generator does not yet support vector types with
5090 the <tt>icmp</tt> instruction.</p>
5091
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5092</div>
5093
5094<!-- _______________________________________________________________________ -->
5095<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5096</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5098<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5099
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5100<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101<pre>
5102 &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]5103</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5105<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5107 values based on comparison of its operands.</p>
5108
5109<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]5110(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5111
5112<p>If the operands are floating point vectors, then the result type is a vector
5113 of boolean with the same number of elements as the operands being
5114 compared.</p>
5115
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5116<h5>Arguments:</h5>
5117<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5118 the condition code indicating the kind of comparison to perform. It is not a
5119 value, just a keyword. The possible condition code are:</p>
5120
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5121<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5122 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5123 <li><tt>oeq</tt>: ordered and equal</li>
5124 <li><tt>ogt</tt>: ordered and greater than </li>
5125 <li><tt>oge</tt>: ordered and greater than or equal</li>
5126 <li><tt>olt</tt>: ordered and less than </li>
5127 <li><tt>ole</tt>: ordered and less than or equal</li>
5128 <li><tt>one</tt>: ordered and not equal</li>
5129 <li><tt>ord</tt>: ordered (no nans)</li>
5130 <li><tt>ueq</tt>: unordered or equal</li>
5131 <li><tt>ugt</tt>: unordered or greater than </li>
5132 <li><tt>uge</tt>: unordered or greater than or equal</li>
5133 <li><tt>ult</tt>: unordered or less than </li>
5134 <li><tt>ule</tt>: unordered or less than or equal</li>
5135 <li><tt>une</tt>: unordered or not equal</li>
5136 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5137 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5138</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5139
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5140<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5141 <i>unordered</i> means that either operand may be a QNAN.</p>
5142
5143<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5144 a <a href="#t_floating">floating point</a> type or
5145 a <a href="#t_vector">vector</a> of floating point type. They must have
5146 identical types.</p>
5147
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5148<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5149<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150 according to the condition code given as <tt>cond</tt>. If the operands are
5151 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5152 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5153 follows:</p>
5154
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5155<ol>
5156 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5157
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5160
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5161 <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]5162 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5164 <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]5165 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5166
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5169
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5170 <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]5171 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5172
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5175
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5176 <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]5177
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5180
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5181 <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]5182 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5183
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5184 <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]5185 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5186
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5189
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5192
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5195
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5196 <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]5197
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5198 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5199</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5200
5201<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202<pre>
5203 &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]5204 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5205 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5206 &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]5207</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5208
5209<p>Note that the code generator does not yet support vector types with
5210 the <tt>fcmp</tt> instruction.</p>
5211
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5212</div>
5213
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5214<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5215<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5216 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5217</div>
5218
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5219<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5220
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5221<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5222<pre>
5223 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5224</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5225
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5227<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5228 SSA graph representing the function.</p>
5229
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5230<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5231<p>The type of the incoming values is specified with the first type field. After
5232 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5233 one pair for each predecessor basic block of the current block. Only values
5234 of <a href="#t_firstclass">first class</a> type may be used as the value
5235 arguments to the PHI node. Only labels may be used as the label
5236 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5237
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5238<p>There must be no non-phi instructions between the start of a basic block and
5239 the PHI instructions: i.e. PHI instructions must be first in a basic
5240 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5241
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5242<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5243 occur on the edge from the corresponding predecessor block to the current
5244 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5245 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5246
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5247<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5248<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5249 specified by the pair corresponding to the predecessor basic block that
5250 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5251
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5252<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5253<pre>
5254Loop: ; Infinite loop that counts from 0 on up...
5255 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5256 %nextindvar = add i32 %indvar, 1
5257 br label %Loop
5258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5259
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5260</div>
5261
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="i_select">'<tt>select</tt>' Instruction</a>
5265</div>
5266
5267<div class="doc_text">
5268
5269<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5270<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5271 &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>
5272
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5273 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5274</pre>
5275
5276<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5278 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5279
5280
5281<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5282<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5283 values indicating the condition, and two values of the
5284 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5285 vectors and the condition is a scalar, then entire vectors are selected, not
5286 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5287
5288<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5289<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5290 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5291
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5292<p>If the condition is a vector of i1, then the value arguments must be vectors
5293 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5294
5295<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5296<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5297 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5298</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5299
5300<p>Note that the code generator does not yet support conditions
5301 with vector type.</p>
5302
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5303</div>
5304
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5305<!-- _______________________________________________________________________ -->
5306<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5307 <a name="i_call">'<tt>call</tt>' Instruction</a>
5308</div>
5309
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5310<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5312<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5313<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5314 &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]5315</pre>
5316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5317<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5318<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5320<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5321<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5322
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5323<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5324 <li>The optional "tail" marker indicates that the callee function does not
5325 access any allocas or varargs in the caller. Note that calls may be
5326 marked "tail" even if they do not occur before
5327 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5328 present, the function call is eligible for tail call optimization,
5329 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5330 optimized into a jump</a>. The code generator may optimize calls marked
5331 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5332 sibling call optimization</a> when the caller and callee have
5333 matching signatures, or 2) forced tail call optimization when the
5334 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5335 <ul>
5336 <li>Caller and callee both have the calling
5337 convention <tt>fastcc</tt>.</li>
5338 <li>The call is in tail position (ret immediately follows call and ret
5339 uses value of call or is void).</li>
5340 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5341 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5342 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5343 constraints are met.</a></li>
5344 </ul>
5345 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5346
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5347 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5348 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5349 defaults to using C calling conventions. The calling convention of the
5350 call must match the calling convention of the target function, or else the
5351 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5352
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5353 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5354 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5355 '<tt>inreg</tt>' attributes are valid here.</li>
5356
5357 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5358 type of the return value. Functions that return no value are marked
5359 <tt><a href="#t_void">void</a></tt>.</li>
5360
5361 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5362 being invoked. The argument types must match the types implied by this
5363 signature. This type can be omitted if the function is not varargs and if
5364 the function type does not return a pointer to a function.</li>
5365
5366 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5367 be invoked. In most cases, this is a direct function invocation, but
5368 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5369 to function value.</li>
5370
5371 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5372 signature argument types and parameter attributes. All arguments must be
5373 of <a href="#t_firstclass">first class</a> type. If the function
5374 signature indicates the function accepts a variable number of arguments,
5375 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5376
5377 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5378 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5379 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5380</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5381
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5382<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5383<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5384 a specified function, with its incoming arguments bound to the specified
5385 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5386 function, control flow continues with the instruction after the function
5387 call, and the return value of the function is bound to the result
5388 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5390<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5391<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5392 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5393 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5394 %X = tail call i32 @foo() <i>; yields i32</i>
5395 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5396 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5397
5398 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5399 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5400 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5401 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5402 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5403 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5404</pre>
5405
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5406<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5407standard C99 library as being the C99 library functions, and may perform
5408optimizations or generate code for them under that assumption. This is
5409something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5410freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5412</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5413
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5414<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5415<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5416 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5417</div>
5418
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5419<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5420
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5421<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5422<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5423 &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]5424</pre>
5425
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5427<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5428 the "variable argument" area of a function call. It is used to implement the
5429 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5430
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5431<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5432<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5433 argument. It returns a value of the specified argument type and increments
5434 the <tt>va_list</tt> to point to the next argument. The actual type
5435 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5436
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5437<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5438<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5439 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5440 to the next argument. For more information, see the variable argument
5441 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5442
5443<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]5444 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5445 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5447<p><tt>va_arg</tt> is an LLVM instruction instead of
5448 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5449 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5450
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5451<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5452<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5453
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5454<p>Note that the code generator does not yet fully support va_arg on many
5455 targets. Also, it does not currently support va_arg with aggregate types on
5456 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5457
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5458</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5459
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5460<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5461<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5462<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5464<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5465
5466<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5467 well known names and semantics and are required to follow certain
5468 restrictions. Overall, these intrinsics represent an extension mechanism for
5469 the LLVM language that does not require changing all of the transformations
5470 in LLVM when adding to the language (or the bitcode reader/writer, the
5471 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5472
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5473<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5475 begin with this prefix. Intrinsic functions must always be external
5476 functions: you cannot define the body of intrinsic functions. Intrinsic
5477 functions may only be used in call or invoke instructions: it is illegal to
5478 take the address of an intrinsic function. Additionally, because intrinsic
5479 functions are part of the LLVM language, it is required if any are added that
5480 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5481
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5482<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5483 family of functions that perform the same operation but on different data
5484 types. Because LLVM can represent over 8 million different integer types,
5485 overloading is used commonly to allow an intrinsic function to operate on any
5486 integer type. One or more of the argument types or the result type can be
5487 overloaded to accept any integer type. Argument types may also be defined as
5488 exactly matching a previous argument's type or the result type. This allows
5489 an intrinsic function which accepts multiple arguments, but needs all of them
5490 to be of the same type, to only be overloaded with respect to a single
5491 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5492
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493<p>Overloaded intrinsics will have the names of its overloaded argument types
5494 encoded into its function name, each preceded by a period. Only those types
5495 which are overloaded result in a name suffix. Arguments whose type is matched
5496 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5497 can take an integer of any width and returns an integer of exactly the same
5498 integer width. This leads to a family of functions such as
5499 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5500 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5501 suffix is required. Because the argument's type is matched against the return
5502 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5503
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5504<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5505 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5506
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5507</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5508
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5509<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5510<div class="doc_subsection">
5511 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5512</div>
5513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5514<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5516<p>Variable argument support is defined in LLVM with
5517 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5518 intrinsic functions. These functions are related to the similarly named
5519 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5521<p>All of these functions operate on arguments that use a target-specific value
5522 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5523 not define what this type is, so all transformations should be prepared to
5524 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5525
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5526<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]5527 instruction and the variable argument handling intrinsic functions are
5528 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5529
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5530<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5531define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5532 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5533 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5534 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5535 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5536
5537 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5538 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5539
5540 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5541 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5542 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5543 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5544 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5545
5546 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5547 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5548 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5549}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5550
5551declare void @llvm.va_start(i8*)
5552declare void @llvm.va_copy(i8*, i8*)
5553declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5554</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5555
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5556</div>
5557
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5558<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5559<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5560 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5561</div>
5562
5563
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5564<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5565
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5566<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<pre>
5568 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5569</pre>
5570
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5571<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5573 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]5574
5575<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5576<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]5577
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5578<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5579<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]5580 macro available in C. In a target-dependent way, it initializes
5581 the <tt>va_list</tt> element to which the argument points, so that the next
5582 call to <tt>va_arg</tt> will produce the first variable argument passed to
5583 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5584 need to know the last argument of the function as the compiler can figure
5585 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5587</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5588
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5589<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5590<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5591 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5592</div>
5593
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5594<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5595
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5596<h5>Syntax:</h5>
5597<pre>
5598 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5599</pre>
5600
5601<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5602<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5603 which has been initialized previously
5604 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5605 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5608<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]5609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5611<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]5612 macro available in C. In a target-dependent way, it destroys
5613 the <tt>va_list</tt> element to which the argument points. Calls
5614 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5615 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5616 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5617
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5618</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5619
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5620<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5621<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5622 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5623</div>
5624
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5625<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5626
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5628<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5629 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5630</pre>
5631
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5632<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5633<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5635
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5636<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5637<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]5638 The second argument is a pointer to a <tt>va_list</tt> element to copy
5639 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5640
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5641<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5642<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]5643 macro available in C. In a target-dependent way, it copies the
5644 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5645 element. This intrinsic is necessary because
5646 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5647 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5649</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5650
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5651<!-- ======================================================================= -->
5652<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5653 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5654</div>
5655
5656<div class="doc_text">
5657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5658<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5659Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5660intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5661roots on the stack</a>, as well as garbage collector implementations that
5662require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5663barriers. Front-ends for type-safe garbage collected languages should generate
5664these intrinsics to make use of the LLVM garbage collectors. For more details,
5665see <a href="GarbageCollection.html">Accurate Garbage Collection with
5666LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5667
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5668<p>The garbage collection intrinsics only operate on objects in the generic
5669 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5670
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5671</div>
5672
5673<!-- _______________________________________________________________________ -->
5674<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5675 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676</div>
5677
5678<div class="doc_text">
5679
5680<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5681<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5682 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683</pre>
5684
5685<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5686<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]5687 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688
5689<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5690<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5691 root pointer. The second pointer (which must be either a constant or a
5692 global value address) contains the meta-data to be associated with the
5693 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5694
5695<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5696<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]5697 location. At compile-time, the code generator generates information to allow
5698 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5699 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5700 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701
5702</div>
5703
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5704<!-- _______________________________________________________________________ -->
5705<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5706 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707</div>
5708
5709<div class="doc_text">
5710
5711<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5712<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5713 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5714</pre>
5715
5716<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5717<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5718 locations, allowing garbage collector implementations that require read
5719 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5720
5721<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5722<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]5723 allocated from the garbage collector. The first object is a pointer to the
5724 start of the referenced object, if needed by the language runtime (otherwise
5725 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5726
5727<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5728<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729 instruction, but may be replaced with substantially more complex code by the
5730 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5731 may only be used in a function which <a href="#gc">specifies a GC
5732 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5733
5734</div>
5735
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5736<!-- _______________________________________________________________________ -->
5737<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5738 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739</div>
5740
5741<div class="doc_text">
5742
5743<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5745 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5746</pre>
5747
5748<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5749<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5750 locations, allowing garbage collector implementations that require write
5751 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5752
5753<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5754<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]5755 object to store it to, and the third is the address of the field of Obj to
5756 store to. If the runtime does not require a pointer to the object, Obj may
5757 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5758
5759<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5760<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5761 instruction, but may be replaced with substantially more complex code by the
5762 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5763 may only be used in a function which <a href="#gc">specifies a GC
5764 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5765
5766</div>
5767
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5768<!-- ======================================================================= -->
5769<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5770 <a name="int_codegen">Code Generator Intrinsics</a>
5771</div>
5772
5773<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774
5775<p>These intrinsics are provided by LLVM to expose special features that may
5776 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5777
5778</div>
5779
5780<!-- _______________________________________________________________________ -->
5781<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5782 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5783</div>
5784
5785<div class="doc_text">
5786
5787<h5>Syntax:</h5>
5788<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5789 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5790</pre>
5791
5792<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5793<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5794 target-specific value indicating the return address of the current function
5795 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796
5797<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798<p>The argument to this intrinsic indicates which function to return the address
5799 for. Zero indicates the calling function, one indicates its caller, etc.
5800 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5801
5802<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5804 indicating the return address of the specified call frame, or zero if it
5805 cannot be identified. The value returned by this intrinsic is likely to be
5806 incorrect or 0 for arguments other than zero, so it should only be used for
5807 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5808
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809<p>Note that calling this intrinsic does not prevent function inlining or other
5810 aggressive transformations, so the value returned may not be that of the
5811 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5812
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813</div>
5814
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5815<!-- _______________________________________________________________________ -->
5816<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5817 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818</div>
5819
5820<div class="doc_text">
5821
5822<h5>Syntax:</h5>
5823<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5824 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5825</pre>
5826
5827<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5828<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5829 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5830
5831<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5832<p>The argument to this intrinsic indicates which function to return the frame
5833 pointer for. Zero indicates the calling function, one indicates its caller,
5834 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5835
5836<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5837<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5838 indicating the frame address of the specified call frame, or zero if it
5839 cannot be identified. The value returned by this intrinsic is likely to be
5840 incorrect or 0 for arguments other than zero, so it should only be used for
5841 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5843<p>Note that calling this intrinsic does not prevent function inlining or other
5844 aggressive transformations, so the value returned may not be that of the
5845 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5846
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5847</div>
5848
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5849<!-- _______________________________________________________________________ -->
5850<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5851 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5852</div>
5853
5854<div class="doc_text">
5855
5856<h5>Syntax:</h5>
5857<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5858 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5859</pre>
5860
5861<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5863 of the function stack, for use
5864 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5865 useful for implementing language features like scoped automatic variable
5866 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5867
5868<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869<p>This intrinsic returns a opaque pointer value that can be passed
5870 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5871 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5872 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5873 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5874 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5875 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5876
5877</div>
5878
5879<!-- _______________________________________________________________________ -->
5880<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5881 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5882</div>
5883
5884<div class="doc_text">
5885
5886<h5>Syntax:</h5>
5887<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5888 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5889</pre>
5890
5891<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5892<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5893 the function stack to the state it was in when the
5894 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5895 executed. This is useful for implementing language features like scoped
5896 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899<p>See the description
5900 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5901
5902</div>
5903
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5904<!-- _______________________________________________________________________ -->
5905<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5906 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5907</div>
5908
5909<div class="doc_text">
5910
5911<h5>Syntax:</h5>
5912<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5913 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]5914</pre>
5915
5916<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5918 insert a prefetch instruction if supported; otherwise, it is a noop.
5919 Prefetches have no effect on the behavior of the program but can change its
5920 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5924 specifier determining if the fetch should be for a read (0) or write (1),
5925 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5926 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5927 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5928
5929<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>This intrinsic does not modify the behavior of the program. In particular,
5931 prefetches cannot trap and do not produce a value. On targets that support
5932 this intrinsic, the prefetch can provide hints to the processor cache for
5933 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5934
5935</div>
5936
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5937<!-- _______________________________________________________________________ -->
5938<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5939 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5940</div>
5941
5942<div class="doc_text">
5943
5944<h5>Syntax:</h5>
5945<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5946 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5947</pre>
5948
5949<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5950<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5951 Counter (PC) in a region of code to simulators and other tools. The method
5952 is target specific, but it is expected that the marker will use exported
5953 symbols to transmit the PC of the marker. The marker makes no guarantees
5954 that it will remain with any specific instruction after optimizations. It is
5955 possible that the presence of a marker will inhibit optimizations. The
5956 intended use is to be inserted after optimizations to allow correlations of
5957 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5961
5962<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5963<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5964 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5965
5966</div>
5967
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5968<!-- _______________________________________________________________________ -->
5969<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5970 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5971</div>
5972
5973<div class="doc_text">
5974
5975<h5>Syntax:</h5>
5976<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5977 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5978</pre>
5979
5980<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5982 counter register (or similar low latency, high accuracy clocks) on those
5983 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5984 should map to RPCC. As the backing counters overflow quickly (on the order
5985 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5986
5987<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5988<p>When directly supported, reading the cycle counter should not modify any
5989 memory. Implementations are allowed to either return a application specific
5990 value or a system wide value. On backends without support, this is lowered
5991 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5992
5993</div>
5994
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5995<!-- ======================================================================= -->
5996<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5997 <a name="int_libc">Standard C Library Intrinsics</a>
5998</div>
5999
6000<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001
6002<p>LLVM provides intrinsics for a few important standard C library functions.
6003 These intrinsics allow source-language front-ends to pass information about
6004 the alignment of the pointer arguments to the code generator, providing
6005 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6006
6007</div>
6008
6009<!-- _______________________________________________________________________ -->
6010<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6011 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6012</div>
6013
6014<div class="doc_text">
6015
6016<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6017<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]6018 integer bit width and for different address spaces. Not all targets support
6019 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6020
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6021<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6022 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]6023 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6024 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]6025 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6026</pre>
6027
6028<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6030 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6031
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6032<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6033 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6034 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6035
6036<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6037
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038<p>The first argument is a pointer to the destination, the second is a pointer
6039 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6040 number of bytes to copy, the fourth argument is the alignment of the
6041 source and destination locations, and the fifth is a boolean indicating a
6042 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6043
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6044<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]6045 then the caller guarantees that both the source and destination pointers are
6046 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6047
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6048<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6049 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6050 The detailed access behavior is not very cleanly specified and it is unwise
6051 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6052
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6053<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6055<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6056 source location to the destination location, which are not allowed to
6057 overlap. It copies "len" bytes of memory over. If the argument is known to
6058 be aligned to some boundary, this can be specified as the fourth argument,
6059 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6060
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6061</div>
6062
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6063<!-- _______________________________________________________________________ -->
6064<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6065 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6066</div>
6067
6068<div class="doc_text">
6069
6070<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6071<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]6072 width and for different address space. Not all targets support all bit
6073 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6075<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6076 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]6077 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6078 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]6079 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6080</pre>
6081
6082<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6083<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6084 source location to the destination location. It is similar to the
6085 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6086 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6088<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6089 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6090 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6091
6092<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6093
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6094<p>The first argument is a pointer to the destination, the second is a pointer
6095 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6096 number of bytes to copy, the fourth argument is the alignment of the
6097 source and destination locations, and the fifth is a boolean indicating a
6098 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6099
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6100<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]6101 then the caller guarantees that the source and destination pointers are
6102 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6103
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6104<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6105 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6106 The detailed access behavior is not very cleanly specified and it is unwise
6107 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6108
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6109<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6112 source location to the destination location, which may overlap. It copies
6113 "len" bytes of memory over. If the argument is known to be aligned to some
6114 boundary, this can be specified as the fourth argument, otherwise it should
6115 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6116
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6117</div>
6118
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6119<!-- _______________________________________________________________________ -->
6120<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6121 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6122</div>
6123
6124<div class="doc_text">
6125
6126<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6127<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]6128 width and for different address spaces. However, not all targets support all
6129 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6130
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6131<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6132 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6133 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6134 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6135 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6136</pre>
6137
6138<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6139<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6140 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6141
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6142<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6143 intrinsic does not return a value and takes extra alignment/volatile
6144 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6145
6146<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6147<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]6148 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6150 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6151
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6152<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]6153 then the caller guarantees that the destination pointer is aligned to that
6154 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6155
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6156<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6157 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6158 The detailed access behavior is not very cleanly specified and it is unwise
6159 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6160
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6161<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6163 at the destination location. If the argument is known to be aligned to some
6164 boundary, this can be specified as the fourth argument, otherwise it should
6165 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6166
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6167</div>
6168
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6169<!-- _______________________________________________________________________ -->
6170<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6171 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6172</div>
6173
6174<div class="doc_text">
6175
6176<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6177<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6178 floating point or vector of floating point type. Not all targets support all
6179 types however.</p>
6180
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6181<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6182 declare float @llvm.sqrt.f32(float %Val)
6183 declare double @llvm.sqrt.f64(double %Val)
6184 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6185 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6186 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6187</pre>
6188
6189<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6190<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6191 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6192 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6193 behavior for negative numbers other than -0.0 (which allows for better
6194 optimization, because there is no need to worry about errno being
6195 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]6196
6197<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6198<p>The argument and return value are floating point numbers of the same
6199 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6200
6201<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6202<p>This function returns the sqrt of the specified operand if it is a
6203 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6204
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6205</div>
6206
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6207<!-- _______________________________________________________________________ -->
6208<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6209 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6210</div>
6211
6212<div class="doc_text">
6213
6214<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6215<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6216 floating point or vector of floating point type. Not all targets support all
6217 types however.</p>
6218
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6219<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6220 declare float @llvm.powi.f32(float %Val, i32 %power)
6221 declare double @llvm.powi.f64(double %Val, i32 %power)
6222 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6223 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6224 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6225</pre>
6226
6227<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6228<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6229 specified (positive or negative) power. The order of evaluation of
6230 multiplications is not defined. When a vector of floating point type is
6231 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6232
6233<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6234<p>The second argument is an integer power, and the first is a value to raise to
6235 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6236
6237<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238<p>This function returns the first value raised to the second power with an
6239 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6240
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6241</div>
6242
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6243<!-- _______________________________________________________________________ -->
6244<div class="doc_subsubsection">
6245 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6246</div>
6247
6248<div class="doc_text">
6249
6250<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6251<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6252 floating point or vector of floating point type. Not all targets support all
6253 types however.</p>
6254
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6255<pre>
6256 declare float @llvm.sin.f32(float %Val)
6257 declare double @llvm.sin.f64(double %Val)
6258 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6259 declare fp128 @llvm.sin.f128(fp128 %Val)
6260 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6261</pre>
6262
6263<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6264<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6265
6266<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6267<p>The argument and return value are floating point numbers of the same
6268 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6269
6270<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6271<p>This function returns the sine of the specified operand, returning the same
6272 values as the libm <tt>sin</tt> functions would, and handles error conditions
6273 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6274
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6275</div>
6276
6277<!-- _______________________________________________________________________ -->
6278<div class="doc_subsubsection">
6279 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6280</div>
6281
6282<div class="doc_text">
6283
6284<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6285<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6286 floating point or vector of floating point type. Not all targets support all
6287 types however.</p>
6288
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6289<pre>
6290 declare float @llvm.cos.f32(float %Val)
6291 declare double @llvm.cos.f64(double %Val)
6292 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6293 declare fp128 @llvm.cos.f128(fp128 %Val)
6294 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6295</pre>
6296
6297<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6298<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6299
6300<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301<p>The argument and return value are floating point numbers of the same
6302 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6303
6304<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6305<p>This function returns the cosine of the specified operand, returning the same
6306 values as the libm <tt>cos</tt> functions would, and handles error conditions
6307 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6308
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6309</div>
6310
6311<!-- _______________________________________________________________________ -->
6312<div class="doc_subsubsection">
6313 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6314</div>
6315
6316<div class="doc_text">
6317
6318<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6320 floating point or vector of floating point type. Not all targets support all
6321 types however.</p>
6322
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6323<pre>
6324 declare float @llvm.pow.f32(float %Val, float %Power)
6325 declare double @llvm.pow.f64(double %Val, double %Power)
6326 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6327 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6328 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6329</pre>
6330
6331<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6332<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6333 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6334
6335<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6336<p>The second argument is a floating point power, and the first is a value to
6337 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6338
6339<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6340<p>This function returns the first value raised to the second power, returning
6341 the same values as the libm <tt>pow</tt> functions would, and handles error
6342 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6343
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6344</div>
6345
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6346<!-- ======================================================================= -->
6347<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6348 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6349</div>
6350
6351<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6352
6353<p>LLVM provides intrinsics for a few important bit manipulation operations.
6354 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6355
6356</div>
6357
6358<!-- _______________________________________________________________________ -->
6359<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6360 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6361</div>
6362
6363<div class="doc_text">
6364
6365<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6366<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6367 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6368
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6369<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6370 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6371 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6372 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6373</pre>
6374
6375<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6376<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6377 values with an even number of bytes (positive multiple of 16 bits). These
6378 are useful for performing operations on data that is not in the target's
6379 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6380
6381<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6383 and low byte of the input i16 swapped. Similarly,
6384 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6385 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6386 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6387 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6388 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6389 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6390
6391</div>
6392
6393<!-- _______________________________________________________________________ -->
6394<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6395 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6396</div>
6397
6398<div class="doc_text">
6399
6400<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6401<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]6402 width. Not all targets support all bit widths however.</p>
6403
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6404<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6405 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6406 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6407 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6408 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6409 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6410</pre>
6411
6412<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6413<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6414 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6415
6416<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6417<p>The only argument is the value to be counted. The argument may be of any
6418 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6419
6420<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6421<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]6422
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6423</div>
6424
6425<!-- _______________________________________________________________________ -->
6426<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6427 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6428</div>
6429
6430<div class="doc_text">
6431
6432<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6433<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6434 integer bit width. Not all targets support all bit widths however.</p>
6435
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6436<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6437 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6438 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6439 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6440 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6441 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6442</pre>
6443
6444<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6445<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6446 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6447
6448<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6449<p>The only argument is the value to be counted. The argument may be of any
6450 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6451
6452<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6453<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6454 zeros in a variable. If the src == 0 then the result is the size in bits of
6455 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6456
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6457</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6458
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6459<!-- _______________________________________________________________________ -->
6460<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6461 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6462</div>
6463
6464<div class="doc_text">
6465
6466<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6467<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6468 integer bit width. Not all targets support all bit widths however.</p>
6469
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6470<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6471 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6472 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6473 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6474 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6475 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6476</pre>
6477
6478<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6479<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6480 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6481
6482<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6483<p>The only argument is the value to be counted. The argument may be of any
6484 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6485
6486<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6487<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6488 zeros in a variable. If the src == 0 then the result is the size in bits of
6489 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6490
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6491</div>
6492
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6493<!-- ======================================================================= -->
6494<div class="doc_subsection">
6495 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6496</div>
6497
6498<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6499
6500<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6501
6502</div>
6503
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6504<!-- _______________________________________________________________________ -->
6505<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6506 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6507</div>
6508
6509<div class="doc_text">
6510
6511<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6512<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]6513 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6514
6515<pre>
6516 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6517 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6518 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6519</pre>
6520
6521<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6522<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6523 a signed addition of the two arguments, and indicate whether an overflow
6524 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6525
6526<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527<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]6528 be of integer types of any bit width, but they must have the same bit
6529 width. The second element of the result structure must be of
6530 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6531 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532
6533<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6534<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6535 a signed addition of the two variables. They return a structure &mdash; the
6536 first element of which is the signed summation, and the second element of
6537 which is a bit specifying if the signed summation resulted in an
6538 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6539
6540<h5>Examples:</h5>
6541<pre>
6542 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6543 %sum = extractvalue {i32, i1} %res, 0
6544 %obit = extractvalue {i32, i1} %res, 1
6545 br i1 %obit, label %overflow, label %normal
6546</pre>
6547
6548</div>
6549
6550<!-- _______________________________________________________________________ -->
6551<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6552 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553</div>
6554
6555<div class="doc_text">
6556
6557<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6558<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]6559 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6560
6561<pre>
6562 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6563 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6564 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6565</pre>
6566
6567<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6568<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569 an unsigned addition of the two arguments, and indicate whether a carry
6570 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6571
6572<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573<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]6574 be of integer types of any bit width, but they must have the same bit
6575 width. The second element of the result structure must be of
6576 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6577 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6578
6579<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6580<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6581 an unsigned addition of the two arguments. They return a structure &mdash;
6582 the first element of which is the sum, and the second element of which is a
6583 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6584
6585<h5>Examples:</h5>
6586<pre>
6587 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6588 %sum = extractvalue {i32, i1} %res, 0
6589 %obit = extractvalue {i32, i1} %res, 1
6590 br i1 %obit, label %carry, label %normal
6591</pre>
6592
6593</div>
6594
6595<!-- _______________________________________________________________________ -->
6596<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6597 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6598</div>
6599
6600<div class="doc_text">
6601
6602<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6603<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]6604 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6605
6606<pre>
6607 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6608 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6609 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6610</pre>
6611
6612<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6613<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6614 a signed subtraction of the two arguments, and indicate whether an overflow
6615 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6616
6617<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618<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]6619 be of integer types of any bit width, but they must have the same bit
6620 width. The second element of the result structure must be of
6621 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6622 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623
6624<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6625<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6626 a signed subtraction of the two arguments. They return a structure &mdash;
6627 the first element of which is the subtraction, and the second element of
6628 which is a bit specifying if the signed subtraction resulted in an
6629 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6630
6631<h5>Examples:</h5>
6632<pre>
6633 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6634 %sum = extractvalue {i32, i1} %res, 0
6635 %obit = extractvalue {i32, i1} %res, 1
6636 br i1 %obit, label %overflow, label %normal
6637</pre>
6638
6639</div>
6640
6641<!-- _______________________________________________________________________ -->
6642<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6643 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6644</div>
6645
6646<div class="doc_text">
6647
6648<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6649<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]6650 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6651
6652<pre>
6653 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6654 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6655 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6656</pre>
6657
6658<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6660 an unsigned subtraction of the two arguments, and indicate whether an
6661 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6662
6663<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664<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]6665 be of integer types of any bit width, but they must have the same bit
6666 width. The second element of the result structure must be of
6667 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6668 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669
6670<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6672 an unsigned subtraction of the two arguments. They return a structure &mdash;
6673 the first element of which is the subtraction, and the second element of
6674 which is a bit specifying if the unsigned subtraction resulted in an
6675 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6676
6677<h5>Examples:</h5>
6678<pre>
6679 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6680 %sum = extractvalue {i32, i1} %res, 0
6681 %obit = extractvalue {i32, i1} %res, 1
6682 br i1 %obit, label %overflow, label %normal
6683</pre>
6684
6685</div>
6686
6687<!-- _______________________________________________________________________ -->
6688<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6689 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690</div>
6691
6692<div class="doc_text">
6693
6694<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6695<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]6696 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6697
6698<pre>
6699 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6700 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6701 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6702</pre>
6703
6704<h5>Overview:</h5>
6705
6706<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6707 a signed multiplication of the two arguments, and indicate whether an
6708 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6709
6710<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6711<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]6712 be of integer types of any bit width, but they must have the same bit
6713 width. The second element of the result structure must be of
6714 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6715 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6716
6717<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6718<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6719 a signed multiplication of the two arguments. They return a structure &mdash;
6720 the first element of which is the multiplication, and the second element of
6721 which is a bit specifying if the signed multiplication resulted in an
6722 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6723
6724<h5>Examples:</h5>
6725<pre>
6726 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6727 %sum = extractvalue {i32, i1} %res, 0
6728 %obit = extractvalue {i32, i1} %res, 1
6729 br i1 %obit, label %overflow, label %normal
6730</pre>
6731
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6732</div>
6733
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6734<!-- _______________________________________________________________________ -->
6735<div class="doc_subsubsection">
6736 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6737</div>
6738
6739<div class="doc_text">
6740
6741<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6742<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]6743 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6744
6745<pre>
6746 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6747 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6748 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6749</pre>
6750
6751<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6752<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6753 a unsigned multiplication of the two arguments, and indicate whether an
6754 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6755
6756<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6757<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]6758 be of integer types of any bit width, but they must have the same bit
6759 width. The second element of the result structure must be of
6760 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6761 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6762
6763<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6764<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6765 an unsigned multiplication of the two arguments. They return a structure
6766 &mdash; the first element of which is the multiplication, and the second
6767 element of which is a bit specifying if the unsigned multiplication resulted
6768 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6769
6770<h5>Examples:</h5>
6771<pre>
6772 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6773 %sum = extractvalue {i32, i1} %res, 0
6774 %obit = extractvalue {i32, i1} %res, 1
6775 br i1 %obit, label %overflow, label %normal
6776</pre>
6777
6778</div>
6779
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6780<!-- ======================================================================= -->
6781<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6782 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6783</div>
6784
6785<div class="doc_text">
6786
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6787<p>Half precision floating point is a storage-only format. This means that it is
6788 a dense encoding (in memory) but does not support computation in the
6789 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6790
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6791<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6792 value as an i16, then convert it to float with <a
6793 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6794 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6795 double etc). To store the value back to memory, it is first converted to
6796 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6797 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6798 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6799</div>
6800
6801<!-- _______________________________________________________________________ -->
6802<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6803 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6804</div>
6805
6806<div class="doc_text">
6807
6808<h5>Syntax:</h5>
6809<pre>
6810 declare i16 @llvm.convert.to.fp16(f32 %a)
6811</pre>
6812
6813<h5>Overview:</h5>
6814<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6815 a conversion from single precision floating point format to half precision
6816 floating point format.</p>
6817
6818<h5>Arguments:</h5>
6819<p>The intrinsic function contains single argument - the value to be
6820 converted.</p>
6821
6822<h5>Semantics:</h5>
6823<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6824 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6825 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6826 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6827
6828<h5>Examples:</h5>
6829<pre>
6830 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6831 store i16 %res, i16* @x, align 2
6832</pre>
6833
6834</div>
6835
6836<!-- _______________________________________________________________________ -->
6837<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6838 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6839</div>
6840
6841<div class="doc_text">
6842
6843<h5>Syntax:</h5>
6844<pre>
6845 declare f32 @llvm.convert.from.fp16(i16 %a)
6846</pre>
6847
6848<h5>Overview:</h5>
6849<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6850 a conversion from half precision floating point format to single precision
6851 floating point format.</p>
6852
6853<h5>Arguments:</h5>
6854<p>The intrinsic function contains single argument - the value to be
6855 converted.</p>
6856
6857<h5>Semantics:</h5>
6858<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6859 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6860 precision floating point format. The input half-float value is represented by
6861 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6862
6863<h5>Examples:</h5>
6864<pre>
6865 %a = load i16* @x, align 2
6866 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6867</pre>
6868
6869</div>
6870
6871<!-- ======================================================================= -->
6872<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6873 <a name="int_debugger">Debugger Intrinsics</a>
6874</div>
6875
6876<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6877
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6878<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6879 prefix), are described in
6880 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6881 Level Debugging</a> document.</p>
6882
6883</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6884
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6885<!-- ======================================================================= -->
6886<div class="doc_subsection">
6887 <a name="int_eh">Exception Handling Intrinsics</a>
6888</div>
6889
6890<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6891
6892<p>The LLVM exception handling intrinsics (which all start with
6893 <tt>llvm.eh.</tt> prefix), are described in
6894 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6895 Handling</a> document.</p>
6896
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6897</div>
6898
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6899<!-- ======================================================================= -->
6900<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6901 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6902</div>
6903
6904<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905
6906<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6907 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6908 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909 function pointer lacking the nest parameter - the caller does not need to
6910 provide a value for it. Instead, the value to use is stored in advance in a
6911 "trampoline", a block of memory usually allocated on the stack, which also
6912 contains code to splice the nest value into the argument list. This is used
6913 to implement the GCC nested function address extension.</p>
6914
6915<p>For example, if the function is
6916 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6917 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6918 follows:</p>
6919
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6920<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6921 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6922 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6923 %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]6924 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6925</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6926
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6927<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6928 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6930</div>
6931
6932<!-- _______________________________________________________________________ -->
6933<div class="doc_subsubsection">
6934 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6935</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6936
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6937<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6939<h5>Syntax:</h5>
6940<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941 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]6942</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6944<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6946 function pointer suitable for executing it.</p>
6947
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6948<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6949<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6950 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6951 sufficiently aligned block of memory; this memory is written to by the
6952 intrinsic. Note that the size and the alignment are target-specific - LLVM
6953 currently provides no portable way of determining them, so a front-end that
6954 generates this intrinsic needs to have some target-specific knowledge.
6955 The <tt>func</tt> argument must hold a function bitcast to
6956 an <tt>i8*</tt>.</p>
6957
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6958<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6959<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6960 dependent code, turning it into a function. A pointer to this function is
6961 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6962 function pointer type</a> before being called. The new function's signature
6963 is the same as that of <tt>func</tt> with any arguments marked with
6964 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6965 is allowed, and it must be of pointer type. Calling the new function is
6966 equivalent to calling <tt>func</tt> with the same argument list, but
6967 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6968 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6969 by <tt>tramp</tt> is modified, then the effect of any later call to the
6970 returned function pointer is undefined.</p>
6971
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6972</div>
6973
6974<!-- ======================================================================= -->
6975<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6976 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6977</div>
6978
6979<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6981<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6982 hardware constructs for atomic operations and memory synchronization. This
6983 provides an interface to the hardware, not an interface to the programmer. It
6984 is aimed at a low enough level to allow any programming models or APIs
6985 (Application Programming Interfaces) which need atomic behaviors to map
6986 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6987 hardware provides a "universal IR" for source languages, it also provides a
6988 starting point for developing a "universal" atomic operation and
6989 synchronization IR.</p>
6990
6991<p>These do <em>not</em> form an API such as high-level threading libraries,
6992 software transaction memory systems, atomic primitives, and intrinsic
6993 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6994 application libraries. The hardware interface provided by LLVM should allow
6995 a clean implementation of all of these APIs and parallel programming models.
6996 No one model or paradigm should be selected above others unless the hardware
6997 itself ubiquitously does so.</p>
6998
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6999</div>
7000
7001<!-- _______________________________________________________________________ -->
7002<div class="doc_subsubsection">
7003 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7004</div>
7005<div class="doc_text">
7006<h5>Syntax:</h5>
7007<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7008 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]7009</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7010
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7011<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7012<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7013 specific pairs of memory access types.</p>
7014
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7015<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7016<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7017 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7018 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7019 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7021<ul>
7022 <li><tt>ll</tt>: load-load barrier</li>
7023 <li><tt>ls</tt>: load-store barrier</li>
7024 <li><tt>sl</tt>: store-load barrier</li>
7025 <li><tt>ss</tt>: store-store barrier</li>
7026 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7027</ul>
7028
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7030<p>This intrinsic causes the system to enforce some ordering constraints upon
7031 the loads and stores of the program. This barrier does not
7032 indicate <em>when</em> any events will occur, it only enforces
7033 an <em>order</em> in which they occur. For any of the specified pairs of load
7034 and store operations (f.ex. load-load, or store-load), all of the first
7035 operations preceding the barrier will complete before any of the second
7036 operations succeeding the barrier begin. Specifically the semantics for each
7037 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7038
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7039<ul>
7040 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7041 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7042 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7044 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7045 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7046 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7047 load after the barrier begins.</li>
7048</ul>
7049
7050<p>These semantics are applied with a logical "and" behavior when more than one
7051 is enabled in a single memory barrier intrinsic.</p>
7052
7053<p>Backends may implement stronger barriers than those requested when they do
7054 not support as fine grained a barrier as requested. Some architectures do
7055 not need all types of barriers and on such architectures, these become
7056 noops.</p>
7057
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7058<h5>Example:</h5>
7059<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7060%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7061%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7062 store i32 4, %ptr
7063
7064%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7065 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7066 <i>; guarantee the above finishes</i>
7067 store i32 8, %ptr <i>; before this begins</i>
7068</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7070</div>
7071
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7072<!-- _______________________________________________________________________ -->
7073<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7074 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7075</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7077<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7078
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7079<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7081 any integer bit width and for different address spaces. Not all targets
7082 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7083
7084<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7085 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7086 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7087 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7088 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]7089</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7091<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7092<p>This loads a value in memory and compares it to a given value. If they are
7093 equal, it stores a new value into the memory.</p>
7094
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7096<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7097 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7098 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7099 this integer type. While any bit width integer may be used, targets may only
7100 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7101
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7102<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7103<p>This entire intrinsic must be executed atomically. It first loads the value
7104 in memory pointed to by <tt>ptr</tt> and compares it with the
7105 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7106 memory. The loaded value is yielded in all cases. This provides the
7107 equivalent of an atomic compare-and-swap operation within the SSA
7108 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7110<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7111<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7112%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7113%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7114 store i32 4, %ptr
7115
7116%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7117%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7118 <i>; yields {i32}:result1 = 4</i>
7119%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7120%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7121
7122%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7123%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7124 <i>; yields {i32}:result2 = 8</i>
7125%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7126
7127%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7128</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7129
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7130</div>
7131
7132<!-- _______________________________________________________________________ -->
7133<div class="doc_subsubsection">
7134 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7135</div>
7136<div class="doc_text">
7137<h5>Syntax:</h5>
7138
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7139<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7140 integer bit width. Not all targets support all bit widths however.</p>
7141
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7142<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7143 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7144 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7145 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7146 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]7147</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7148
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7150<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7151 the value from memory. It then stores the value in <tt>val</tt> in the memory
7152 at <tt>ptr</tt>.</p>
7153
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7154<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7155<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7156 the <tt>val</tt> argument and the result must be integers of the same bit
7157 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7158 integer type. The targets may only lower integer representations they
7159 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7160
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7161<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7163 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7164 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Examples:</h5>
7167<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7168%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7169%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170 store i32 4, %ptr
7171
7172%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7173%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7174 <i>; yields {i32}:result1 = 4</i>
7175%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7176%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7177
7178%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7179%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180 <i>; yields {i32}:result2 = 8</i>
7181
7182%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7183%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7184</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7185
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186</div>
7187
7188<!-- _______________________________________________________________________ -->
7189<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7190 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191
7192</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7194<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7195
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7196<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7197<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7198 any integer bit width. Not all targets support all bit widths however.</p>
7199
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7200<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7201 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7202 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7203 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7204 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]7205</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7207<h5>Overview:</h5>
7208<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7209 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7210
7211<h5>Arguments:</h5>
7212<p>The intrinsic takes two arguments, the first a pointer to an integer value
7213 and the second an integer value. The result is also an integer value. These
7214 integer types can have any bit width, but they must all have the same bit
7215 width. The targets may only lower integer representations they support.</p>
7216
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7217<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218<p>This intrinsic does a series of operations atomically. It first loads the
7219 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7220 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]7221
7222<h5>Examples:</h5>
7223<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7224%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7225%ptr = bitcast i8* %mallocP to i32*
7226 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7227%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7228 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7229%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7230 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7231%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7232 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7233%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7234</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7235
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7236</div>
7237
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7238<!-- _______________________________________________________________________ -->
7239<div class="doc_subsubsection">
7240 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7241
7242</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7244<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7245
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7246<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7247<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7248 any integer bit width and for different address spaces. Not all targets
7249 support all bit widths however.</p>
7250
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7251<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7252 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7253 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7254 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7255 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]7256</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7257
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7259<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7260 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7261
7262<h5>Arguments:</h5>
7263<p>The intrinsic takes two arguments, the first a pointer to an integer value
7264 and the second an integer value. The result is also an integer value. These
7265 integer types can have any bit width, but they must all have the same bit
7266 width. The targets may only lower integer representations they support.</p>
7267
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7268<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7269<p>This intrinsic does a series of operations atomically. It first loads the
7270 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7271 result to <tt>ptr</tt>. It yields the original value stored
7272 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7273
7274<h5>Examples:</h5>
7275<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7276%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7277%ptr = bitcast i8* %mallocP to i32*
7278 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7279%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7280 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7281%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7282 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7283%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7284 <i>; yields {i32}:result3 = 2</i>
7285%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7286</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7287
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7288</div>
7289
7290<!-- _______________________________________________________________________ -->
7291<div class="doc_subsubsection">
7292 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7293 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7294 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7295 <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]7296</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7297
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7298<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7300<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7301<p>These are overloaded intrinsics. You can
7302 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7303 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7304 bit width and for different address spaces. Not all targets support all bit
7305 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7306
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7308 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7309 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7310 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7311 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]7312</pre>
7313
7314<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7315 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7316 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7317 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7318 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]7319</pre>
7320
7321<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7322 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7323 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7324 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7325 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]7326</pre>
7327
7328<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7329 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7330 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7331 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7332 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]7333</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7334
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7335<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7336<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7337 the value stored in memory at <tt>ptr</tt>. It yields the original value
7338 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7340<h5>Arguments:</h5>
7341<p>These intrinsics take two arguments, the first a pointer to an integer value
7342 and the second an integer value. The result is also an integer value. These
7343 integer types can have any bit width, but they must all have the same bit
7344 width. The targets may only lower integer representations they support.</p>
7345
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7346<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7347<p>These intrinsics does a series of operations atomically. They first load the
7348 value stored at <tt>ptr</tt>. They then do the bitwise
7349 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7350 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7351
7352<h5>Examples:</h5>
7353<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7354%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7355%ptr = bitcast i8* %mallocP to i32*
7356 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7357%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7358 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7359%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7360 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7361%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7362 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7363%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7364 <i>; yields {i32}:result3 = FF</i>
7365%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7366</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7368</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7369
7370<!-- _______________________________________________________________________ -->
7371<div class="doc_subsubsection">
7372 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7373 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7374 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7375 <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]7376</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7377
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7378<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7379
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7380<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7381<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7382 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7383 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7384 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7385
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7386<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7387 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7388 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7389 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7390 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]7391</pre>
7392
7393<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7394 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7395 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7396 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7397 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]7398</pre>
7399
7400<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7401 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7402 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7403 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7404 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]7405</pre>
7406
7407<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7408 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7409 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7410 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7411 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]7412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7413
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7414<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7415<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7416 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7417 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7418
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7419<h5>Arguments:</h5>
7420<p>These intrinsics take two arguments, the first a pointer to an integer value
7421 and the second an integer value. The result is also an integer value. These
7422 integer types can have any bit width, but they must all have the same bit
7423 width. The targets may only lower integer representations they support.</p>
7424
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7425<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7426<p>These intrinsics does a series of operations atomically. They first load the
7427 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7428 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7429 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7430
7431<h5>Examples:</h5>
7432<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7433%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7434%ptr = bitcast i8* %mallocP to i32*
7435 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7436%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7437 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7438%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7439 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7440%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7441 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7442%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7443 <i>; yields {i32}:result3 = 8</i>
7444%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7445</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7446
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7447</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7448
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7449
7450<!-- ======================================================================= -->
7451<div class="doc_subsection">
7452 <a name="int_memorymarkers">Memory Use Markers</a>
7453</div>
7454
7455<div class="doc_text">
7456
7457<p>This class of intrinsics exists to information about the lifetime of memory
7458 objects and ranges where variables are immutable.</p>
7459
7460</div>
7461
7462<!-- _______________________________________________________________________ -->
7463<div class="doc_subsubsection">
7464 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7465</div>
7466
7467<div class="doc_text">
7468
7469<h5>Syntax:</h5>
7470<pre>
7471 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7472</pre>
7473
7474<h5>Overview:</h5>
7475<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7476 object's lifetime.</p>
7477
7478<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7479<p>The first argument is a constant integer representing the size of the
7480 object, or -1 if it is variable sized. The second argument is a pointer to
7481 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7482
7483<h5>Semantics:</h5>
7484<p>This intrinsic indicates that before this point in the code, the value of the
7485 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]7486 never be used and has an undefined value. A load from the pointer that
7487 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7488 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7489
7490</div>
7491
7492<!-- _______________________________________________________________________ -->
7493<div class="doc_subsubsection">
7494 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7495</div>
7496
7497<div class="doc_text">
7498
7499<h5>Syntax:</h5>
7500<pre>
7501 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7502</pre>
7503
7504<h5>Overview:</h5>
7505<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7506 object's lifetime.</p>
7507
7508<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7509<p>The first argument is a constant integer representing the size of the
7510 object, or -1 if it is variable sized. The second argument is a pointer to
7511 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7512
7513<h5>Semantics:</h5>
7514<p>This intrinsic indicates that after this point in the code, the value of the
7515 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7516 never be used and has an undefined value. Any stores into the memory object
7517 following this intrinsic may be removed as dead.
7518
7519</div>
7520
7521<!-- _______________________________________________________________________ -->
7522<div class="doc_subsubsection">
7523 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7524</div>
7525
7526<div class="doc_text">
7527
7528<h5>Syntax:</h5>
7529<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7530 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7531</pre>
7532
7533<h5>Overview:</h5>
7534<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7535 a memory object will not change.</p>
7536
7537<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7538<p>The first argument is a constant integer representing the size of the
7539 object, or -1 if it is variable sized. The second argument is a pointer to
7540 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7541
7542<h5>Semantics:</h5>
7543<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7544 the return value, the referenced memory location is constant and
7545 unchanging.</p>
7546
7547</div>
7548
7549<!-- _______________________________________________________________________ -->
7550<div class="doc_subsubsection">
7551 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7552</div>
7553
7554<div class="doc_text">
7555
7556<h5>Syntax:</h5>
7557<pre>
7558 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7559</pre>
7560
7561<h5>Overview:</h5>
7562<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7563 a memory object are mutable.</p>
7564
7565<h5>Arguments:</h5>
7566<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7567 The second argument is a constant integer representing the size of the
7568 object, or -1 if it is variable sized and the third argument is a pointer
7569 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7570
7571<h5>Semantics:</h5>
7572<p>This intrinsic indicates that the memory is mutable again.</p>
7573
7574</div>
7575
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7576<!-- ======================================================================= -->
7577<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7578 <a name="int_general">General Intrinsics</a>
7579</div>
7580
7581<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7582
7583<p>This class of intrinsics is designed to be generic and has no specific
7584 purpose.</p>
7585
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7586</div>
7587
7588<!-- _______________________________________________________________________ -->
7589<div class="doc_subsubsection">
7590 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7591</div>
7592
7593<div class="doc_text">
7594
7595<h5>Syntax:</h5>
7596<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7597 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]7598</pre>
7599
7600<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7601<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7602
7603<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7604<p>The first argument is a pointer to a value, the second is a pointer to a
7605 global string, the third is a pointer to a global string which is the source
7606 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7607
7608<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7609<p>This intrinsic allows annotation of local variables with arbitrary strings.
7610 This can be useful for special purpose optimizations that want to look for
7611 these annotations. These have no other defined use, they are ignored by code
7612 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7613
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7614</div>
7615
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7616<!-- _______________________________________________________________________ -->
7617<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7618 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7619</div>
7620
7621<div class="doc_text">
7622
7623<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7624<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7625 any integer bit width.</p>
7626
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7627<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7628 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7629 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7630 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7631 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7632 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]7633</pre>
7634
7635<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7636<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7637
7638<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639<p>The first argument is an integer value (result of some expression), the
7640 second is a pointer to a global string, the third is a pointer to a global
7641 string which is the source file name, and the last argument is the line
7642 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7643
7644<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7645<p>This intrinsic allows annotations to be put on arbitrary expressions with
7646 arbitrary strings. This can be useful for special purpose optimizations that
7647 want to look for these annotations. These have no other defined use, they
7648 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7649
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7650</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7651
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7652<!-- _______________________________________________________________________ -->
7653<div class="doc_subsubsection">
7654 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7655</div>
7656
7657<div class="doc_text">
7658
7659<h5>Syntax:</h5>
7660<pre>
7661 declare void @llvm.trap()
7662</pre>
7663
7664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7666
7667<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7668<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7669
7670<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7671<p>This intrinsics is lowered to the target dependent trap instruction. If the
7672 target does not have a trap instruction, this intrinsic will be lowered to
7673 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7674
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7675</div>
7676
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7677<!-- _______________________________________________________________________ -->
7678<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7679 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7680</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7681
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7682<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7684<h5>Syntax:</h5>
7685<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7686 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7687</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7689<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7690<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7691 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7692 ensure that it is placed on the stack before local variables.</p>
7693
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7694<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7695<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7696 arguments. The first argument is the value loaded from the stack
7697 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7698 that has enough space to hold the value of the guard.</p>
7699
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7700<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7701<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7702 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7703 stack. This is to ensure that if a local variable on the stack is
7704 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7705 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7707 function.</p>
7708
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7709</div>
7710
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7711<!-- _______________________________________________________________________ -->
7712<div class="doc_subsubsection">
7713 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7714</div>
7715
7716<div class="doc_text">
7717
7718<h5>Syntax:</h5>
7719<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7720 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7721 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7722</pre>
7723
7724<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7725<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7726 the optimizers to determine at compile time whether a) an operation (like
7727 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7728 runtime check for overflow isn't necessary. An object in this context means
7729 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7730
7731<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7732<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7733 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7734 is a boolean 0 or 1. This argument determines whether you want the
7735 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]7736 1, variables are not allowed.</p>
7737
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7738<h5>Semantics:</h5>
7739<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7740 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7741 depending on the <tt>type</tt> argument, if the size cannot be determined at
7742 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7743
7744</div>
7745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7746<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7747<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7748<address>
7749 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7750 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7751 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7753
7754 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7755 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7756 Last modified: $Date$
7757</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7758
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7759</body>
7760</html>